W. Va. Code R. § 64-23-7 - Requirements for Radiation Usage in the Healing Arts

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Current through Register Vol. XXXVIII, No. 51, December 23, 2021

7.1. Scope - This Section establishes requirements for which a registrant is responsible, for use of x-ray equipment by or under the supervision of an individual authorized by and registered in accordance with West Virginia statutes to engage in the healing arts or veterinary medicine. The provisions of this Section are in addition to, and not in substitution for, other applicable provisions of this rule.

7.2. Definitions - As used in this Section, the following definitions apply:

7.2.1. Accessible Surface - the external surface of the enclosure or housing of the radiation producing machine as provided by the manufacturer.

7.2.2. Added Filtration - any filtration which is in addition to the inherent filtration.

7.2.3. Aluminum Equivalent - the thickness of aluminum (type one thousand one hundred [1100] alloy) affording the same attenuation, under specified conditions, as the material in question. (The nominal chemical composition of type one thousand one hundred [1100] aluminum alloy is ninety-nine [99.00] percent minimum aluminum, twelve one-hundredths [0.12] percent copper.)

7.2.4. Assembler - any person engaged in the business of assembling, replacing, or installing one or more components into an x-ray system or subsystem. The term includes the owner of an x-ray system or his or her employee or agent who assembles components into an x-ray system that is subsequently used to provide professional or commercial services.

7.2.5. Attenuation Block - a block or stack, having dimensions twenty (20) centimeters by twenty (20) centimeters by three and eight-tenths (3.8) centimeters, of type 1100 aluminum alloy or other materials having equivalent attenuation.

7.2.6. Automatic Exposure Control (AEC) - a device which automatically controls one or more technique factors in order to obtain at a preselected locations a required quantity of radiation (Includes devices such as phototimers and ion chambers).

7.2.7. Barrier - the material, excluding filters, placed in the useful and scattered beam, for protection purposes, to reduce the radiation exposure.

7.2.8. Beam Axis - a line from the source through the centers of the x-ray fields.

7.2.9. Beam-limiting device - a device which provides a means to restrict the dimensions of the x-ray field.

7.2.10. C-arm X-ray System - an x-ray system in which the image receptor and x-ray tube housing assembly are connected by a common mechanical support system in order to maintain a desired spatial relationship. This system is designed to allow a change in the projection of the beam through the patient without a change in the position of the patient.

7.2.11. Cephalometric Device - a device intended for the radiographic visualization and measurement of the dimensions of the human head.

7.2.12. Certified Components - components of x-ray systems which are subject to regulations promulgated under Public Law 90-602, the Radiation Control for Health and Safety Act of 1968, the Food and Drug Administration.

7.2.13. Certified System - any x-ray system which has one or more certified components.

7.2.14. Changeable Filters - any filter, exclusive of inherent filtration, which can be removed from the useful beam through any electronic, mechanical, or physical process.

7.2.15. Coefficient of Variation - the ratio of the standard deviation to the mean value of a set of observations. It is estimated using the following equation:

where:

{FUNC s} = Standard deviation of the observed values;

{OVERLINE FUNC ALIGNC x} = Mean value of observations in sample;

{FUNC x SUB i} = i_th observation in sample;

{FUNC n} = Number of observations in sample.

7.2.16. Collimator - a device or mechanism by which the x-ray beam is restricted in size.

7.2.17. Computed Tomography (CT) - the production of a tomogram by the acquisition and computer processing of x-ray transmission data.

7.2.18. Control Panel - that part of the x-ray control upon which are mounted the switches, knobs, pushbuttons, and other hardware necessary for manually setting the technique factors.

7.2.19. Cooling Curve - the graphical relationship between heat units stored and cooling time.

7.2.20. Dead-man Switch - a switch so constructed that circuit-closing contact can be maintained only be continuous pressure on the switch by the operator.

7.2.21. Detector - a device which in the presence of radiation provides a signal or other indication suitable for use in measuring one or more quantities of incident radiation.

7.2.22. Diagnostic-type Protective Tube Housing - an x-ray tube housing so constructed that the leakage radiation at a distance of one (1) meter from the target cannot exceed one hundred (100) milliroentgens in one (1) hour when the tube is operated at its maximum continuous rated current for the maximum rated tube potential.

7.2.23. Diagnostic Source Assembly - the tube housing assembly with a beam-limiting device attached.

7.2.24. Diagnostic X-ray System - an x-ray system designed for irradiation of any part of the human or animal body for the purpose of diagnosis or visualization.

7.2.25. Diagnostic X-ray Imaging System - an assemblage of components for the generation, emission and reception of x-rays and the transformation, storage and visual display of the resultant x-ray image.

7.2.26. Diaphragm - a device or mechanism by which the x-ray beam is restricted in size.

7.2.27. Direct Scattered Radiation - that scattered radiation which has been deviated in direction only by materials irradiated by the useful beam (See "Scattered Radiation").

7.2.28. Entrance Exposure Rate - the exposure free in air per unit time at the point where the center of the useful beam enters the patient.

7.2.29. Field Emission Equipment - equipment which uses an x-ray tube in which electron emission from the cathode is due solely to the action of an electric field.

7.2.30. Filter - the material placed in the useful beam to absorb preferentially selected radiations.

7.2.31. Fluoroscopic Imaging Assembly - a subsystem in which x-ray photons produce a visible image. It includes the image receptor or receptors such as the image intensifier and spot-film device, electrical interlocks, if any, and structural material providing linkage between the image receptor and diagnostic source assembly.

7.2.32. Focal Spot (Actual) - the area projected on the anode on the x-ray tube bombarded by electrons accelerated from the cathode and from which the useful beam originates.

7.2.33. General Purpose Radiographic X-ray System - any radiographic x-ray system which, by design, is not limited to radiographic examination of specific anatomical regions.

7.2.34. Gonadal Shield - a protective barrier for the testes or ovaries.

7.2.35. Half-value Layer (HVL) - the thickness of specified material which attenuates the beam of radiation to an extent such that the exposure rate is reduced to one-half of its original value. In this definition, the contribution of all scattered radiation, other than any which might be present initially in the beam concerned, is deemed to be excluded.

7.2.36. Healing Arts Screening - the testing of human beings using x-ray machines for the detection or evaluation of health indications when such tests are not specifically and individually ordered by a licensed practitioner of the healing arts legally authorized to prescribe such x-ray tests for the purpose of diagnosis or treatment.

7.2.37. Heat Unit - a unit of energy equal to the product of the peak kilovoltage, milliamperes, and seconds, i.e., kVp x mA x second.

7.2.38. Image Intensifier - a device, installed in its housing, which instantaneously converts an x-ray pattern into a corresponding light image of higher intensity.

7.2.39. Image Receptor - any device, such as a fluorescent screen or radiographic film, which transforms incident x-ray photons either into a visible image or into another form which can be made into a visible image by further transformations.

7.2.40. Image Receptor Support - for mammographic systems, that part of the system designed to support the image receptor during mammography.

7.2.41. Inherent Filtration - the filtration of the useful beam provided by the permanently installed components of the tube housing assembly.

7.2.42. Interlock - a device for precluding access to an area of radiation hazard either by preventing entry or by automatically removing the hazard.

7.2.43. Irradiation - the exposure of matter to ionizing radiation.

7.2.44. kV - kilovolts.

7.2.45. kVp - the maximum value of the potential difference across the x-ray tube during an exposure.

7.2.46. kWs - kilowatt second.

7.2.47. Lead Equivalent - the thickness of lead affording the same attenuation, under specified conditions, as the material in question.

7.2.48. Leakage Technique Factors - the technique factors associated with the diagnostic source assembly which are used in measuring leakage radiation. They are defined as follows:

7.2.48.a. For diagnostic source assemblies intended for capacitor energy storage equipment, the maximum-rated peak tube potential and the maximum-rated number of exposures in an hour for operation at the maximum-rated peak tube potential with the quantity of charge per exposure being ten (10) millicoulombs, i.e., ten (10) milliampere seconds, or the minimum obtainable from the unit, whichever is larger;

7.2.48.b. For diagnostic source assemblies intended for field emission equipment rated for pulsed operation, the maximum-rated peak tube potential and the maximum-rated number of x-ray pulses in an hour for operation at the maximum-rated peak tube potential;

7.2.48.c. For all other diagnostic source assemblies, the maximum-rated peak tube potential and the maximum-rated continuous tube current for the maximum-rated peak tube potential.

7.2.49. Light Field - that area of the intersection of the light beam from the beam-limiting device and one (1) of the set of planes parallel to and including the plane of the image receptor, whose perimeter is the locus of points at which the illumination is one-fourth (¹/₄) of the maximum in the intersection.

7.2.50. Line-voltage Regulation - the difference between the no-load and the load line potentials expressed as a percent of the load line potential. It is calculated using the following equation:

Percent line-voltage regulation = 100 (V_n-V_l)/V_l

where:

V_n = No-load line potential; and

V_l = Load line potential.

7.2.51. mA - milliampere.

7.2.52. mAs - milliampere second.

7.2.53. Maximum Line Current - the root-mean-square current in the supply line of an x-ray machine operating at its maximum rating.

7.2.54. Mobile X-ray Equipment - x-ray equipment mounted on a permanent base with wheels or casters for moving while completely assembled.

7.2.55. Patient - an individual or animal subjected to healing arts examination, diagnosis, or treatment.

7.2.56. PBL - See Positive Beam Limitation.

7.2.57. Peak Tube Potential - the maximum value of the potential difference across the x-ray tube during an exposure.

7.2.58. Phantom - a volume of material behaving in a manner similar to tissue with respect to the attenuation and scattering of radiation. This requires that both the atomic number (Z) and the density of the material be similar to that of tissue.

7.2.59. PID - a device on dental x-ray equipment used to indicate the beam position and to establish a definite source-surface (skin) distance. It may or may not incorporate or serve as a beam-limiting device.

7.2.60. Portable X-ray Equipment - x-ray equipment designed to be hand-carried.

7.2.61. Position Indicating Device - a device on dental x-ray equipment used to indicate the beam position and to establish a definite source-surface (skin) distance. It may or may not incorporate or serve as a beam-limiting device.

7.2.62. Positive Beam Limitation - the automatic or semi-automatic adjustment of an x-ray beam to the size of the selected image receptor, whereby exposures cannot be made without such adjustment.

7.2.63. Primary Protective Barrier - the material, excluding filters, placed in the useful beam, for protection purposes, to reduce the radiation exposure.

7.2.64. Protective Apron - an apron made of radiation absorbing materials used to reduce radiation exposure.

7.2.65. Protective Glove - a glove made of radiation absorbing materials used to reduce radiation exposure.

7.2.66. Qualified Expert - an individual who has demonstrated to the satisfaction of the agency that he possesses the knowledge and training to measure ionizing radiation, to evaluate safety techniques, and to advise regarding radiation protective needs.

7.2.67. Radiation Detector - a device which in the presence of radiation provides a signal or other indication suitable for use in measuring one or more quantities of incident radiation.

7.2.68. Radiation Therapy Simulation System - a radiographic or fluoroscopic x-ray system intended for localizing the volume to be exposed during radiation therapy and confirming the position and size of the therapeutic irradiation field.

7.2.69. Radiograph - an image receptor on which the image is created directly or indirectly by an x-ray pattern and results in a permanent record.

7.2.70. Radiographic Imaging System - any system whereby a permanent or semi-permanent image is recorded on an image receptor by the action of ionizing radiation.

7.2.71. Rating - the operating limits as specified by the component manufacturer.

7.2.72. Recording - producing a permanent form of an image resulting from x-ray photons.

7.2.73. Registrant as used in this Section - any person who owns or possesses and administratively controls and x-ray system which is used to deliberately expose humans or animals to the useful beam of the system and is required by the provisions of Sections 4. and 5. of this rule to register with this agency.

7.2.74. Scattered Radiation - radiation that, during passage through matter, has been deviated in direction.

7.2.75. Secondary Protective Barrier - a barrier sufficient to attenuate the stray radiation to the required degree.

7.2.76. Shutter - a device attached to the tube housing assembly which can intercept the entire cross Sectional area of the useful beam and which has a lead equivalency not less than that of the tube housing assembly.

7.2.77. Source-image Distance (SID) - the distance from the source to the center of the input surface of the image receptor.

7.2.78. Source - the focal spot of the x-ray tube.

7.2.79. Spot Film - a radiograph which is made during a fluoroscopic examination to permanently record conditions which exist during that fluoroscopic procedure.

7.2.80. Spot-film Device - a device intended to transport or position a radiographic image receptor between the x-ray source and fluoroscopic image receptor. It includes a device intended to hold a cassette over the input end of an image intensifier for the purpose of making a radiograph.

7.2.81. SSD - the distance between the source and the skin entrance plane of the patient.

7.2.82. Stationary X-ray Equipment - x-ray equipment which is installed in a fixed location.

7.2.83. Stray Radiation - the sum of leakage and scattered radiation.

7.2.84. Technique Factors - the following conditions of operation:

7.2.84.a. For capacitor energy storage equipment, peak tube potential in kV and quantity of charge in mAs;

7.2.84.b. For field emission equipment rated for pulsed operation, peak tube potential in kV, and number of x-ray pulses;

7.2.84.c. For CT x-ray systems designed for pulsed operation, peak tube potential in kV, scan time in seconds, and either tube current in mA, x-ray pulse width in seconds, and the number of x-ray pulses per scan, or the product of tube current, x-ray pulse width, and the number of x-ray pulses in mAs;

7.2.84.d. For CT x-ray systems not designed for pulsed operation, peak tube potential in kV, and either tube current in mA and scan time in seconds, or the product of tube current and exposure time in mAs and the scan time when the scan time and exposure time are equivalent; and

7.2.84.e. For all other equipment, peak tube potential in kV, and either tube current in mA and exposure time in seconds, or the product of tube current and exposure time in mAs.

7.2.85. Termination of Irradiation - the stopping of irradiation in a fashion which will not permit continuance of irradiation without the resetting of operating conditions at the control panel.

7.2.86. Therapeutic-type Tube Housing:

7.2.86.a. For x-ray therapy equipment not capable of operating at five hundred (500) kVp or above, the following definition applies: An x-ray tube housing so constructed that the leakage radiation averaged over any one hundred (100) cm² area at a distance of one meter from the source does not exceed one (1) Roentgen in an hour when the tube is operated at its maximum rated continuous current for the maximum rated tube potential.

7.2.86.b. For x-ray therapy equipment capable of operating at five hundred (500) kVp or above, the following definition applies: An x-ray tube housing so constructed that the leakage radiation averaged over any one hundred (100) cm² area at a distance of one meter from the source does not exceed one-tenth (0.1) percent of useful beam dose rate at one meter from the source for any of its operating conditions.

7.2.87. Tomogram - the depiction of the x-ray attenuation properties of a Section through the body.

7.2.88. Tube Housing Assembly - the tube housing with tube installed. It includes high-voltage or filament transformers and other appropriate elements when such are contained within the tube housing.

7.2.89. Tube Rating Chart - the set of curves which specify the rated limits of operation of the tube in terms of the technique factors.

7.2.90. Useful Beam - the radiation which passes through the tube housing port and the aperture of the beam-limiting device when the exposure switch or timer is activated.

7.2.91. Variable-aperture Beam-limiting Device - a beam-limiting device which has capacity for stepless adjustment of the x-ray field size at a given SID.

7.2.92. Visible Area - that portion of the input surface of the image receptor over which incident x-ray photons are producing a visible image.

7.2.93. X-ray Exposure Control - a device, switch, button or other similar means by which an operator initiates or terminates the radiation exposure. The x-ray exposure control may include such associated equipment as timers and back-up timers.

7.2.94. X-ray Equipment - an x-ray system, subsystem, or component thereof. Types of x-ray equipment are as follows:

7.2.94.a. Mobile X-ray Equipment - x-ray equipment mounted on a permanent base with wheels or casters for moving while completely assembled.

7.2.94.b. Portable X-ray Equipment - x-ray equipment designed to be hand-carried.

7.2.94.c. Stationary X-ray Equipment - x-ray equipment which is installed in a fixed location.

7.2.95. X-ray Field - that area of the intersection of the useful beam and any one of the set of planes parallel to and including the plane of the image receptor, whose perimeter is the locus of points at which the exposure rate is one-fourth of the maximum in the intersection.

7.2.96. X-ray High-voltage Generator - a device which transforms electrical energy from the potential supplied by the x-ray control to the tube operating potential. The device may also include means for transforming alternating current to direct current, filament transformers for the x-ray tubes, high-voltage switches, electrical protective devices, and other appropriate elements.

7.2.97. X-ray System - an assemblage of components for the controlled production of x-rays. It includes minimally an x-ray high-voltage generator, an x-ray control, a tube housing assembly, a beam-limiting device, and the necessary supporting structures. Additional components which function with the system are considered integral parts of the system.

7.2.98. X-ray Table - a patient support device with its patient support structure (tabletop) interposed between the patient and the image receptor during radiography or fluoroscopy. This includes, but is not limited to, any stretcher equipped with a radiolucent panel and any Table equipped with a cassette tray (or bucky), cassette tunnel, image intensifier, or spot-film device beneath the Tabletop.

7.2.99. X-ray Tube - any electron tube which is designed for the conversion of electrical energy into x-ray energy.

7.3. Use of X-Ray Equipment in the Healing Arts and Administrative Requirements

7.3.a. Radiation Safety Requirements The registrant shall be responsible for directing the operation of the x-ray systems under his administrative control. The registrant or the registrant's agent shall assure that the requirements of this rule are met in the operation of the x-ray systems.

7.3.a.1. An x-ray system which does not meet the provisions of this rule shall not be operated for diagnostic purposes.

7.3.a.2. Individuals who will be operating the x-ray systems shall be adequately instructed in the safe operating procedures and be competent in the safe use of the equipment. See Table 64-23 P for a list of subject matters pertinent to this requirement. The agency may use interview, observation or testing to determine compliance.

7.3.a.3. A chart shall be provided in the vicinity of the diagnostic x-ray system's control panel which specifies, for all examinations performed with that system, the following information:

7.3.a.3.A. Patient's body part and anatomical size, or body part thickness, or age (for pediatrics), versus technique factors to be utilized;

7.3.a.3.B. Type and size of the film or film-screen combination to be used;

7.3.a.3.C. Type and focal distance of the grid to be used, if any;

7.3.a.3.D. Source to image receptor distance to be used (except for dental intra-oral radiography);

7.3.a.3.E. Type and location of placement of patient shielding (e.g., gonad, etc.) to be used; and

7.3.a.3.F. For mammography, indication of kVp or target or filter combination.

7.3.a.4. The registrant shall create and make available to x-ray operators written safety policies, including patient holding and any restrictions of the operating technique required for the safe operation of the particular x-ray system. The operator shall be able to demonstrate familiarity with these procedures.

7.3.a.5. Except for patients who cannot be moved out of the room, only the staff, ancillary personnel or other persons required for the medical procedure or training shall be in the room during the radiographic exposure. Other than the patient being examined:

7.3.a.5.A. All individuals shall be positioned such that no part of the body will be struck by the useful beam unless protected by not less than five-tenths (0.5) millimeter lead equivalent material;

7.3.a.5.B. The x-ray operator, other staff, ancillary personnel, and other persons required for the medical procedure shall be protected from the direct scatter radiation by protective aprons or whole body protective barriers of not less than twenty five one-hundredths (0.25) millimeter lead equivalent material;

7.3.a.5.C. Human patients who cannot be removed from the room shall be protected from the direct scatter radiation by whole body protective barriers of not less than twenty five one-hundredths (0.25) millimeter lead equivalent material or shall be so positioned that the nearest portion of the body is at least two (2) meters from both the tube head and the nearest edge of the image receptor.

7.3.a.6. Gonad shielding of not less than five-tenths (0.5) millimeter lead equivalent material shall be used for human patients, who have not passed the reproductive age, during radiographic procedures in which the gonads are in the useful beam, except for cases in which this would interfere with the diagnostic procedure.

7.3.a.7. Individuals shall not be exposed to the useful beam except for healing arts purposes and unless such exposure has been authorized by a licensed practitioner of the healing arts. This provision specifically prohibits deliberate exposure for the following purposes:

7.3.a.7.A. Exposure of an individual for training, demonstration, or other non-healing arts purposes; and

7.3.a.7.B. Exposure of an individual for the purpose of healing arts screening except as authorized by Paragraph 7.3.a.11.

7.3.a.8. When a patient or film must be provided with auxiliary support during a radiation exposure:

7.3.a.8.A. Mechanical holding devices shall be used when the technique permits. The written safety procedures, required by Paragraph 7.3.a.5., shall list individual projections where holding devices cannot be utilized;

7.3.a.8.B. Written safety procedures, as required by Paragraph 7.3.a.5., shall indicate the requirements for selecting a holder and the procedure the holder shall follow;

7.3.a.8.C. The human holder shall be instructed in personal radiation safety and protected as required by Paragraph 7.3.a.5.;

7.3.a.8.D. No individual shall be used routinely to hold film or patients;

7.3.a.8.E. In those cases where the patient must hold the film, except during intraoral examinations, any portion of the body other than the area of clinical interest struck by the useful beam shall be protected by not less than five-tenths (0.5) millimeter lead equivalent material; and

7.3.a.8.F. Each facility shall have leaded aprons and gloves available in sufficient numbers to provide protection to all personnel who are involved with x-ray operations and who are otherwise not shielded.

7.3.a.9. Procedures and auxiliary equipment designed to minimize patient and personnel exposure commensurate with the needed diagnostic information shall be utilized.

7.3.a.9.A. The speed of the screen and film combinations used shall be the fastest speed consistent with the diagnostic objective of the examinations. Film cassettes without intensifying screens shall not be used for any routine diagnostic radiological imaging, with the exception of veterinary radiography and standard film packets for intra-oral use in dental radiography.

7.3.a.9.B. The radiation exposure to the patient shall be the minimum exposure required to produce images of good diagnostic quality.

7.3.a.9.C. Portable or mobile x-ray equipment shall be used only for examinations where it is impractical to transfer the patients to a stationary x-ray installation.

7.3.a.9.D. X-ray systems subject to Subsection 7.8. shall not be utilized in procedures where the source to patient distance is less than thirty (30) centimeters, except for veterinary systems.

7.3.a.9.E. If grids are used between the patient and the image receptor to decrease scatter to the film and improve contrast, the grid shall:

7.3.a.9.E.1. Be positioned properly, i.e., tube side facing the right direction, and grid centered to the central ray;

7.3.a.9.E.2. If of the focused type, be of the proper focal distance for the SIDs being used.

7.3.a.10. All individuals who are associated with the operation of an x-ray system are subject to the requirements of Subsections 6.5., 6.9., 6.11. and 6.12. of this rule.

7.3.a.11. Healing Arts Screening. Any person proposing to conduct a healing arts program shall not initiate such a program without prior approval of the agency. When requesting such approval, that person shall submit the information outlined in Table 64-23 T. If any information submitted to the agency becomes invalid or outdated, the agency shall be immediately notified.

7.3.a.12. Information and Maintenance Record and Associated Information. The registrant shall maintain the following information for each x-ray system for inspection by the agency:

7.3.a.12.A. Model and serial numbers of all major components, and user's manuals for those components;

7.3.a.12.B. Tube rating charts and cooling curves;

7.3.a.12.C. Records of surveys, calibrations, maintenance, and modifications performed on the x-ray system or systems; and

7.3.a.12.D. A copy of all correspondence with this agency regarding that x-ray system.

7.3.a.13. X-Ray Utilization Log. Except for veterinary facilities, each facility shall maintain a record containing the patient's name, the type of examinations, and the dates the examinations were performed. When the patient or film must be provided with human auxiliary support, the name of the human holder shall be recorded.

7.3.b. X-Ray Film Processing Facilities and Practices.

7.3.b.1. Each installation using a radiographic x-ray system and using analog image receptors (e.g. radiographic film) shall have available suitable equipment for handling and processing radiographic film in accordance with the following provisions:

7.3.b.1.A. Manually developed film:

7.3.b.1.A.1. Processing tanks shall be constructed of mechanically rigid, corrosion resistant material; and

7.3.b.1.A.2. The temperature of solutions in the tanks shall be maintained within the range of sixty (60) ^oF to eighty (80) ^oF (sixteen [16] ^oC to twenty seven [27] ^oC). Film shall be developed in accordance with the time-temperature relationships recommended by the film manufacturer, or, in the absence of such recommendations, with the time-temperature chart in Table 64-23 M.

7.3.b.1.A.3. Devices shall be utilized which will indicate the actual temperature of the developer and signal the passage of a preset time appropriate to the developing time required.

7.3.b.1.B. Automatic processors and other closed processing systems:

7.3.b.1.B.1. Films shall be developed in accordance with the time-temperature relationships recommended by the film manufacturer; in the absence of such recommendations, the film shall be developed using Table 64-23 N.

7.3.b.1.B.2. The specified developer temperature and immersion time shall be posted in the darkroom or on the automatic processor.

7.3.b.1.B.3. Processing deviations from the requirements of Paragraph 7.3.b.1. shall be documented by the registrant in such manner that the requirements are shown to be met or exceeded (e.g., extended processing, and special rapid chemistry).

7.3.b.2. Other Requirements.

7.3.b.2.A. Pass boxes, if provided, shall be so constructed as to exclude light from the darkroom when cassettes are placed in or removed from the boxes, and shall incorporate adequate shielding from stray radiation to prevent exposure of undeveloped film.

7.3.b.2.B. The darkroom shall be light tight and use proper safelighting such that any film type in use exposed in a cassette to x-radiation sufficient to produce an optical density from one (1) to two (2) when processed shall not suffer an increase in density greater than one-tenth (0.1) (five one-hundredths [0.05] for mammography) when exposed in the darkroom for two (2) minutes with all safelights on. If used, daylight film handling boxes shall preclude fogging of the film.

7.3.b.2.C. Darkrooms typically used by more than one individual shall be provided a method to prevent accidental entry while undeveloped films are being handled or processed.

7.3.b.2.D. Film shall be stored in a cool, dry place and shall be protected from exposure to stray radiation. Film in open packages shall be stored in a light tight container.

7.3.b.2.E. Film cassettes and intensifying screens shall be inspected periodically and shall be cleaned and replaced as necessary to best assure radiographs of good diagnostic quality.

7.3.b.2.F. Outdated x-ray film shall not be used for diagnostic radiographs, unless the film has been stored in accordance with the manufacturer's recommendations and a sample of the film passes a sensitometric test for normal ranges of base plus fog and speed.

7.3.b.2.G. Film developing solutions shall be prepared in accordance with the directions given by the manufacturer, and shall be maintained in strength by replenishment or renewal so that full development is accomplished within the time specified by the manufacturer.

7.4. Shielding Plan Review.

7.4.a. Prior to construction, the floor plans, shielding specifications and equipment arrangement of all new installations, or modifications of existing installations, utilizing ionizing radiation machines shall be submitted to the agency for review and approval. The required information is denoted in Tables 64-23 Q and R.

7.4.b. The agency may require the applicant to utilize the services of a qualified expert to determine the shielding requirements prior to the plan review and approval.

7.4.c. The approval of such plans shall not preclude the requirement of additional modifications should a subsequent analysis of operating conditions indicate the possibility of an individual receiving a dose in excess of the limits prescribed in Subsections 6.5., 6.9. - 6.12., 6.13. and 6.14. of this rule.

7.4.d. After installation of a radiation machine, the registrant shall maintain for inspection by the agency:

7.4.d.1. The maximum rated technique factors of each machine;

7.4.d.2. A scale drawing of the room in which a stationary radiation machine system is located with such drawing indicating the use of areas adjacent to the room and an estimation of the extent of occupancy by an individual in such areas. In addition, the drawing shall include:

7.4.d.2.A. The results of a survey for radiation levels present at the operator's position and at pertinent points outside the room at specified test conditions; or

7.4.d.2.B. The Type And thickness of materials, or lead equivalency, of each protective barrier.

7.5. Prohibited Use - No registrant shall operate or permit the operation of x-ray equipment unless the equipment and installation meet the applicable requirements of this rule.

7.6. General Requirements for All Diagnostic X-Ray Systems. In addition to other requirements of this Section, all diagnostic x-ray systems shall meet the following requirements:

7.6.a. Warning Label. The control panel containing the main power switch shall bear the warning statement, legible and accessible to view: "WARNING: This x-ray unit may be dangerous to patient and operator unless safe exposure factors and operating instructions are observed."

7.6.b. Battery Charge Indicator. On battery-powered x-ray generators, visual means shall be provided on the control panel to indicate whether the battery is in a state of charge adequate for proper operation.

7.6.c. Leakage Radiation from the Diagnostic Source Assembly. The leakage radiation from the diagnostic source assembly measured at a distance of 1 meter in any direction from the source shall not exceed twenty five and eight-tenths (25.8) :C/kg (one hundred [100 milliroentgens] in one (1) hour when the x-ray tube is operated at its leakage technique factors. Compliance shall be determined by measurements averaged over an area of one hundred (100) square centimeters with no linear dimension greater than twenty (20) centimeters.

7.6.d. Radiation from Components Other Than the Diagnostic Source Assembly. The radiation emitted by a component other than the diagnostic source assembly shall not exceed five-tenths (0.5) :C/kg (two [2] milliroentgens) in one (1) hour at five (5) centimeters from any accessible surface of the component when it is operated in an assembled x-ray system under any conditions for which it was designed. Compliance shall be determined by measurements averaged over an area of one hundred (100) square centimeters with no linear dimension greater than twenty (20) centimeters.

7.6.e. Beam Quality.

7.6.e.1. Half-Value Layer.

7.6.e.1.A. The half-value layer of the useful beam for a given x-ray tube potential shall not be less than the values shown in Table 64-23 O. If it is necessary to determine such half-value layer at an x-ray tube potential which is not listed in Table I, linear interpolation or extrapolation may be made.

7.6.e.1.B. For capacitor energy storage equipment, compliance with the requirements of Paragraph 7.6.e.1. shall be determined with the system fully charged and a setting of ten (10) mAs for each exposure.

7.6.e.1.C. The required minimal half-value layer of the useful beam shall include the filtration contributed by all materials which are permanently between the source and the patient.

7.6.e.2. Filtration Controls. For x-ray systems which have variable kVp and variable filtration for the useful beam, a device shall link the kVp selector with the filter or filters and shall prevent an exposure unless the minimum amount of filtration necessary to produce the HVL required by Paragraph 7.6.e.1. is in the useful beam for the given kVp which has been selected.

7.6.f. Multiple Tubes. Where two or more radiographic tubes are controlled by one exposure switch, the tube or tubes which have been selected shall be clearly indicated prior to initiation of the exposure. This indication shall be both on the x-ray control panel and at or near the tube housing assembly which has been selected.

7.6.g. Mechanical Support of Tube Head. The tube housing assembly supports shall be adjusted such that the tube housing assembly will remain stable during an exposure unless tube housing movement is a designed function of the x-ray system.

7.6.h. Technique Indicators.

7.6.h.1. The technique factors to be used during an exposure shall be indicated before the exposure begins. If automatic exposure controls are used, the technique factors which are set prior to the exposure shall be indicated.

7.6.h.2. The requirement of Paragraph 7.6.h.1. may be met by permanent markings on equipment having fixed technique factors. Indication of technique factors shall be visible from the operator's position except in the case of spot films made by the fluoroscopist.

7.6.i. Maintaining Compliance. Diagnostic x-ray systems and their associated components used on humans and certified pursuant to the federal x-ray equipment performance standard (21 CFR Part 1020) shall be maintained in compliance with applicable requirements of that standard.

7.6.j. Locks. All position locking, holding, and centering devices on x-ray system components and systems shall function as intended.

7.7. Fluoroscopic X-Ray Systems. All fluoroscopic x-ray systems used shall be image intensified and meet the following requirements:

7.7.a. Limitation of Useful Beam.

7.7.a.1. Primary Barrier

7.7.a.1.A. The fluoroscopic imaging assembly shall be provided with a primary protective barrier which intercepts the entire cross Section of the useful beam at any SID.

7.7.a.1.B. The x-ray tube used for fluoroscopy shall not produce x-rays unless the barrier is in position to intercept the entire useful beam.

7.7.a.2. Fluoroscopic Beam Limitation.

7.7.a.2.A. For certified fluoroscopic systems with or without a spot film device, neither the length nor the width of the x-ray field in the plane of the image receptor shall exceed that of the visible area of the image receptor by more than three (3) percent of the SID. The sum of the excess length and the excess width shall be no greater than four (4) percent of the SID.

7.7.a.2.B. For uncertified fluoroscopic systems with a spot film device, the x-ray beam with the shutters fully opened (during fluoroscopy or spot filming) shall be no larger than the largest spot film size for which the device is designed. Measurements shall be made at the minimum SID available but at no less than twenty (20) centimeters Table top to the film plane distance.

7.7.a.2.C. For uncertified fluoroscopic systems without a spot film device, the requirements of Subparagraph 7.7.a.2.A. apply.

7.7.a.2.D. Other Requirements for Fluoroscopic Beam Limitation:

7.7.a.2.D.1. Means shall be provided to permit further limitation of the field. Beam-limiting devices manufactured after May 22, 1979, and incorporated in equipment with a variable SID or a visible area of greater than three hundred (300) square centimeters shall be provided with means for stepless adjustment of the x-ray field;

7.7.a.2.D.2. All equipment with a fixed SID and a visible area of three hundred (300) square centimeters or less shall be provided with either stepless adjustment of the x-ray field or with means to further limit the x-ray field size at the plane of the image receptor to one hundred twenty five (125) square centimeters or less;

7.7.a.2.D.3. If provided, stepless adjustment shall, at the greatest SID, provide continuous field sizes from the maximum attainable to a field size of five (5) centimeters by five (5) centimeters or less;

7.7.a.2.D.4. For equipment manufactured after February 25, 1978, when the angle between the image receptor and beam axis is variable, means shall be provided to indicate when the axis of the x-ray beam is perpendicular to the plane of the image receptor;

7.7.a.2.D.5. For non-circular x-ray fields used with circular image receptors, the error in alignment shall be determined along the length and width dimensions of the x-ray field which pass through the center of the visible area of the image receptor.

7.7.a.3. Spot-film Beam Limitation. Spot-film devices shall meet the following requirements:

7.7.a.3.A. Means shall be provided between the source and the patient for adjustment of the x-ray field size in the plane of the film to the size of that portion of the film which has been selected on the spot film selector. Such adjustment shall be automatically accomplished except when the x-ray field size in the plane of the film is smaller than that of the selected portion of the film. For spot film devices manufactured after June 21, 1979, if the x-ray field size is less than the size of the selected portion of the film, the means for adjustment of the field size shall be only at the operator's option;

7.7.a.3.B. Neither the length nor the width of the x-ray field in the plane of the image receptor shall differ from the corresponding dimensions of the selected portion of the image receptor by more than three (3) percent of the SID when adjusted for full coverage of the selected portion of the image receptor. The sum, without regard to sign, of the length and width differences shall not exceed four (4) percent of the SID;

7.7.a.3.C. It shall be possible to adjust the x-ray field size in the plane of the film to a size smaller than the selected portion of the film. The minimum field size at the greatest SID shall be equal to, or less than, five (5) centimeters by five (5) centimeters;

7.7.a.3.D. The center of the x-ray field in the plane of the film shall be aligned with the center of the selected portion of the film to within two (2) percent of the SID; and

7.7.a.3.E. On spot-film devices manufactured after February 25, 1978, if the angle between the plane of the image receptor and beam axis is variable, means shall be provided to indicate when the axis of the x-ray beam is perpendicular to the plane of the image receptor, and compliance shall be determined with the beam axis indicated to be perpendicular to the plane of the image receptor.

7.7.a.4. Override. If a means exists to override any of the automatic x-ray field size adjustments required in Paragraphs 7.7.a.2. and 3., that means:

7.7.a.4.A. Shall be designed for use only in the event of system failure;

7.7.a.4.B. Shall incorporate a signal visible at the fluoroscopist's position which will indicate whenever the automatic field size adjustment is overridden; and

7.7.a.4.C. Shall be clearly and durably labeled as follows:

FOR X-RAY FIELD

LIMITATION SYSTEM FAILURE

7.7.b. Activation of the Fluoroscopic Tube. X-ray production in the fluoroscopic mode shall be controlled by a device which requires continuous pressure by the fluoroscopist for the entire time of any exposure. When recording serial fluoroscopic images, the fluoroscopist shall be able to terminate the x-ray exposures at any time, but means may be provided to permit completion of any single exposure of the series in process.

7.7.c. Exposure Rate Limits.

7.7.c.1. Entrance Exposure Allowable Limits.

7.7.c.1.A. Fluoroscopic equipment which is provided with automatic exposure rate control shall not be operable at any combination of tube potential and current which will result in an exposure rate in excess of two and six-tenths (2.6) mC/kg (ten [10]Roentgens) per minute at the point where the center of the useful beam enters the patient, except:

7.7.c.1.A.1. During recording of fluoroscopic images; or

7.7.c.1.A.2. When an optional high level control is provided. When so provided, the equipment shall not be operable at any combination of tube potential and current which will result in an exposure rate in excess of one and three-tenths (1.3) mC/kg (five [5] Roentgens) per minute at the point where the center of the useful beam enters the patient unless the high level control is activated. Special means of activation of high level controls shall be required. The high level control shall only be operable when continuous manual activation is provided by the operator. A continuous signal audible to the fluoroscopist shall indicate that the high level control is being employed.

7.7.c.1.B. Fluoroscopic equipment which is not provided with automatic exposure rate control shall not be operable at any combination of tube potential and current which will result in an exposure rate in excess of one and three-tenths (1.3) mC/kg (five [5] Roentgens) per minute at the point where the center of the useful beam enters the patient, except:

7.7.c.1.B.1. During recording of fluoroscopic images; or

7.7.c.1.B.2. When an optional high level control is activated. Special means of activation of high level controls shall be required. The high level control shall only be operable when continuous manual activation is provided by the operator. A continuous signal audible to the fluoroscopist shall indicate that the high level control is being employed.

7.7.c.1.C. Compliance with the requirements of Subdivision 7.7.c. shall be determined as follows:

7.7.c.1.C.1. If the source is below the x-ray Table, the exposure rate shall be measured one (1) centimeter above the Tabletop or cradle;

7.7.c.1.C.2. If the source is above the x-ray Table, the exposure rate shall be measured at thirty (30) centimeters above the Tabletop with the end of the beam-limiting device or spacer positioned as closely as possible to the point of measurement;

7.7.c.1.C.3. For a C-arm type of fluoroscope, the exposure rate shall be measured thirty (30) centimeters from the input surface of the fluoroscopic imaging assembly, with the source positioned at any available SID, provided that the end of the beam-limiting device or spacer is no closer than thirty (30) centimeters from the input surface of the fluoroscopic imaging assembly;

7.7.c.1.C.4. For a lateral type fluoroscope, the exposure rate shall be measured at a point fifteen (15) centimeters from the centerline of the x-ray Table and in the direction of the x-ray source with the end of the beam-limiting device or spacer positioned as closely as possible to the point of measurement. If the Tabletop is movable, it shall be positioned as closely as possible to the lateral x-ray source, with the end of the beam-limiting device or spacer no closer than fifteen (15) centimeters to the centerline of the x-ray Table.

7.7.c.2. Periodic measurement of entrance exposure rate shall be performed by a qualified expert for both typical and maximum values as follows: 5

7.7.c.2.A. Such measurements shall be made annually or after any maintenance of the system which might affect the exposure rate;

7.7.c.2.B. Results of these measurements shall be posted where any fluoroscopist may have ready access to such results while using the fluoroscope and in the record required in Part 7.3.a.12. The measurement results shall be stated in coulombs per kilogram (Roentgens) per minute and include the technique factors used in determining such results. The name of the individual performing the measurements and the date the measurements were performed shall be included in the results;

7.7.c.2.C. Conditions of periodic measurement of typical entrance exposure rate are as follows:

7.7.c.2.C.1. The measurement shall be made under the conditions that satisfy the requirements of 7.7.c.2.C.2.;

7.7.c.2.C.2. The kVp, mA, and other selectable parameters shall be adjusted to those settings typical of clinical use on a twenty three (23) cm thick abdominal patient;

7.7.c.2.C.3. The x-ray system that incorporates automatic exposure rate control shall have sufficient attenuative material placed in the useful beam to produce a milliamperage or kilovoltage to satisfy the conditions of 7.7.c.2.C.2.;

7.7.c.2.D. Conditions of periodic measurement of maximum entrance exposure rate are as follows:

7.7.c.2.D.1. The measurement shall be made under the conditions that satisfy the requirements of 7.7.c.2.C.2.;

7.7.c.2.D.2. The kVp, mA or other selectable parameters shall be adjusted to those settings which give the maximum entrance exposure rate;

7.7.c.2.D.3. The x-ray systems that incorporates automatic exposure rate control shall have sufficient attentuative material placed in the useful beam to produce the maximum entrance exposure rate of the system.

7.7.d. Barrier Transmitted Radiation Rate Limits.

7.7.d.1. The exposure rate due to transmission through the primary protective barrier with the attenuation block in the useful beam, combined with radiation from the image intensifier, if provided, shall not exceed five-tenths (0.5) :C/kg (two [2] milliroentgens) per hour at ten (10) centimeters from any accessible surface of the fluoroscopic imaging assembly beyond the plane of the image receptor for each mC/kg (Roentgen) per minute of entrance exposure rate.

7.7.d.2. Measuring Compliance of Barrier Transmission.

7.7.d.2.A. The exposure rate due to transmission through the primary protective barrier combined with radiation from the image intensifier shall be determined by measurements averaged over an area of one hundred (100) square centimeters with no linear dimension greater than twenty (20) centimeters.

7.7.d.2.B. If the source is below the Tabletop, the measurement shall be made with the input surface of the fluoroscopic imaging assembly positioned thirty (30) centimeters above the Tabletop.

7.7.d.2.C. If the source is above the Tabletop and the SID is variable, the measurement shall be made with the end of the beam-limiting device or spacer as close to the Tabletop as it can be placed, provided that it shall not be closer than thirty (30) centimeters.

7.7.d.2.E. Movable grids and compression devices shall be removed from the useful beam during the measurement.

7.7.e. Indication of Potential and Current. During fluoroscopy and cinefluorography the kV and the mA shall be continuously indicated.

7.7.f. Source-to-Skin Distance. The SSD shall not be less than:

7.7.f.1. Thirty-eight (38) centimeters on stationary fluoroscopic systems manufactured on or after August 1, 1974;

7.7.f.2. Thirty-five and five-tenths (35.5) centimeters on stationary fluoroscopic systems manufactured prior to August 1, 1974;

7.7.f.3. Thirty (30) centimeters on all mobile fluoroscopes; or

7.7.f.4. Twenty (20) centimeters for all mobile fluoroscopes when used for specific surgical applications.

7.7.g. Fluoroscopic Timer.

7.7.g.1. Means shall be provided to preset the cumulative on-time of the fluoroscopic x-ray tube. The maximum cumulative time of the timing device shall not exceed five (5) minutes without resetting.

7.7.g.2. A signal audible to the fluoroscopist shall indicate the completion of any preset cumulative on-time. Such signal shall continue to sound while x rays are produced until the timing device is reset.

7.7.h. Control of Scattered Radiation.

7.7.h.1. Fluoroscopic Table designs when combined with procedures utilized shall be such that no unprotected part of any staff or ancillary individual's body shall be exposed to unattenuated scattered radiation which originates from under the Table. The attenuation required shall be not less than twenty five one-hundredths (0.25) millimeter lead equivalent.

7.7.h.2. Equipment configuration when combined with procedures shall be such that no portion of any staff or ancillary individual's body, except the extremities, shall be exposed to the unattenuated scattered radiation emanating from above the Tabletop unless that individual:

7.7.h.2.A. Is at least one hundred twenty (120) centimeters from the center of the useful beam; or

7.7.h.2.B. The radiation has passed through not less than twenty five (0.25) millimeter lead equivalent material including, but not limited to, drapes, bucky-slot cover panel, or self-supporting curtains, in addition to any lead equivalency provided by the protective apron referred to in Paragraph 7.3.a.5.

7.7.h.3. The agency may grant exemptions to Subdivision 7.7.h.2. where a sterile field will not permit the use of the normal protective barriers. Where the use of prefitted sterilized covers for the barriers is practical, the agency shall not permit such exemption. See Table 64-23 S for a suggested list of fluoroscopic procedures where such exemptions will be automatically granted.

7.7.i. Spot Film Exposure Reproducibility. Fluoroscopic systems equipped with spot film (radiographic) mode shall meet the exposure reproducibility requirements of Subsection 7.8.d. when operating in the spot film mode.

7.7.j. Radiation Therapy Simulation Systems. Radiation therapy simulation systems shall be exempt from all the requirements of Subsection 7.7.c. In addition, these systems shall be exempt from:

7.7.j.1. The requirements of Subsections 7.7.a. and 7.7.d. provided such systems are designed and used in such a manner that no individual other than the patient is in the x-ray room during periods of time when the system is producing x-rays; and

7.7.j.2. The requirements of Subsection 7.7.g. if such systems are provided with a means of indicating the cumulative time that an individual patient has been exposed to x-rays. Procedures shall require in such cases that the timer be reset between examinations.

7.8. Radiographic Systems Other Than Fluoroscopic, Dental Intraoral, or Computed Tomography X-Ray Systems.

7.8.a. Beam Limitation, Except Mammographic Systems. The useful beam shall be limited to the area of clinical interest. This shall be deemed to have been met if a positive beam limiting device meeting manufacturer's specifications and the requirements of Paragraph 7.8.h.2. has been properly used or if evidence of collimation is shown on at least three sides or three corners of the film (for example, projections from the shutters of the collimator, cone cutting at the corners, or borders at the film's edge).

7.8.a.1. General Purpose Stationary and Mobile X-Ray Systems, Including Veterinary Systems (Other than Portable) Installed After the Effective Date of This rule.

7.8.a.1.A. Only x-ray systems provided with means for independent stepless adjustment of at least two dimensions of the x-ray field shall be used.

7.8.a.1.B. A method shall be provided for visually defining the perimeter of the x-ray field. The total misalignment of the edges of the visually defined field with the respective edges of the x-ray field along either the length or width of the visually defined field shall not exceed two (2) percent of the distance from the source to the center of the visually defined field when the surface upon which it appears is perpendicular to the axis of the x-ray beam.

7.8.a.1.C. The agency may grant an exemption on non-certified x-ray systems to Subparagraphs 7.8.a.1.A. and B. provided the registrant makes a written application for such exemption and in that application:

7.8.a.1.C.1. Demonstrates it is impractical to comply with Subparagraphs 7.8.a.1.A. and B.; and

7.8.a.1.C.2. The purpose of Subparagraphs 7.8.a.1.A. and B. will be met by other methods.

7.8.a.2. Additional Requirements for Stationary General Purpose X-Ray Systems. In addition to the requirements of Paragraph 7.8.a.1., stationary general purpose x-ray systems, both certified and noncertified, shall meet the following requirements:

7.8.a.2.A. A method shall be provided to indicate when the axis of the x-ray beam is perpendicular to the plane of the image receptor, to align the center of the x-ray field with respect to the center of the image receptor to within two (2) percent of the SID, and to indicate the SID to within two (2) percent;

7.8.a.2.B. The beam-limiting device shall indicate numerically the field size in the plane of the image receptor to which it is adjusted; and

7.8.a.2.C. Indication of field size dimensions and SIDs shall be specified in inches or centimeters, and shall be such that aperture adjustments result in x-ray field dimensions in the plane of the image receptor which correspond to those indicated by the beam-limiting device to within two (2) percent of the SID when the beam axis is indicated to be perpendicular to the plane of the image receptor.

7.8.a.3. X-Ray Systems Designed for One Image Receptor Size. Radiographic equipment designed for only one image receptor size at a fixed SID shall be provided with means to limit the field at the plane of the image receptor to dimensions no greater than those of the image receptor, and to align the center of the x-ray field with the center of the image receptor to within two (2) percent of the SID, or shall be provided with means to both size and align the x-ray field such that the x-ray field at the plane of the image receptor does not extend beyond any edge of the image receptor.

7.8.a.4. X-Ray Systems Other Than Those Described in Subparagraphs 7.8.a.1.A., B. and C. and Veterinary Systems Installed Prior to the Effective Date of This rule and all Portable Veterinary X-Ray Systems.

7.8.a.4.A. Means shall be provided to limit the x-ray field in the plane of the image receptor so that such field does not exceed each dimension of the image receptor by more than two (2) percent of the SID when the axis of the x-ray beam is perpendicular to the plane of the image receptor.

7.8.a.4.B. Means shall be provided to align the center of the x-ray field with the center of the image receptor to within two (2) percent of the SID, or means shall be provided to both size and align the x-ray field such that the x-ray field at the plane of the image receptor does not extend beyond any edge of the image receptor. Compliance shall be determined with the axis of the x-ray beam perpendicular to the plane of the image receptor.

7.8.a.4.C. Subparagraph 7.8.a.4.A and B. may be met with a system that meets the requirements for a general purpose x-ray system as specified in Paragraph 7.8.a.1. or, when alignment means are also provided, may be met with either:

7.8.a.4.C.1. An assortment of removable, fixed-aperture, beam-limiting devices sufficient to meet the requirement for each combination of image receptor size and SID for which the unit is designed with each such device having clear and permanent markings to indicate the image receptor size and SID for which it is designed; or

7.8.a.4.C.2. A beam-limiting device having multiple fixed apertures sufficient to meet the requirement for each combination of image receptor size and SID for which the unit is designed. Permanent, clearly legible markings shall indicate the image receptor size and SID for which each aperture is designed and shall indicate which aperture is in position for use.

7.8.b. Radiation Exposure Control.

7.8.b.1. Exposure Initiation. Means shall be provided to initiate the radiation exposure by a deliberate action on the part of the operator, such as the depression of a switch. Radiation exposure shall not be initiated without such an action. In addition, it shall not be possible to initiate an exposure when the timer is set to a "zero" or "off" position if either position is provided.

7.8.b.2. Exposure Indication. Means shall be provided for visual indication observable at or from the operator's protected position whenever x-rays are produced. In addition, a signal audible to the operator shall indicate that the exposure has terminated.

7.8.b.3. Exposure Termination. Means shall be provided to terminate the exposure at a preset time interval, preset product of current and time, a preset number of pulses, or a preset radiation exposure to the image receptor. Except for dental panoramic systems, termination of an exposure shall cause automatic resetting of the timer to its initial setting or to "zero."

7.8.b.3.A. Manual Exposure Control. An x-ray control shall be incorporated into each x-ray system such that an exposure can be terminated by the operator at any time except for:

7.8.b.3.A.1. Exposure of one-half (½) second or less; or

7.8.b.3.A.2. During serial radiography when means shall be provided to permit completion of any single exposure of the series in process.

7.8.b.3.B. Automatic Exposure Controls. When an automatic exposure control is provided:

7.8.b.3.B.1. Indication shall be made on the control panel when this mode of operation is selected;

7.8.b.3.B.2. If the x-ray tube potential is equal to or greater than fifty (50) kVp, the minimum exposure time for field emission equipment rated for pulsed operation shall be equal to or less than a time interval equivalent to two (2) pulses;

7.8.b.3.B.3. The minimum exposure time for all equipment other than that specified in Part 7.8.b.3.B.2. shall be equal to or less than one-sixtieth (1/60) second or a time interval required to deliver five (5) mAs, whichever is greater;

7.8.b.3.B.4. Either the product of peak x-ray tube potential, current, and exposure time shall be limited to not more than sixty (60) kWs per exposure, or the product of x-ray tube current and exposure time shall be limited to not more than six hundred (600) mAs per exposure except that, when the x-ray tube potential is less than fifty (50) kVp, the product of x-ray tube current and exposure time shall be limited to not more than two thousand (2000) mAs per exposure; and

7.8.b.3.B.5. A visible signal shall indicate when an exposure has been terminated at the limits required by Part 7.8.b.3.B.4., and manual resetting shall be required before further automatically timed exposures can be made.

7.8.b.4. Exposure Duration (Timer) Linearity. For systems having independent selection of exposure time settings, the average ratios (X_i) of exposure to the indicated timer setting, in units of C kg^-1s^-1 (mR/s), obtained at any two clinically used timer settings shall not differ by more than one-tenth (0.10) times their sum. This is written as:

(X₁ - X₂) # 0.1 (X₁ + X₂)

where X₁ and X₂ are the average C kg^-1s^-1 (mR/s) values.

7.8.b.5. Exposure Control Location. The x-ray exposure control shall be so placed that the operator can view the patient while making any exposure.

7.8.b.6. Operator Protection, Except Veterinary Systems.

7.8.b.6.A. Stationary Systems. Stationary x-ray systems shall be required to have the x-ray control permanently mounted in a protected area so that the operator is required to remain in that protected area during the entire exposure.

7.8.b.6.B. Mobile and Portable Systems. Mobile and portable x-ray systems which are:

7.8.b.6.B.1. Used continuously for greater than one week in the same location, i.e., a room or suite, shall meet the requirements of Subparagraph 7.8.b.6.A.;

7.8.b.6.B.2. Used for less than one week at the same location shall be provided with either a protective barrier at least two (2) meters six and one-half (six [6.5] feet) high for operator protection during exposures, or means shall be provided to allow the operator to be at least two and seven-tenths (2.7) meters (nine [9] feet) from the tube housing assembly during the exposure.

7.8.b.7. Operator Protection for Veterinary Systems. All stationary, mobile or portable x-ray systems used for veterinary work shall be provided with either a two (2) meter (six and one-half [6.5] feet) high protective barrier for operator protection during exposures, or shall be provided with means to allow the operator to be at least two and seven-tenths (2.7) meters (nine [9] feet) from the tube housing assembly during exposures.

7.8.c. Source-to-Skin Distance. All mobile or portable radiographic systems shall be provided with means to limit the source-to-skin distance to equal to or greater than thirty (30) centimeters, except for veterinary systems.

7.8.d. Exposure Reproducibility. When all technique factors are held constant, including control panel selections associated with automatic exposure control systems, the coefficient of variation of exposure for both manual and automatic exposure control systems shall not exceed five one-hundredths (0.05). This requirement applies to clinically used techniques.

7.8.e. Radiation from Capacitor Energy Storage Equipment in Standby Status. Radiation emitted from the x-ray tube when the system is fully charged and the exposure switch or timer is not activated shall not exceed a rate of five-tenths (0.5) :C/kg (two [2] milliroentgens) per hour at five (5) centimeters from any accessible surface of the diagnostic source assembly, with the beam-limiting device fully open.

7.8.f. Accuracy. Deviation of measured technique factors from indicated values of kVp and exposure time shall not exceed the limits specified for that system by its manufacturer. In the absence of manufacturer's specifications, the deviation shall not exceed ten (10) percent of the indicated value for kVp and [20] percent for time.

7.8.g. mA/mAs Linearity. The following requirements apply when the equipment is operated on a power supply as specified by the manufacturer for any fixed x-ray tube potential within the range of forty (40) percent to one hundred (100) percent of the maximum rated:

7.8.g.1. Equipment Having Independent Selection of X-Ray Tube Current (mA). The average ratios (X_i) of exposure to the indicated milliampere-seconds product C kg^-1 mAs^-1 (or mR/mAs) obtained at any two consecutive tube current settings shall not differ by more than one-tenth (0.10) times their sum:

X₁-X₂ 0.10 (X₁+X₂)

where X₁ and X₂ are the average values obtained at each of two consecutive tube current settings, or at two settings differing by no more than a factor of two (2) where the tube current selection is continuous.

7.8.g.2. Equipment Having a Combined X-Ray Tube Current-Exposure Time Product (mAs) Selector, But Not a Separate Tube Current (mA) Selector. The average ratios (X_i) of exposure to the indicated milliampere-seconds product, in units of C kg^-1 mAs^-1 (or mR/mAs), obtained at any two consecutive mAs selector settings shall not differ by more than one-tenth (0.10) times their sum:

X₁-X₂ 0.10 (X₁ +X₂)

where X₁ and X₂ are the average values obtained at any two mAs selector settings, or at two settings differing by no more than a factor of two (2) where the mAs selector provides continuous selection.

7.8.g.3. Measuring Compliance. Determination of compliance shall be based on ten (10) exposures taken within a time period of one hour, at each of the two settings. These two settings may include any two focal spot sizes except where one is equal to or less than forty five one-hundredths (0.45) millimeters and the other is greater than forty five one-hundredths (0.45) millimeters. For purposes of this requirement, focal spot size is the nominal focal spot size specified by the x-ray tube manufacturer.

7.8.h. Additional Requirements Applicable to Certified Systems Only. Diagnostic x-ray systems incorporating one or more certified component or components shall be required to comply with the following additional require mentor requirements which relate to that certified component or components.

7.8.h.1. Beam Limitation for Stationary and Mobile General Purpose X-Ray Systems.

7.8.h.1.A. There shall be provided a means of stepless adjustment of the size of the x-ray field. The minimum field size at an SID of one hundred (100) centimeters shall be equal to or less than five (5) centimeters by five (5) centimeters.

7.8.h.1.B. When a light localizer is used to define the x-ray field, it shall provide an average illumination of not less than one hundred sixty (160) lux or fifteen (15) footcandles at one hundred (100) centimeters or at the maximum SID, whichever is less. The average illumination shall be based upon measurements made in the approximate center of each quadrant of the light field. Radiation therapy simulation systems manufactured on and after May 27, 1980, are exempt from this requirement.

7.8.h.1.C. The edge of the light field at one hundred (100) centimeters or at the maximum SID, whichever is less, shall have a contrast ratio, corrected for ambient lighting, of not less than four (4) in the case of beam-limiting devices designed for use on stationary equipment, and a contrast ratio of not less than three (3) in the case of beam-limiting devices designed for use on mobile equipment. The contrast ratio is defined as I₁/I₂ where I₁ is the illumination three (3) millimeters from the edge of the light field toward the center of the field; and I₂ is the illumination three (3) millimeters from the edge of the light field away from the center of the field. Compliance shall be determined with a measuring instrument aperture of one (1) millimeter in diameter.

7.8.h.2. Beam Limitation and Alignment on Stationary General Purpose X-Ray Systems Equipped with PBL. If PBL is being used, the following requirements shall be met:

7.8.h.2.A. PBL shall prevent the production of x-rays when:

7.8.h.2.A.1. Either the length or width of the x-ray field in the plane of the image receptor differs, except as permitted by Subparagraph 7.8.h.2.C., from the corresponding image receptor dimensions by more than three (3) percent of the SID; or

7.8.h.2.A.2. The sum of the length and width differences as stated in Part 7.8.h.2.A.1. without regard to sign exceeds four (4) percent of the SID;

7.8.h.2.B. Compliance with Subparagraph 7.8.h.2.A. shall be determined when the equipment indicates that the beam axis is perpendicular to the plane of the image receptor. Compliance shall be determined no sooner than five (5) seconds after insertion of the image receptor;

7.8.h.2.C. The PBL system shall be capable of operation, at the discretion of the operator, such that the size of the field may be made smaller than the size of the image receptor through stepless adjustment of the field size. The minimum field size at an SID of one hundred (100) centimeters shall be equal to or less than five (5) centimeters by five (5) centimeters;

7.8.h.2.D. The PBL system shall be designed such that if a change in image receptor does not cause an automatic return to PBL function as described in Subparagraph 7.8.h.2.A., then any change of image receptor size or SID must cause the automatic return.

7.8.h.3. Beam Limitation for Portable X-Ray Systems. Beam limitation for portable x-ray systems shall meet the beam limitation requirements of Paragraphs 7.8.a.1. or 7.8.h.2.

7.8.i. Tube Stands for Portable X-Ray Systems. A tube stand or other mechanical support shall be used for portable x-ray systems, so that the x-ray tube housing assembly need not be hand-held during exposures.

7.9. Intraoral Dental Radiographic Systems. In addition to the provisions of Subsections 7.3 and 7.4. the requirements of Subsection 7.9. apply to x-ray equipment and associated facilities used for dental radiography. Requirements for extraoral dental radiographic systems are covered in Subsection 7.8. Only systems meeting the requirements of Subsection 7.9. shall be used.

7.9.a. Source-to-Skin Distance (SSD). X-ray systems designed for use with an intraoral image receptor shall be provided with means to limit SSD, to not less than:

7.9.a.1. Eighteen (18) centimeters if operable above fifty (50) kVp; or

7.9.a.2. Ten (10) centimeters if operable at fifty (50) kVp only.

7.9.b. Beam Limitation. Radiographic systems designed for use with an intraoral image receptor shall be provided with means to limit the x-ray beam such that the beam at the minimum SSD shall be containable in a circle having a diameter of no more than seven (7) centimeters.

7.9.c. Radiation Exposure Control.

7.9.c.1. Exposure Initiation.

7.9.c.1.A. Means shall be provided to initiate the radiation exposure by a deliberate action on the part of the operator, such as the depression of a switch. Radiation exposure shall not be initiated without such an action; and

7.9.c.1.B. It shall not be possible to make an exposure when the timer is set to a "zero" or "off" position if either position is provided.

7.9.c.2. Exposure Indication. Means shall be provided for visual indication observable at or from the operator's protected position whenever x-rays are produced. In addition, a signal audible to the operator shall indicate that the exposure has terminated.

7.9.c.3. Exposure Termination.

7.9.c.3.A. Means shall be provided to terminate the exposure at a preset time interval, preset product of current and time, a preset number of pulses, or a preset radiation exposure to the image receptor.

7.9.c.3.B. An x-ray exposure control shall be incorporated into each x-ray system such that an exposure can be terminated by the operator at any time, except for exposures of one-half (½) second or less.

7.9.c.3.C. Termination of an exposure shall cause automatic resetting of the timer to its initial setting or to "zero."

7.9.c.4. Exposure Duration (Timer) Linearity. For systems having independent selection of exposure time settings, the average ratios (X_i) of exposure to the indicated timer setting, in units of C kg^-1 s^-1 (mR/s), obtained at any two clinically used timer settings shall not differ by more than one-tenth (0.10) times their sum. This is written as:

(X₁ - X₂) # 0.1 (X₁ + X₂)

where X₁ and X₂ are the average values.

7.9.c.5. Exposure Control Location and Operator Protection.

7.9.c.5.A. Stationary x-ray systems installed after the effective date of this rule shall be required to have the x-ray exposure control permanently mounted in a protected area, so that the operator is required to remain in that protected area during the entire exposure; and

7.9.c.5.B. Mobile and portable x-ray systems which are:

7.9.c.5.B.1. Used for greater than one week in the same location, i.e., a room or suite, shall meet the requirements of Subparagraph 7.9.c.5.a.;

7.9.c.5.B.2. Used for less than one week in the same location shall be provided with either a protective barrier at least two (2) meters (six and five-tenths [6.5] feet) high for operator protection, or means to allow the operator to be at least two and seven-tenths (2.7) meters (nine [9] feet) from the tube housing assembly while making exposures.

7.9.d. Reproducibility. When the equipment is operated on an adequate power supply as specified by the manufacturer, the estimated coefficient of variation of radiation exposures shall be no greater than five one-hundredths (0.05), for any specific combination of selected technique factors.

7.9.e. mA/mAs Linearity. The following requirements apply when the equipment is operated on a power supply as specified by the manufacturer for any fixed x-ray tube potential within the range of forty (40) percent to one hundred (100) percent of the maximum rated.

7.9.e.1. Equipment Having Independent Selection of X-Ray Tube Current (mA). The average ratios (X_i) of exposure to the indicated milliampere-seconds product, in units of C kg^-1 mAs^-1 (or mR/mAs), obtained at any two consecutive tube current settings shall not differ by more than one-tenth (0.10) times their sum:

X₁ - X₂ 0.10 (X₁+X₂)

7.9.e.2. Equipment Having a Combined X-Ray Tube Current-Exposure Time Product (mAs) Selector, But Not a Separate Tube Current (mA) Selector. The average ratios (X_i) of exposure to the indicated milliampere-seconds product, in units of C kg^-1 mAs^-1 (or mR/mAs), obtained at any two consecutive mAs selector settings shall not differ by more than one-tenth (0.10) times their sum:

X₁ - X₂ 0.10 (X₁ +X₂)

7.9.e.3. Measuring Compliance. Determination of compliance shall be based on ten (10) exposures taken within a time period of one hour, at each of the two settings. These two settings may include any two focal spot sizes except where one is equal to or less than forty five one-hundredths (0.45) millimeters and the other is greater than forty five One-hundredths (0.45) millimeters. For purposes of this requirement, focal spot size is the nominal focal spot size specified by the x-ray tube manufacturer.

7.9.f. Accuracy. Deviation of technique factors from indicated values for kVp and exposure time (if time is independently selectable) shall not exceed the limits specified for that system by its manufacturer. In the absence of manufacturer's specifications the deviation shall not exceed ten (10) percent of the indicated value for kVp and twenty (20) percent for time.

7.9.g. kVp Limitations. Dental x-ray machines with a nominal fixed kVp of less than fifty (50) kVp shall not be used to make diagnostic dental radiographs of humans.

7.9.h. Administrative Controls.

7.9.h.1. Patient and film holding devices shall be used when the techniques permit.

7.9.h.2. The tube housing and PID shall not be hand-held during an exposure.

7.9.h.3. The x-ray system shall be operated in such a manner that the useful beam at the patient's skin does not exceed the requirements of Paragraph 7.9.2.

7.9.h.4. Fluoroscopy without image intensification shall not be used in dental examinations.

7.9.h.5. The tube head shall remain stationary when placed in the exposure position.

7.10. Computed Tomography X-Ray Systems.

7.10.a. Definitions. In addition to the definitions provided in Section 3. and Subsection 7.2. of this rule, the following definitions shall be applicable to Subsection 7.10.:

7.10.a.1. Computed Tomography Dose Index - the integral from -7T to +7T of the dose profile along a line perpendicular to the tomographic plane divided by the product of the nominal tomographic Section thickness and the number of tomograms produced in a single scan, that is:

Click Here To View Image

where:

z = Position along a line perpendicular to the tomographic plane;

D(z) = Dose at position z;

T = Nominal tomographic Section thickness;

n = Number of tomograms produced in a single scan.

This definition assumes that the dose profile is centered around z=0 and that, for a multiple tomogram system, the scan increment between adjacent scans is nT.

7.10.a.2. Contrast Scale - the change in the linear attenuation coefficient per ctn relative to water, that is:

Click Here To View Image

where:

mu SUB FUNC x = Linear attenuation coefficient of the material of interest;

mu SUB FUNC w = Linear attenuation coefficient of water;

{ FUNC OVERLINE CTN } SUB FUNC x = of the material of interest;

{ FUNC OVERLINE CTN } SUB FUNC w = of water.

7.10.a.3. CS - Contrast Scale.

7.10.a.4. CT Conditions of Operation - all selectable parameters governing the operation of a CT x-ray system including, but not limited to, nominal tomographic Section thickness, filtration, and the technique factors as defined in Subsection 7.2.

7.10.a.5. CTDI - Computed Tomography Dose ID Index.

7.10.a.6. CT Gantry - the tube housing assemblies, beam-limiting devices, detectors, and the supporting structures and frames which hold these components.

7.10.a.7. CTN - CT Number.

7.10.a.8. CT Number - the number used to represent the x-ray attenuation associated with each elemental area of the CT image.

Click Here To View Image

associated with each elemental area of the CT image.

where:

FUNC k = A constant, a normal value of one thousand (1,000) when the Houndsfield scale of ctn is used;

mu SUB FUNC x = Linear attenuation coefficient of the material of interest;

mu SUB FUNC w = Linear attenuation coefficient of water.

7.10.a.9. Dose Profile - the dose as a function of position along a line.

7.10.a.10. Elemental Area - he smallest area within a tomogram for which the x-ray attenuation properties of a body are depicted.

7.10.a.11. Multiple Tomogram System - a computed tomography x-ray system which obtains x-ray transmission data simultaneously during a single scan to produce more than one tomogram.

7.10.a.12. Noise - the standard deviation of the fluctuations in CTN expressed as a percentage of the attenuation coefficient of water. Its estimate (S_n) is calculated using the following expression:

Click Here To View Image

where:

FUNC OVERLINE { CS } = Linear attenuation coefficient of the material of interest.

mu SUB FUNC w = Linear attenuation coefficient of water.

FUNC s = Standard deviation of the CTN of picture elements in a specified area of the CT image.

7.10.a.13. Nominal Tomographic Section Thickness - the full width at half-maximum of the sensitivity profile taken at the center of the cross-sectional volume over which x-ray transmission data are collected.

7.10.a.14. Picture Element - an elemental area of a tomogram.

7.10.a.15. Reference Plane - a plane which is displaced from and parallel to the tomographic plane.

7.10.a.16. Scan - the complete process of collecting x-ray transmission data for the production of a tomogram. Data can be collected simultaneously during a single scan for the production of one or more tomograms.

7.10.a.17. Scan Increment - the amount of relative displacement of the patient with respect to the CT x-ray system between successive scans measured along the direction of such displacement.

7.10.a.18. Scan Sequence - a pre-selected set of two or more scans performed consecutively under pre-selected CT conditions of operation.

7.10.a.19. Scan Time - the period of time between the beginning and end of x-ray transmission data accumulation for a single scan.

7.10.a.20. Single Tomogram System - a CT x-ray system which obtains x-ray transmission data during a scan to produce a single tomogram..

7.10.a.21. Tomographic Plane - that geometric plane which is identified as corresponding to the output tomogram.

7.10.a.22. Tomographic Section - the volume of an object whose x-ray attenuation properties are imaged in a tomogram.

7.10.b. Requirements for Equipment.

7.10.b.1. Termination of Exposure.

7.10.b.1.A. Means shall be provided to terminate the x-ray exposure automatically by either de-energizing the x-ray source or shuttering the x-ray beam in the event of equipment failure affecting data collection. Such termination shall occur within an interval that limits the total scan time to no more than one hundred ten (110) percent of its preset value through the use of either a backup timer or devices which monitor equipment function.

7.10.b.1.B. A visible signal shall indicate when the x-ray exposure has been terminated through the means required by Subparagraph 7.10.b.1.A.

7.10.b.1.C. The operator shall be able to terminate the x-ray exposure at any time during a scan, or series of scans under CT x-ray system control, of greater than one-half (_½) second duration.

7.10.b.2. Tomographic Plane Indication and Alignment.

7.10.b.2.A. For any single tomogram system, means shall be provided to permit visual determination of the tomographic plane or a reference plane offset from the tomographic plane.

7.10.b.2.B. For any multiple tomogram system, means shall be provided to permit visual determination of the location of a reference plane. This reference plane can be offset from the location of the tomographic planes.

7.10.b.2.C. If a device using a light source is used to satisfy the requirements of Subparagraphs 7.10.b.2.A. or B., the light source shall provide illumination levels sufficient to permit visual determination of the location of the tomographic plane or reference plane under ambient light conditions of up to five hundred (500) lux.

7.10.b.3. Beam-On and Shutter Status Indicators and Control Switches.

7.10.b.3.A. The CT x-ray control and gantry shall provide visual indication whenever x-rays are produced and, if applicable, whether the shutter is open or closed.

7.10.b.3.B. Each emergency button or switch shall be clearly labeled as to its function.

7.10.b.4. Indication of CT Conditions of Operation. The CT x-ray system shall be designed such that the CT conditions of operation to be used during a scan or a scan sequence shall be indicated prior to the initiation of a scan or a scan sequence. On equipment having all or some of these conditions of operation at fixed values, this requirement may be met by permanent markings. Indication of CT conditions of operation shall be visible from any position from which scan initiation is possible.

7.10.b.5. Extraneous Radiation. When data are not being collected for image production, the radiation adjacent to the tube port shall not exceed that permitted by Subdivision 7.6.c.

7.10.b.6. Maximum Surface CTDI Identification. The angular position where the maximum surface CTDI occurs shall be identified to allow for reproducible positioning of a CT dosimetry phantom.

7.10.b.7. Additional Requirements Applicable to CT X-Ray Systems Containing a Gantry Manufactured After September 3, 1985.

7.10.b.7.A. The total error in the indicated location of the tomographic plane or reference plane shall not exceed five (5) millimeters.

7.10.b.7.B. If the x-ray production period is less than one-half second, the indication of x-ray production shall be accurate for at least one-half (¹/₂) second. Indicators at or near the gantry shall be discernible from any point external to the patient opening where insertion of the human body into the primary beam is possible.

7.10.b.7.C. The deviation of indicated scan increment versus actual increment shall not exceed plus or minus one (1) millimeter with any mass from zero (0) to one hundred (100) kilograms resting on the support device. The patient support device shall be incremented from a typical starting position to the maximum incremented distance or thirty (30) centimeters, whichever is less, and then returned to the starting position. Measurement of actual versus indicated scan increment may be taken anywhere along this travel.

7.10.b.7.D. Premature termination of the x-ray exposure by the operator shall necessitate resetting of the CT conditions of operation prior to the initiation of another scan.

7.10.c. Facility Design Requirements.

7.10.c.1. Aural Communication. Provision shall be made for two-way aural communication between the patient and the operator at the control panel.

7.10.c.2. Viewing Systems.

7.10.c.2.A. Windows, mirrors, closed-circuit television, or an equivalent shall be provided to permit continuous observation of the patient during irradiation and shall be so located that the operator can observe the patient from the control panel.

7.10.c.2.B. When the primary viewing system is by electronic means, an alternate viewing system (which may be electronic) shall be available for use in the event of failure of the primary viewing system.

7.10.d. Surveys, Calibrations, Spot Checks, and Operating Procedures.

7.10.d.1. Surveys.

7.10.d.1.A. All CT x-ray systems installed after July 1, 2000 and those systems not previously surveyed shall have a survey made by, or under the direction of, a qualified expert. In addition, such surveys shall be done after any change in the facility or equipment which might cause a significant increase in radiation hazard.

7.10.d.1.B. The registrant shall obtain a written report of the survey from the qualified expert, and a copy of the report shall be made available to the agency upon request.

7.10.d.2. Radiation Calibrations.

7.10.d.2.A. The calibration of the radiation output of the CT x-ray system shall be performed by, or under the direction of, a qualified expert who is physically present at the facility during such calibration.

7.10.d.2.B. The calibration of a CT x-ray system shall be performed at intervals specified by a qualified expert and after any change or replacement of components which, in the opinion of the qualified expert, could cause a change in the radiation output.

7.10.d.2.C. The calibration of the radiation output of a CT x-ray system shall be performed with a calibrated dosimetry system. The calibration of such system shall be traceable to a national standard. The dosimetry system shall have been calibrated within the preceding two (2) years.

7.10.d.2.D. CT dosimetry phantoms shall be used in determining the radiation output of a CT x-ray system. Such phantoms shall meet the following specifications and conditions of use:

7.10.d.2.D.1. CT dosimetry phantoms shall be right circular cylinders of polymethyl methacrylate of density one and nineteen one-hundredths (1.19) plus or minus one one-hundredth (0.01) grams per cubic centimeter. The phantoms shall be at least fourteen (14) centimeters in length and shall have diameters of thirty two (32.0) centimeters for testing CT x-ray systems designed to image any Section of the body and sixteen (16.0) centimeters for systems designed to image the head or for whole body scanners operated in the head scanning mode;

7.10.d.2.D.2. CT dosimetry phantoms shall provide means for the placement of a dosimeter or dosimeters along the axis of rotation and along a line parallel to the axis of rotation one (1.0) centimeter from the outer surface and within the phantom. Means for the placement of dosimeters or alignment devices at other locations may be provided;

7.10.d.2.D.3. Any effects on the doses measured due to the removal of phantom material to accommodate dosimeters shall be accounted for through appropriate corrections to the reported data or included in the statement of maximum deviation for the values obtained using the phantom;

7.10.d.2.D.4. All dose measurements shall be performed with the CT dosimetry phantom placed on the patient couch or support device without additional attenuation materials present.

7.10.d.2.E. The calibration shall be required for each type of head, body, or whole-body scan performed at the facility.

7.10.d.2.F. Calibration shall meet the following requirements:

7.10.d.2.F.1. The dose profile along the center axis of the CT dosimetry phantom for the minimum, maximum, and midrange values of the nominal tomographic Section thickness used by the registrant shall be measurable. Where less than three (3) nominal tomographic thicknesses can be selected, the dose profile determination shall be performed for each available nominal tomographic Section thickness;

7.10.d.2.F.2. The CTDI6 along the two axes specified in Part 7.10.d.2.D.2. shall be measured. The CT dosimetry phantom shall be oriented so that the measurement point one (1.0) centimeter from the outer surface and within the phantom is in the same angular position within the gantry as the point of maximum surface CTDI identified. The CT conditions of operation shall correspond to typical values used by the registrant;

7.10.d.2.F.3. The spot checks specified in Paragraph 7.10.d.3. shall be made.

7.10.d.2.G. Calibration procedures shall be in writing. Records of calibrations performed shall be maintained for inspection by the agency.

7.10.d.3. Spot Checks.

7.10.d.3.A. The spot-check procedures shall be in writing and shall have been developed by a qualified expert.

7.10.d.3.B. The spot-check procedures shall incorporate the use of a CT dosimetry phantom which has a capability of providing an indication of contrast scale, noise, nominal tomographic Section thickness, the resolution capability of the system for low and high contrast objects, and measuring the mean CTN for water or other reference material.

7.10.d.3.C. All spot checks shall be included in the calibration required by Paragraph 7.10.d.2. and at time intervals and under system conditions specified by a qualified expert.

7.10.d.3.D. Spot checks shall include acquisition of images obtained with the CT dosimetry phantoms using the same processing mode and CT conditions of operation as are used to perform calibrations required by Paragraph 7.11.d.2. The images shall be retained, until a new calibration is performed, in two forms as follows:

7.10.d.3.D.1. Photographic copies of the images obtained from the image display device; and

7.10.d.3.D.2. Images stored in digital form on a storage medium compatible with the CT x-ray system.

7.10.d.3.E. Written records of the spot checks performed shall be maintained for inspection by the agency.

7.10.d.4. Operating Procedures.

7.10.d.4.A. The CT x-ray system shall not be operated except by an individual who has been specifically trained in its operation.

7.10.d.4.B. Information shall be available at the control panel regarding the operation and calibration of the system. Such information shall include the following:

7.10.d.4.B.1. Dates of the latest calibration and spot checks and the location within the facility where the results of those tests may be obtained;

7.10.d.4.B.2. Instructions on the use of the CT dosimetry phantoms including a schedule of spot checks appropriate for the system, allowable variations for the indicated parameters, and the results of at least the most recent spot checks conducted on the system;

7.10.d.4.B.3. The distance in millimeters between the tomographic plane and the reference plane if a reference plane is utilized; and

7.10.d.4.B.4. A current technique chart available at the control panel which specifies for each routine examination the CT conditions of operation and the number of scans per examination.

7.10.d.4.C. If the calibration or spot check of the CT x-ray system identifies that a system operating parameter has exceeded a tolerance established by the qualified expert, use of the CT x-ray system on patients shall be limited to those uses permitted by established written instructions of the qualified expert.

7.11. Mammography.

7.11.a. Equipment Standards. Only x-ray systems meeting the following standards shall be used.

7.11.a.1. System Design. The x-ray system shall be specifically designed for mammography.

7.11.a.2. Image Receptor. The image receptor systems and their individual components shall be specifically designed for or appropriate for mammography. Each screen-film mammography system must have, at a minimum, both an eighteen (18) by twenty four (24) cm and twenty four (24) by thirty (30) cm image receptor and moving grids matched to each image receptor size provided with the system.

7.11.a.3. kVp/Target/Filter. The x-ray system shall have the capability of providing kVp/target/filter combinations compatible with the selected image receptor system.

7.11.a.4. Beam Quality.

7.11.a.4.A. When used with screen-film image receptors, and when the contribution to filtration made by the compression device is included, the useful beam shall have a half-value layer (HVL):

7.11.a.4.A.1. Between the values of: [(measured kVp)/100] and [(measured kVp)/100 + 0.1] millimeters aluminum for molybdenum targets;

7.11.a.4.A.2. At least the value of [(measured kVp)/100] millimeters aluminum for rhodium alloy targets.

7.11.a.4.B. For xeroradiography, the HVL of the useful beam with the compression device in place shall be at least one (1.0) and not greater than one and six-tenths (1.6) mm aluminum, measured at forty nine (49) kVp with a tungsten target tube.

7.11.a.5. Resolution. The combination of focal spot size, source-to-image receptor distance and magnification shall result in a resolution of at least twelve (12) line pairs per millimeter (cycles/mm) measured when a resolution pattern is positioned four and two-tenths (4.2) cm above all breast supports and when the resolution pattern is either perpendicular to or parallel with the chest wall edge of the image receptor support. The measurement shall be made with the kVp in the range of twenty five to thirty (25-30) and the mA shall be the highest available for the focal spot size selected.

7.11.a.6. Compression.

7.11.a.6.A. The x-ray system shall be capable of compressing the breast with a force of at least twenty five (25) pounds and shall be capable of maintaining this compression for at least three (3) minutes. The maximum force shall be no greater than forty (40) pounds.

7.11.a.6.B. The chest wall edge of the compression paddle shall extend beyond the chest wall edge of the image receptor by no more than two (2) percent of the source-to-image receptor distance with the compression paddle placed four and two-tenths (4.2) cm above the breast support device. With the compression paddle in this position, the chest wall edge of the compression paddle shall not be visible in the acquired image.

7.11.a.7. System capabilities. A mammographic x-ray system utilizing screen-film image receptors shall have:

7.11.a.7.A. The capability of using anti-scatter grids which are:

7.11.a.7.A.1. Integral to the x-ray system;

7.11.a.7.A.2. Available for all image receptor sizes used;

7.11.a.7.B. The capability of automatic exposure control, for systems installed after the effective date of this rule; and

7.11.a.7.C. The capability of displaying post-exposure mAs after an exposure made using an automatic exposure control device, for systems installed after the effective date of this rule.

7.11.a.8. Milliampere-Second Read-Out Accuracy. For those mammographic x-ray systems equipped with automatic exposure control and post-exposure mAs read-out, the indicated mAs read-out shall be within ± ten (10) percent of the actual mAs delivered.

7.11.a.9. Transmission. For x-ray systems manufactured after September 5, 1978, the transmission of the primary beam through any image receptor support provided with the system shall be limited such that the exposure five (5) centimeters from any accessible surface beyond the plane of the image receptor supporting device does not exceed twenty five and eight-tenths (25.8) nC/kg (one-tenth [0.1] milliroentgen) for each activation of the tube. Exposure shall be measured with the system operated at the minimum SID for which it is designed. Compliance shall be determined at the maximum rated peak tube potential for the system and at the maximum rated product of tube current and exposure time (mAs) for that peak tube potential. Compliance shall be determined by measurements averaged over an area of one hundred (100) square centimeters with no linear dimension greater than twenty (20) centimeters.

7.11.a.10. Collimation.

7.11.a10.A. The mammographic system shall be provided with means to limit the useful beam such that the x-ray field at the plane of the image receptor does not extend beyond any edge of the image receptor at any designated SID except the edge of the image receptor designed to be adjacent to the chest wall where the x-ray field may not extend beyond this edge by more than two (2) percent of the SID.

7.11.a.10.B. Means for visually defining the perimeter of the x-ray field shall be provided. The total misalignment of the edges of the visually defined field with the respective edges of the x-ray field along either the length or width of the visually defined field shall not exceed two (2) percent of the distance from the source to the center of the visually defined field when the surface upon which it appears is perpendicular to the axis of the x-ray beam.

7.11.a.11. Accuracy of kVp. Deviation of actual kVp from the indicated kVp shall not exceed the limits specified by the manufacturer of the x-ray system, or, the actual kVp shall be within ± two (2) kVp of the indicated kVp, whichever limit is more restrictive.

7.11.a.12. Automatic Exposure Control Performance. In addition to Subdivision 7.8.d., mammographic systems in the AEC mode shall be able to maintain constant film density to within an optical density of ± three-tenths (0.3) of the average optical density over the kVp range used clinically, using phantoms of BR-12 or other breast equivalent material thicknesses of two (2) centimeters to six (6) centimeters. If the facility has established a technique chart that utilizes varying technical factors for different breast thicknesses, those adjustments in technique may be used when performing this test.

7.11.a.13. Radiation Output Minimum. At twenty eight (28) kVp, with a focal spot meeting the requirements of Paragraph 7.11.a.5., the mammographic system shall be capable of sustaining a minimum output rate of one hundred thirty (130) :C/kg/sec (five hundred [500] mR/sec) for at least three (3) seconds. This output shall be measured at a point four and two-tenths (4.2) centimeters from the surface of the breast support device when the SID is at its maximum and the effect of compression paddle attenuation is included.

7.11.a.14. Screen-film Contact. Cassettes shall not be used for mammography if poor contact of two or more large areas ( one [1] cm in diameter) or a Section longer than one [1] cm and two (2) mm in width along the chest wall edge can be seen in a forty (40) mesh test.

7.11.a.15. Image quality. The mammographic x-ray imaging system shall be capable of providing an image of a seventy five one-hundredths (0.75) mm fiber, thirty two one-hundredths (0.32) mm speck group, and a seventy five one-hundredths (0.75) mm mass from the conference of Radiation Control Program directors next '92 phantom (or equivalent) on the standard mammographic image receptor system in use at a facility. Mammograms shall not be taken on patients if this minimum is not met. Any fibers, speck groups and masses larger than those specified shall also be imaged.

7.11.a.16. Dose. The mean glandular dose for one craniocaudal view, measured with the phantom referenced in Paragraph 7.11.a.15., based on exposure measured at the breast entrance location, and using dose conversion factors specified by the health care financing administration in their medicare mammography survey protocols, shall not exceed the following values:

7.11.a.16.A. One and five one-hundredths (1.5) mGy (one hundred fifty [150] millirads) for non-grid screen film systems;

7.11.a.16.B. Two and five one-hundredths (2.5) mGy (two hundred fifty [250] millirads) for screen-film systems with grid;

7.11.a.16.C. Four (4) mGy (four hundred [400] millirads) for xerography systems.

7.11.a.17. Technique Settings. The technique settings used for Paragraphs 7.11.a.15. and 16. shall be those used by the facility for its clinical images of a fifty (50) percent adipose, fifty (50) percent glandular, four and two one-hundredths (4.2) cm compressed breast.

7.11.b. Quality Assurance.

7.11.b.1. Quality Assurance Program Required. The registrant shall have a written, on-going equipment quality assurance program specific to mammographic imaging, covering all components of the diagnostic x-ray imaging system, to ensure consistently high-quality images with minimum patient exposure. Responsibilities under this requirement include providing qualified individuals who are to:

7.11.b.1.A. Conduct equipment performance monitoring functions;

7.11.b.1.B. Analyze the monitoring results to determine if there are problems requiring correction;

7.11.b.1.C. Carry out or arrange for the necessary corrective actions when results of quality control tests including those specified in Paragraph 7.11.b.3. indicate the need; and

7.11.b.1.D. Maintain records for a minimum of two years documenting that actions required under Subparagraph 7.11.b.1.A. - C. have been completed.

7.11.b.2. Quality Assurance Program Review. At intervals not to exceed twelve months, the registrant shall:

7.11.b.2.A. Have the annual quality control tests specified in 7.11.b.3. performed by a qualified individual (table 64-23 P) and obtain the results of those tests, incorporating them into the records specified in Subparagraph 7.11.b.1.D.; and

7.11.b.2.B. Conduct a review of the effectiveness of the quality assurance program required in Paragraph 7.11.b.1. and maintain a written report of such review. Records of annual reviews shall be maintained for a minimum of two (2) years and shall be available for agency review.

7.11.b.3. Equipment Quality Control Tests. The registrant shall ensure that the following quality control tests are performed when applicable equipment or components are initially installed, or replaced or serviced (if such servicing affects test results), and performed thereafter at least as often as the frequency specified. If such tests indicate the need for corrective action, based on limits defined here, or in Subdivision 7.11.a., patient mammography may not be performed until correction is accomplished.

7.11.b.3.A. Processor performance by sensitometric - daily, or day of use, prior to the first patient exposure. For any mammography registrant using film processors at multiple locations, such as a mobile service, each processor shall be subject to this requirement. Corrective action shall be taken when:

7.11.b.3.A.1. Deviations of ± fifteen one-hundredths (0.15) or more in optical density from established operating levels occur for readings of mid-density (MD) and density difference (DD) on the sensitometric control charts;

7.11.b.3.A.2. Base plus fog (B+F) exceeds the established operating level by more than three one-hundredths (0.03) in optical density.

7.11.b.3.B. Resolution - upon tube installation or replacement and every twelve (12) months.

7.11.b.3.C. Focal spot size - upon tube installation or tube replacement only.

7.11.b.3.D. Half-value layer - twelve (12) months.

7.11.b.3.E. kVp accuracy and reproducibility - twelve (12) months.

7.11.b.3.F. Output reproducibility, mA linearity, and mR/mAs - twelve (12) months.

7.11.b.3.G. Automatic exposure control reproducibility and performance (response to kVp and phantom thickness variations) - twelve (12) months.

7.11.b.3.H. Screen-film contact and screen artifact detection - six (6) months.

7.11.b.3.I. Compression device performance (releases, level of force, etc) - six (6) months.

7.11.b.3.J. Collimator alignment - twelve (12) months.

7.11.b.3.K. Primary or secondary barrier transmission - upon initial x-ray system installation and significant modification of the system or the facility.

7.11.b.3.L. Image quality (using a test "phantom," which simulates the composition of the breast and includes simulations of breast structures) - monthly for stationary systems, on each day of use for mobile systems, and upon significant service or modification of any mammographic system.

7.11.b.3.M. Densitometer accuracy check - every six (6) months.

7.11.b.3.N. If xeroradiography is used, the quality assurance procedures and frequencies recommended by the manufacturer shall be followed.

7.11.b.4. Additional Quality Control Requirements. The registrant shall perform the following observations and procedures according to the frequency noted and record the results. Corrections of problems noted shall be made and recorded. Records shall be maintained over the most recent two (2) year period.

7.11.b.4.A. Retake Analysis - Three (3) months, or every two hundred fifty (250) patients, whichever comes first.

7.11.b.4.B. Viewbox uniformity - Six (6) months.

7.11.b.4.C. Darkroom integrity (safelight condition, light leaks, etc.) - Six (6) months.

7.11.b.4.D. Screen cleaning - weekly.

7.11.c. Additional Facility Requirements.

7.11.c.1. Masks. Masks shall be provided on the viewboxes to block extraneous light from the viewer's eye when the illuminated surface of the viewbox is larger than the exposed area of the film.

7.11.c.2. Film Processing.

7.11.c.2.A. Film processors utilized for mammography shall be adjusted to and operated at the specifications recommended by the mammographic film manufacturer, or at other settings such that the sensitometric performance is at least equivalent.

7.11.c.2.B. Clinical films and phantom image quality films shall be processed within ten (10) hours of exposure.

7.11.c.3. Instruments and Devices. An image quality phantom, sensitometer, and a calibrated densitometer shall be available to each facility in order to comply with the quality control test frequencies specified in Paragraph 7.11.b.3.

7.11.c.4. Operator Qualifications. The operator of the x-ray machine shall be certified by the american registry of radiologic technologists or an equivalent state licensing body and shall have had specialized training in mammography.

7.11.c.5. Physician Qualifications. The physician interpreting the mammograms shall be certified by the American Board of Radiology, the American Osteopathic Board of Radiology, or board eligible, or equivalent, and shall have had specialized training in mammography and image interpretation.

7.11.c.6. Physicist Qualifications. The person performing evaluation of mammographic system performance in accordance with this rule shall be certified by the American Board of Radiology, the American Board of Medical Physics, or with academic and experience required for board certification, or equivalent, or recognized as competent by an appropriate state agency.

7.11.c.7. Image Retention. Clinical images shall be retained for a minimum of five (5) years.

7.11.c.8. Retake Rate. Corrective action shall be taken if the retake rate exceeds five (5) percent. The retake rate shall be calculated as [repeated + rejected films]/ total number of clinical films.

7.11.c.9. Darkroom Fog. Darkroom fog levels shall not exceed five one-hundredths (0.05) in optical density when sensitized mammographic film of the type used in the facility is exposed to darkroom conditions with safelight on for two (2) minutes. Film shall be sensitized by exposing it to sufficient light from an appropriate intensifying screen or sensitometer so that after processing an optical density of one and two-tenths to one and five-tenths (1.2 - 1.5) is achieved.

7.12. Therapeutic Radiation Machines

7.12.a. Purpose and Scope.

7.12.a.1. This Section establishes requirements, for which the registrant is responsible, for use of therapeutic radiation machines. The provisions of this Section are in addition to, and not in substitution for, other applicable provisions of this rule.

7.12.a.2. The use of therapeutic radiation machines shall be by, or under the supervision of, a licensed practitioner of the healing arts who meets the training and experience criteria established by Subdivision 12.3.c.

7.12.b. Definitions. As used in this Section, the following definitions apply:

7.12.b.1. Absorbed Dose (D) - the mean energy imparted by ionizing radiation to matter. Absorbed dose is determined as the quotient of dE by dM, where dE is the mean energy imparted by ionizing radiation to matter of mass dM.. The SI unit of absorbed dose is joule per kilogram and the special name of the unit of absorbed dose is the Gray (Gy). The previously used special unit of absorbed dose (rad) is being replaced by the gray.

7.12.b.2. Absorbed Dose Rate - absorbed dose per unit time, for machines with timers, or dose monitor unit per unit time for linear accelerators.

7.12.b.3. Accessible Surface - surface of equipment or of an equipment part that can be easily or accidentally touched by persons without the use of a tool.

7.12.b.4. Added Filtration - any filtration which is in addition to the inherent filtration.

7.12.b.5. Air Kerma (K) - the kinetic energy released in air by ionizing radiation. Kerma is determined as the quotient of dE by dM, where dE is the sum of the initial kinetic energies of all the charged ionizing particles liberated by uncharged ionizing particles in air of mass dM.. The SI unit of air kerma is joule per kilogram and the special name for the unit of kerma is the gray (Gy).

7.12.b.6. Barrier - a barrier of radiation absorbing materials used to reduce radiation exposure.

7.12.b.7. Beam Axis - the axis of rotation of the beam limiting device.

7.12.b.8. Beam-limiting Device - a field defining collimator, integral to the therapeutic radiation machine, which provides a means to restrict the dimensions of the useful beam.

7.12.b.9. Beam Monitoring System - a system designed and installed in the radiation head to detect and measure the radiation present in the useful beam.

7.12.b.10. Beam Scattering Foil - a thin piece of material (usually metallic) placed in the beam to scatter a beam of electrons in order to provide a more uniform electron distribution in the useful beam.

7.12.b.11. Bent Beam Linear Accelerator - a linear accelerator geometry in which the accelerated electron beam must change direction by passing through a bending magnet.

7.12.b.12. Changeable Filters - any filter, exclusive of inherent filtration, which can be removed from the useful beam through any electronic, mechanical, or physical process.

7.12.b.13. Contact Therapy System - a therapeutic radiation machine with a short target to skin distance (TSD), usually less than five (5) centimeters.

7.12.b.14. Detector - a device which, in the presence of radiation provides, by either direct or indirect means, a signal or other indication suitable for use in measuring one or more quantities of incident radiation.

7.12.b.15. Dose Monitor Unit (DMU) - a unit response from the beam monitoring system from which the absorbed dose can be calculated.

7.12.b.16. External Beam Radiation Therapy - therapeutic irradiation in which the source of radiation is at a distance from the body.

7.12.b.17. Field-flattening Filter - a filter used to homogenize the absorbed dose rate over the radiation field.

7.12.b.18. Filter - material placed in the useful beam to change beam quality in therapeutic radiation machines subject to Subdivision 7.12.f.

7.12.b.19. Gantry - that part of a radiation therapy system supporting and allowing movements of the radiation head about a center of rotation.

7.12.b.20. Gray (Gy) - the SI unit of absorbed dose, kerma, and specific energy imparted equal to 1 joule per kilogram. The previous unit of absorbed dose (rad) is being replaced by the Gray. (one [1] Gy=one hundred [100] rad).

7.12.b.21. Half-value Layer (HVL) - the thickness of a specified material which attenuates x-radiation or gamma radiation to an extent such that the air kerma rate, exposure rate or absorbed dose rate is reduced to one-half (_½) of the value measured without the material at the same point.

7.12.b.22. Interlock - a device preventing the start or continued operation of equipment unless certain predetermined conditions prevail.

7.12.b.23. Interruption of Irradiation - the stopping of irradiation with the possibility of continuing irradiation without resetting of operating conditions at the control panel.

7.12.b.24. Irradiation - the exposure of a living being or matter to ionizing radiation.

7.12.b.25. Isocenter - the center of the sphere through which the useful beam axis passes while the gantry moves through its full range of motions.

7.12.b.26. Kilovolt (kV) [kilo electron volt (keV)] - the energy equal to that acquired by a particle with one electron charge in passing through a potential difference of one thousand volts in a vacuum. [Note: current convention is to use kV for photons and keV for electrons.]

7.12.b.27. Lead Equivalent - the thickness of the material in question affording the same attenuation, under specified conditions, as lead.

7.12.b.28. Leakage Radiation - radiation emanating from the radiation therapy system except for the useful beam.

7.12.b.29. Light Field - the area illuminated by light, simulating the radiation field.

7.12.b.30. mA - milliampere.

7.12.b.31. Megavolt (MV) [mega electron volt (MeV)] - the energy equal to that acquired by a particle with one electron charge in passing through a potential difference of one million volts in a vacuum. [Note: current convention is to use MV for photons and MeV for electrons.]

7.12.b.32. Monitor Unit (MU) -a unit response from the beam monitoring system from which the absorbed dose can be calculated.

7.12.b.31. Moving Beam Radiation Therapy - radiation therapy with any planned displacement of radiation field or patient relative to each other, or with any planned change of absorbed dose distribution. It includes arc, skip, conformal, intensity modulation and rotational therapy.

7.12.b.32. Nominal Treatment Distance:

7.12.b.32.A. For electron irradiation, the distance from the scattering foil, virtual source, or exit window of the electron beam to the entrance surface of the irradiated object along the central axis of the useful beam.

7.12.b.32.B. For x-ray irradiation, the virtual source or target to isocenter distance along the central axis of the useful beam. For non-isocentric equipment, this distance shall be that specified by the manufacturer.

7.12.b.33. Patient - an individual subjected to machine produced external beam radiation for the purposes of medical therapy.

7.12.b.34. Peak Tube Potential - the maximum value of the potential difference across the x-ray tube during an exposure.

7.12.b.35. Periodic Quality Assurance Check - a procedure which is performed to ensure that a previous calibration continues to be valid.

7.12.b.36. Phantom - an object behaving in essentially the same manner as tissue, with respect to absorption or scattering of the ionizing radiation in question.

7.12.b.37. Practical Range of Electrons - corresponds to classical electron range where the only remaining contribution to dose is from Bremsstrahlung X-rays. A further explanation may be found in "Clinical Electron Beam Dosimetry: Report of AAPM Radiation Therapy Committee Task Group 25" [Medical Physics 18(1): 73-109, Jan/Feb. 1991] and ICRU Report 35, "Radiation Dosimetry: Electron Beams with Energies Between 1 and 50 MeV", International Commission on Radiation Units and Measurements, September 15, 1984.

7.12.b.38. Primary Dose Monitoring System - a system which will monitor the useful beam during irradiation and which will terminate irradiation when a pre-selected number of dose monitor units have been delivered.

7.12.b.39. Primary Protective Barrier - the material, excluding filters, placed in the useful beam.

7.12.b.40. Protective Barrier - a barrier of radiation absorbing materials used to reduce radiation exposure.

7.12.b.41. Radiation Detector - a device which, in the presence of radiation provides, by either direct or indirect means, a signal or other indication suitable for use in measuring one or more quantities of incident radiation.

7.12.b.42. Radiation Field - the material which attenuates stray radiation.

7.12.b.43. Radiation Head - the structure from which the useful beam emerges.

7.12.b.44. Radiation Therapy Physicist - an individual qualified in accordance with Paragraph 7.12.c.4.

7.12.b.45. Redundant Beam Monitoring System - a combination of two dose monitoring systems in which each system is designed to terminate irradiation in accordance with a pre-selected number of dose monitor units.

7.12.b.46. Scattered Radiation - ionizing radiation emitted by interaction of ionizing radiation with matter, the interaction being accompanied by a change in direction of the radiation. Scattered primary radiation means that scattered radiation which has been deviated in direction only by materials irradiated by the useful beam.

7.12.b.47. Secondary Dose Monitoring System - a system which will terminate irradiation in the event of failure of the primary dose monitoring system.

7.12.b.48. Secondary Protective Barrier - the material which attenuates stray radiation.

7.12.b.49. Shadow Tray - a device attached to the radiation head to support auxiliary beam blocking material.

7.12.b.50. Shutter - a device attached to the tube housing assembly which can totally intercept the useful beam and which has a lead equivalency not less than that of the tube housing assembly.

7.12.b.51. Sievert (Sv) - the SI unit of dose equivalent. The unit of dose equivalent is the joule per kilogram. The previous unit of dose equivalent (Rem) is being replaced by the Sievert. (One [1] Sv=one hundred [100] Rem).

7.12.b.52. Simulator (Radiation Therapy Simulation System) - any x-ray system intended for localizing the volume to be exposed during radiation therapy and reproducing the position and size of the therapeutic irradiation field.

7.12.b.53. Source - the region or material from which the radiation emanates.

7.12.b.54. Source-skin Distance (SSD) - the distance measured along the beam axis from the center of the front surface of the x-ray target or electron virtual source to the surface of the irradiated object or patient.

7.12.b.55. Stationary beam radiation therapy - radiation therapy without displacement of one or more mechanical axes relative to the patient during irradiation.

7.12.b.56. Stray Radiation - the sum of leakage and scattered radiation.

7.12.b.57. Target - that part of an x-ray tube or accelerator onto which a beam of accelerated particles is directed to produce ionizing radiation or other particles.

7.12.b.58. Target-skin Distance (TSD) - the distance measured along the beam axis from the center of the front surface of the x-ray target or electron virtual source to the surface of the irradiated object or patient.

7.12.b.59. Tenth-value Layer (TVL) - s the thickness of a specified material which attenuates x-radiation or gamma radiation to an extent such that the air kerma rate, exposure rate, or absorbed dose rate is reduced to one-tenth (0.1) of the value measured without the material at the same point.

7.12.b.60. Termination of Irradiation - the stopping of irradiation in a fashion which will not permit continuance of irradiation without the resetting of operating conditions at the control panel.

7.12.b.61. Therapeutic Radiation Machine - x-ray or electron-producing equipment designed and used for external beam radiation therapy.

7.12.b.62. Tube - an x-ray tube, unless otherwise specified.

7.12.b.63. Tube Housing Assembly - the tube housing with tube installed. It includes high-voltage or filament transformers and other appropriate elements when such are contained within the tube housing.

7.12.b.64. Useful Beam - the radiation emanating from the tube housing port or the radiation head and passing through the aperture of the beam limiting device when the exposure controls are in a mode to cause the therapeutic radiation machine to produce radiation.

7.12.b.65. Virtual Source - a point from which radiation appears to originate.

7.12.b.66. Wedge Filter - a filter which effects continuous change in transmission over all or a part of the useful beam.

7.12.b.67. X-ray Tube - any electron tube which is designed to be used primarily for the production of x-rays.

7.12.c. General Administrative Requirements for Facilities Using Therapeutic Radiation Machines.

7.12.c.1. The registrant shall be responsible for directing the operation of the therapeutic radiation machines that have been registered with the agency. The registrant or the registrant's agent shall ensure that the requirements of Subsection 7.12. are met in the operation of the therapeutic radiation machines.

7.12.c.2. A therapeutic radiation machine that does not meet the provisions of this rule shall not be used for irradiation of patients.

7.12.c.3. The registrant for any therapeutic radiation machine subject to Subdivisions 7.12.f. or 7.12.g. shall require the radiation therapy physicist to:

7.12.c.3.A. Be registered with the agency, under the provisions of Section 2. of this rule, as a provider of radiation services in the area of calibration and compliance surveys of external beam radiation therapy units; and

7.12.c.3.B. Be certified by the American Board of Radiology in:

7.12.c.3.B.1. Therapeutic Radiological Physics; or

7.12.c.3.B.2. Roentgen-ray and Gamma-ray Physics; or

7.12.c.3.B.3. X-ray and Radium Physics; or

7.12.c.3.B.4. Radiological Physics; or

7.12.c.3.C. Be certified by the American Board of Medical Physics in Radiation Oncology Physics; or

7.12.c.3.D. Hold a master's or doctor's degree in physics, biophysics, radiological physics, or health physics, and have completed 1 year of full time training in therapeutic radiological physics and also 1 year of full time work experience under the supervision of a radiation therapy physicist at a medical institution. To meet this requirement, the individual shall have performed the tasks listed in 7.12.d.1., 7.12.f.16. or 7.12.g.20., and 7.12.f.17. or 7.12.g.21. under the supervision of a radiation therapy physicist during the year of work experience.

7.12.c.3.E. Notwithstanding the provisions of 7.12.c.3.C., certification pursuant 7.12.c.3.B. and 7.12.c.3.C. shall be required on or before December 31, 1999, for all persons currently qualifying as a radiation therapy physicist pursuant to 7.12.c.3.D.

7.12.c.4. Written safety procedures and rules shall be developed by a radiation therapy physicist and shall be available in the control area of a therapeutic radiation machine, including any restrictions required for the safe operation of the particular therapeutic radiation machine. The operator shall be able to demonstrate familiarity with this rule.

7.12.c.5. Individuals shall not be exposed to the useful beam except for medical therapy purposes and unless such exposure has been ordered in writing by a licensed practitioner of the healing arts who is specifically identified on the registration. This provision specifically prohibits deliberate exposure of an individual for training, demonstration or other non-healing-arts purposes.

7.12.c.6. Visiting Authorized User.

7.12.c.6.A. Notwithstanding the provisions of 7.12.c.5., a registrant may permit any physician to act as a visiting authorized user under the term of the registrant's registration for up to sixty (60) days per calendar year under the following conditions:

7.12.c.6.A.1. The visiting authorized user has the prior written permission of the registrant's management and, if the use occurs on behalf of an institution, the institution's radiation safety committee; and

7.12.c.6.A.2. The visiting authorized user meets the requirements established for authorized users in 7.12.c.3.B.; and

7.12.c.6.a.3. The registrant maintains copies of all records specified by 7.12.c.6. for five (5) years from the date of the last visit.

7.12.c.6.B. All individuals associated with the operation of a therapeutic radiation machine shall be instructed in and shall comply with the provisions of the registrant's quality management program. In addition to the requirements of Subsection 7.12, these individuals are also subject to the requirements of Subsection 6.5., Subsection 6.9. and Subsection 6.17. of this rule.

7.12.c.7. Information and Maintenance Record and Associated Information. The registrant shall maintain the following information in a separate file or package for each therapeutic radiation machine, for inspection by the agency:

7.12.c.7.A. Report of acceptance testing;

7.12.c.7.B. Records of all surveys, calibrations, and periodic quality assurance checks of the therapeutic radiation machine required by Subsection 7.12., as well as the names of persons who performed such activities;

7.12.c.7.C. Records of maintenance and modifications performed on the therapeutic radiation machine after July 1, 2001, as well as the names of persons who performed such services;

7.12.c.7.D. Signature of person authorizing the return of therapeutic radiation machine to clinical use after service, repair, or upgrade.

7.12.c.8. Records Retention. All records required by Subsection 7.12. shall be retained until disposal is authorized by the agency unless another retention period is specifically authorized in Subsection 7.12. All required records shall be retained in an active file from at least the time of generation until the next Agency inspection. Any required record generated prior to the last agency inspection may be microfilmed or otherwise archived as long as a complete copy of said record can be retrieved until such time as the agency authorizes final disposal.

7.12.d. General Technical Requirements for Facilities Using Therapeutic Radiation Machines.

7.12.d.1. Protection Surveys.

7.12.d.1.A. The registrant shall ensure that radiation protection surveys of all new facilities, and existing facilities not previously surveyed are performed with an operable radiation measurement survey instrument calibrated in accordance with 7.12.h. The radiation protection survey shall be performed by, or under the direction of, a radiation therapy physicist or a qualified expert and shall verify that, with the therapeutic radiation machine in a "BEAM-ON" condition, with the largest clinically available treatment field and with a scattering phantom in the useful beam of radiation:

7.12.d.1.A.1. Radiation levels in restricted areas are not likely to cause personnel exposures in excess of the limits specified in Subdivision 6.5.a. of this rule.; and

7.12.d.1.A.2. Radiation levels in unrestricted areas do not exceed the limits specified in Subdivisions 6.13.a. and 6.13.b. of this rule.

7.12.d.1.B. In addition to the requirements of Subparagraph 7.12.d.1.A., a radiation protection survey shall also be performed prior to any subsequent medical use and:

7.12.d.1.B.1. After making any change in the treatment room shielding;

7.12.d.1.B.2. After making any change in the location of the therapeutic radiation machine within the treatment room;

7.12.d.1.B.3. After relocating the therapeutic radiation machine; or

7.12.d.1.B.4. Before using the therapeutic radiation machine in a manner that could result in increased radiation levels in areas outside the external beam radiation therapy treatment room.

7.12.d.1.C. The survey record shall indicate all instances where the facility, in the opinion of the radiation therapy physicist or a qualified expert, is in violation of applicable rules. The survey record shall also include: the date of the measurements; the reason the survey is required; the manufacturer's name; model number and serial number of the therapeutic radiation machine; the instruments used to measure radiation levels; a plan of the areas surrounding the treatment room that were surveyed; the measured dose rate at several points in each area expressed in microsieverts or millirems per hour; the calculated maximum level of radiation over a period of one (1) week for each restricted and unrestricted area; and the signature of the individual responsible for conducting the survey;

7.12.d.1.D. If the results of the surveys required by 7.12.d.1.A. or 7.12.d.1.B. indicate any radiation levels in excess of the respective limit specified in Subparagraph 7.12.d.1.A., the registrant shall lock the control in the "OFF" position and not use the unit:

7.12.d.1.D.1. Except as may be necessary to repair, replace, or test the therapeutic radiation machine, the therapeutic radiation machine shielding, or the treatment room shielding; or

7.12.d.1.D.2. Until the registrant has received a specific exemption from the agency.

7.12.d.2. Modification of radiation therapy unit or room before beginning a treatment program. If the survey required by Paragraph 7.12.d.1. indicates that an individual in an unrestricted area may be exposed to levels of radiation greater than those permitted by Subdivisions 6.13.a. and 6.13.b. of this rule, before beginning the treatment program the registrant shall:

7.12.d.2.A. Either equip the unit with beam direction interlocks or add additional radiation shielding to ensure compliance with Subdivisions 6.13.a. and 6.13.b. of this rule;

7.12.d.2.B. Perform the survey required by Paragraph 7.12.d.1. again; and

7.12.d.2.C. Include in the report required by Paragraph 7.12.d.4. the results of the initial survey, a description of the modification made to comply with Subparagraph 7.12.d.2.A., and the results of the second survey; or

7.12.d.2.D. Request and receive a registration amendment under Subdivision 6.13.c. of this rule that authorizes radiation levels in unrestricted areas greater than those permitted by Subdivision 6.13.a and 6.13.b. of this rule.

7.12.d.3. Dosimetry Equipment.

7.12.d.3.A. The registrant shall have a calibrated dosimetry system available for use. The system shall have been calibrated by the National Institute for Standards and Technology (NIST) or by an American Association of Physicists in Medicine (AAPM) accredited dosimetry calibration laboratory (ADCL). The calibration shall have been performed within the previous twenty four (24) months and after any servicing that may have affected system calibration. An independent survey shall be conducted by a qualified expert or radiation therapy physicist other that the person performing the original survey prior to the equipment being used except as described in Subparagraph 7.12.d.1.D.

7.12.d.3.A.1. For beams with energies greater than one (1) MV (one [1] MeV), the dosimetry system shall have been calibrated for Cobalt-60;

7.12.d.3.A.2. For beams with energies equal to or less than one (1) MV (one [1] MeV), the dosimetry system shall have been calibrated at an energy (energy range) appropriate for the radiation being measured;

7.12.d.3.B. The registrant shall have available for use a dosimetry system for quality assurance check measurements. To meet this requirement, the system may be compared with a system that has been calibrated in accordance with Subparagraph 7.12.d.3.A. This comparison shall have been performed within the previous twelve (12) months and after each servicing that may have affected system calibration. The quality assurance check system may be the same system used to meet the requirement in 7.12.d.3.1.;

7.12.d.3.C. The registrant shall maintain a record of each dosimetry system calibration, intercomparison, and comparison for the duration of the registration. For each calibration, intercomparison, or comparison, the record shall include: the date; the model numbers and serial numbers of the instruments that were calibrated, inter-compared, or compared as required by 7.12.d.3.A. and 7.12.d.3.B.; the correction factors that were determined; the names of the individuals who performed the calibration, intercomparison, or comparison; and evidence that the intercomparison was performed by, or under the direct supervision and in the physical presence of, a radiation therapy physicist.

7.12.d.4. Reports of external beam radiation therapy surveys and measurements. The registrant for any therapeutic radiation machine subject to Subdivisions 7.12.f. or 7.12.g. shall furnish a copy of the records required in Paragraphs 7.12.d.1. and 7.12.d.2. to the agency within thirty (30) days following completion of the action that initiated the record requirement.

7.12.e. Quality Management Program. The facility shall implement a quality management program. The facility may use the quality management programs found in either Table 64-23 V or Table 64-23 W.

7.12.f. Therapeutic Radiation Machines of Less Than Five Hundred (500) kV.

7.12.f.1. Leakage Radiation. When the x-ray tube is operated at its maximum rated tube current for the maximum kV, the leakage air kerma rate shall not exceed the value specified at the distance specified for that classification of therapeutic radiation machine:

7.12.f.1.A. Five to Fifty (5 to 50) kV Systems. The leakage air kerma rate measured at any position 5 centimeters from the tube housing assembly shall not exceed one (1) mGy (one hundred [100] mRad) in any one hour.

7.12.f.1.B. Greater than fifty (50) and less than five hundred (500) kV Systems. The leakage air kerma rate measured at a distance of one (1) meter from the target in any direction shall not exceed one (1) cGy (one [1] Rad) in any one (1) hour. This air kerma rate measurement may be averaged over areas no larger than one hundred (100) square centimeters. In addition, the air kerma rate at a distance of five (5) centimeters from the surface of the tube housing assembly shall not exceed thirty (30) cGy (thirty [30] rad) per hour.

7.12.f.1.C. For each therapeutic radiation machine, the registrant shall determine, or obtain from the manufacturer, the leakage radiation existing at the positions specified in Subparagraph 7.12.f.1.A. and 7.12.f.1.B. for the specified operating conditions. Records on leakage radiation measurements shall be maintained at the installation for inspection by the agency.

7.12.f.2. Permanent beam limiting devices. Permanent diaphragms or cones used for limiting the useful beam shall provide at least the same degree of attenuation as required for the tube housing assembly.

7.12.f.3. Adjustable or Removable Beam Limiting Devices.

7.12.f.3.A. All adjustable or removable beam limiting devices, diaphragms, cones or blocks shall not transmit more than five (5) percent of the useful beam for the most penetrating beam used;

7.12.f.3.B. When adjustable beam limiting devices are used, the position and shape of the radiation field shall be indicated by a light beam.

7.12.f.4. Filter System. The filter system shall be so designed that:

7.12.f.4.A. Filters can not be accidentally displaced at any possible tube orientation;

7.12.f.4.B. For equipment installed after July 1, 2001, an interlock system prevents irradiation if the proper filter is not in place;

7.12.f.4.C. The air kerma rate escaping from the filter slot shall not exceed one (1) cGy (1 Rad) per hour at 1 meter under any operating conditions; and

7.12.f.4.D. Each filter shall be marked as to its material of construction and its thickness.

7.12.f.5. Tube Immobilization.

7.12.f.5.A. The x-ray tube shall be so mounted that it can not accidentally turn or slide with respect to the housing aperture; and

7.12.f.5.B. The tube housing assembly shall be capable of being immobilized for stationary portal treatments.

7.12.f.6. Source Marking. The tube housing assembly shall be so marked that it is possible to determine the location of the source to within five (5) millimeters, and such marking shall be readily accessible for use during calibration procedures.

7.12.f.7. Beam Block. Contact therapy tube housing assemblies shall have a removable shield of material, equivalent in attenuation to five-tenths (0.5) millimeters of lead at one hundred (100) kV, which can be positioned over the entire useful beam exit port during periods when the beam is not in use.

7.12.f.8. Timer. A suitable irradiation control device shall be provided to terminate the irradiation after a pre-set time interval.

7.12.f.8.A. A timer with a display shall be provided at the treatment control panel. The timer shall have a pre-set time selector and an elapsed time or time remaining indicator;

7.12.f.8.B. The timer shall be a cumulative timer that activates with an indication of "BEAM-ON" and retains its reading after irradiation is interrupted or terminated. After irradiation is terminated and before irradiation can be reinitiated, it shall be necessary to reset the elapsed time indicator;

7.12.f.8.C. The timer shall terminate irradiation when a pre-selected time has elapsed, if any dose monitoring system present has not previously terminated irradiation;

7.12.f.8.D. The timer shall permit accurate pre-setting and determination of exposure times as short as one (1) second;

7.12.f.8.E. The timer shall not permit an exposure if set at zero;

7.12.f.8.F. The timer shall not activate until the shutter is opened when irradiation is controlled by a shutter mechanism unless calibration includes a timer error correction to compensate for mechanical lag; and

7.12.f.8.G. Timer shall be accurate to within one (1) percent of the selected value or one (1) second, whichever is greater.

7.12.f.9. Control Panel Functions. The control panel, in addition to the displays required by other provisions in Subdivision 7.12.f., shall have:

7.12.f.9.A. An indication of whether electrical power is available at the control panel and if activation of the x-ray tube is possible;

7.12.f.9.B. An indication of whether x-rays are being produced;

7.12.f.9.C. A means for indicating x-ray tube potential and current;

7.12.f.9.D. The means for terminating an exposure at any time;

7.12.f.9.E. A locking device which will prevent unauthorized use of the therapeutic radiation machine; and

7.12.f.9.F. For therapeutic radiation machines manufactured after July 1, 2001, a positive display of specific filter or filters in the beam.

7.12.f.10. Multiple Tubes. When a control panel may energize more than one (1) x-ray tube:

7.12.f.10.A. It shall be possible to activate only one x-ray tube at any time;

7.12.f.10.B. There shall be an indication at the control panel identifying which x-ray tube is activated; and

7.12.f.10.C. There shall be an indication at the tube housing assembly when that tube is energized.

7.12.f.11. Target-to-Skin Distance (TSD). There shall be a means of determining the central axis TSD to within one (1) centimeter and of reproducing this measurement to within two (2) millimeters thereafter.

7.12.f.12. Shutters. Unless it is possible to bring the x-ray output to the prescribed exposure parameters within five (5) seconds after the x-ray "ON" switch is energized, the beam shall be attenuated by a shutter having a lead equivalency not less than that of the tube housing assembly. In addition, after the unit is at operating parameters, the shutter shall be controlled by the operator from the control panel. An indication of shutter position shall appear at the control panel.

7.12.f.13. Low Filtration X-ray Tubes. Each therapeutic radiation machine equipped with a beryllium or other low-filtration window shall be clearly labeled as such upon the tube housing assembly and shall be provided with a permanent warning device on the control panel that is activated when no additional filtration is present, to indicate that the dose rate is very high.

7.12.f.14. Facility design requirements for therapeutic radiation machines capable of operating in the range fifty (50) kV to five hundred (500) kV. In addition to shielding adequate to meet requirements of Subdivision 7.12.i., the treatment room shall meet the following design requirements:

7.12.f.14.A. Aural Communication. Provision shall be made for continuous two-way aural communication between the patient and the operator at the control panel;

7.12.f.14.B. Viewing Systems. Provision shall be made to permit continuous observation of the patient during irradiation and the viewing system shall be so located that the operator can observe the patient from the control panel. The therapeutic radiation machine shall not be used for patient irradiation unless at least one viewing system is operational.

7.12.f.15. Additional Requirements. Treatment rooms that contain a therapeutic radiation machine capable of operating above one hundred fifty (150) kV shall meet the following additional requirements:

7.12.f.15.A. All protective barriers shall be fixed except for entrance doors or beam interceptors;

7.12.f.15.B. The control panel shall be located outside the treatment room or in a totally enclosed booth, which has a ceiling, inside the room;

7.12.f.15.C. Interlocks shall be provided such that all entrance doors, including doors to any interior booths, shall be closed before treatment can be initiated or continued. If the radiation beam is interrupted by any door opening, it shall not be possible to restore the machine to operation without closing the door and reinitiating irradiation by manual action at the control panel; and

7.12.f.15.D. When any door referred to in Subparagraph 7.12.f.15.C. is opened while the x-ray tube is activated, the air kerma rate at a distance of one (1) meter from the source shall be reduced to less than one (1) mGy (one hundred [100] mRad) per hour.

7.12.f.16. Full Calibration Measurements.

7.12.f.16.A. Full calibration of a therapeutic radiation machine subject to Subdivision 7.12.f. shall be performed by, or under the direct supervision of, a radiation therapy physicist:

7.12.f.16.A.1. Before the first medical use following installation or reinstallation of the therapeutic radiation machine;

7.12.f.16.A.2. At intervals not exceeding one (1) year; and

7.12.f.16.A.3. Before medical use under the following conditions:

7.12.f.16.A.3.(a). When- ever quality assurance check measurements indicate that the radiation output differs by more than five (5) percent from the value obtained at the last full calibration and the difference cannot be reconciled; and

7.12.f.16.A.3.(b). Following any component replacement, major repair, or modification of components that could significantly affect the characteristics of the radiation beam.

7.12.f.16.A.4. Notwithstanding the requirements of Part 7.12.f.16.A.3.:

7.12.f.16.A.4.(a). Full calibration of therapeutic radiation machines with multi-energy capabilities is required only for those modes or energies that are not within their acceptable range; and

7.12.f.16.A.4.(b). If the repair, replacement or modification does not affect all energies, full calibration shall be performed on the affected energy that is in most frequent clinical use at the facility. The remaining energies may be validated with quality assurance check procedures against the criteria in subpart 7.12.f.16.A.3.(a).

7.12.f.16.B. To satisfy the requirement of Subparagraph 7.12.f.16.A., full calibration shall include all measurements recommended for annual calibration by NCRP Report 69, "Dosimetry of X-ray and Gamma Ray Beams for Radiation Therapy in the Energy Range 10 keV to 50 MeV" (1981).

7.12.f.16.C. The registrant shall maintain a record of each calibration for the duration of the registration. The record shall include: the date of the calibration; the manufacturer's name, model number, and serial number for both the therapeutic radiation machine and the x-ray tube; the model numbers and serial numbers of the instruments used to calibrate the therapeutic radiation machine; and the signature of the radiation therapy physicist responsible for performing the calibration.

7.12.f.17. Periodic Quality Assurance Checks.

7.12.f.17.A. Periodic quality assurance checks shall be performed on therapeutic radiation machines subject to Subdivision 7.12.f., which are capable of operation at greater than or equal to fifty (50) kV.

7.12.f.17.B. To satisfy the requirement of Subparagraph 7.12.f.17.A., quality assurance checks shall meet the following requirements:

7.12.f.17.B.1. The registrant shall perform quality assurance checks in accordance with written procedures established by the radiation therapy physicist.; and

7.12.f.17.B.2. The quality assurance check procedures shall specify the frequency at which tests or measurements are to be performed. The quality assurance check procedures shall specify that the quality assurance check shall be performed during the calibration specified in Subparagraph 7.12.f.16.A. The acceptable tolerance for each parameter measured in the quality assurance check, when compared to the value for that parameter determined in the calibration specified in Subparagraph 7.12.f.16.A., shall be stated.

7.12.f.17.C. The cause for a parameter exceeding a tolerance set by the radiation therapy physicist shall be investigated and corrected before the system is used for patient irradiation;

7.12.f.17.D. Whenever a quality assurance check indicates a significant change in the operating characteristics of a system, as specified in the radiation therapy physicist's quality assurance check procedures, the system shall be recalibrated as required in Subparagraph 7.12.f.16.A.;

7.12.f.17.E. The registrant shall use the dosimetry system described in Subparagraph 7.12.d.3.B. to make the quality assurance check required in Subparagraph 7.12.f.17.A.;

7.12.f.17.F. The registrant shall have the radiation therapy physicist review and sign the results of each radiation output quality assurance check within one (1) month of the date that the check was performed;

7.12.f.17.G. The registrant shall ensure that safety quality assurance checks of therapeutic radiation machines subject to Subdivision 7.12.f. are performed at intervals not to exceed one (1) month;

7.12.f.17.H. Notwithstanding the requirements of Subparagraphs 7.12.f.17.F. and Subparagraph 7.12.f.17.G., the registrant shall ensure that no therapeutic radiation machine is used to administer radiation to humans unless the quality assurance checks required by Subparagraphs 7.12.f.17.F. and Subparagraph 7.12.f.17.G. have been performed within the thirty (30) day period immediately prior to said administration;

7.12.f.17.I. To satisfy the requirement of Subparagraph 7.12.f.17.G., safety quality assurance checks shall ensure proper operation of:

7.12.f.17.I.1. Electrical interlocks at each external beam radiation therapy room entrance;

7.12.f.17.I.2. The "BEAM-ON" and termination switches;

7.12.f.17.I.3. Beam condition indicator lights on the access doors, control console, and in the radiation therapy room;

7.12.f.17.I.4. Viewing systems;

7.12.f.17.I.5. If applicable, electrically operated treatment room doors from inside and outside the treatment room.

7.12.f.17.J. The registrant shall maintain a record of each quality assurance check required by Subparagraph 7.12.f.17.A. and Subparagraph 7.12.f.17.g. for three (3) years. The record shall include: the date of the quality assurance check; the manufacturer's name, model number, and serial number of the therapeutic radiation machine; the manufacturer's name; model number and serial number for the instruments used to measure the radiation output of the therapeutic radiation machine; and the signature of the individual who performed the periodic quality assurance check.

7.12.f.18. Operating Procedures.

7.12.f.18.A. The therapeutic radiation machine shall not be used for irradiation of patients unless the requirements of Subparagraph 7.12.f.16. And Subparagraph 7.12.f.17. have been met;

7.12.f.18.B. Therapeutic radiation machines shall not be left unattended unless secured pursuant to Subparagraph 7.12.f.1.E.;

7.12.f.18.C. When a patient must be held in position for radiation therapy, mechanical supporting or restraining devices shall be used;

7.12.f.18.D. The tube housing assembly shall not be held by an individual during operation unless the assembly is designed to require such holding and the peak tube potential of the system does not exceed fifty (50) kV. In such cases, the holder shall wear protective gloves and apron of not less than five-tenths (0.5) millimeters lead equivalency at one hundred (100) kV;

7.12.f.18.E. A copy of the current operating and emergency procedures shall be maintained at the therapeutic radiation machine control console; and

7.12.f.18.F. No individual other than the patient shall be in the treatment room during exposures from therapeutic radiation machines operating above one hundred fifty (150) kV. At energies less than or equal to one hundred fifty (150) kV, any individual, other than the patient, in the treatment room shall be protected by a barrier sufficient to meet the requirements of Subsection 6.5 of this rule.

7.12.f.19. Possession of Survey Instruments. Each facility location authorized to use a therapeutic radiation machine in accordance with Subdivision 7.12.f. shall possess appropriately calibrated portable monitoring equipment. As a minimum, such equipment shall include a portable radiation measurement survey instrument capable of measuring dose rates over the range ten (10) :Sv (one [1] mRem) per hour to ten (10) mSv (one thousand [1000] mRem) per hour. The survey instruments shall be operable and calibrated in accordance with Subdivision 7.12.h.

7.12.g. Therapeutic Radiation Machines - photon therapy systems (five hundred [500] kV and above) and electron therapy systems (five hundred [500] keV and above).

7.12.g.1. Possession of Survey Instruments. Each facility location authorized to use a therapeutic radiation machine in accordance with Subdivision 7.12.g. shall possess appropriately calibrated portable monitoring equipment. As a minimum, such equipment shall include a portable radiation measurement survey instrument capable of measuring dose rates over the range ten (10) :Sv (one [1] mRem) per hour to ten (10) mSv (one thousand [1000] mRem) per hour. The survey instruments shall be operable and calibrated in accordance with Subsection 7.12.h.

7.12.g.2. Leakage Radiation Outside the Maximum Useful Beam in Photon and Electron Modes.

7.12.g.2.A. The absorbed dose due to leakage radiation (excluding neutrons) at any point outside the maximum sized useful beam, but within a circular plane of radius 2 meters which is perpendicular to and centered on the central axis of the useful beam at the nominal treatment distance (i.e. patient plane), shall not exceed a maximum of two-tenths (0.2) percent and an average of one-tenth (0.1) percent of the absorbed dose on the central axis of the beam at the nominal treatment distance. Measurements shall be averaged over an area not exceeding one hundred (100) square centimeters at a minimum of sixteen (16) points uniformly distributed in the plane;

7.12.g.2.B. Except for the area defined in Subparagraph 7.12.g.2.A., the absorbed dose due to leakage radiation (excluding neutrons) at one (1) meter from the electron path between the electron source and the target or electron window shall not exceed five-tenths (0.5) percent of the absorbed dose on the central axis of the beam at the nominal treatment distance. Measurements shall be averaged over an area not exceeding one hundred (100) square centimeters;

7.12.g.2.C. For equipment manufactured after July 1, 2001, the neutron absorbed dose outside the useful beam shall be in compliance with International Electrotechnical Commission (IEC) Document 601-2-1; and

7.12.g.2.D. For each therapeutic radiation machine, the registrant shall determine, or obtain from the manufacturer, the leakage radiation existing at the positions specified in Subparagraphs 7.12.g.2.A. through 7.12.g.2.C. for the specified operating conditions. Records on leakage radiation measurements shall be maintained at the installation for inspection by the agency.

7.12.g.3. Leakage Radiation Through Beam Limiting Devices.

7.12.g.3.A. Photon Radiation. All adjustable or interchangeable beam limiting devices shall attenuate the useful beam such that at the nominal treatment distance, the maximum absorbed dose anywhere in the area shielded by the beam limiting devices shall not exceed two (2) percent of the maximum absorbed dose on the central axis of the useful beam measured in a ten (10) centimeter by ten (10) centimeter radiation field;

7.12.g.3.B. Electron Radiation. All adjustable or interchangeable electron applicators shall attenuate the radiation, including but not limited to photon radiation generated by electrons incident on the beam limiting device and electron applicator and other parts of the radiation head, such that the absorbed dose in a plane perpendicular to the central axis of the useful beam at the nominal treatment distance shall not exceed:

7.12.g.3.B.1. A maximum of two (2) percent and average of five-tenths (0.5) percent of the absorbed dose on the central axis of the useful beam at the nominal treatment distance. This limit shall apply beyond a line seven (7) centimeters outside the periphery of the useful beam; and

7.12.g.3.B.2. A maximum of ten (10) percent of the absorbed dose on the central axis of the useful beam at the nominal treatment distance. This limit shall apply beyond a line two (2) centimeters outside the periphery of the useful beam..

7.12.g.3.C. Measurement of Leakage Radiation.

7.12.g.3.C.1. Photon Radiation. Measurements of leakage radiation through the beam limiting devices shall be made with the beam limiting devices closed and any residual aperture blocked by at least two (2) tenth value layers of suitable absorbing material. In the case of overlapping beam limiting devices, the leakage radiation through each set shall be measured independently at the depth of maximum dose. Measurements shall be made using a radiation detector of area not exceeding ten (10) square centimeters;

7.12.g.3.C.2. Electron Radiation. Measurements of leakage radiation through the electron applicators shall be made with the electron beam directed into the air and using a radiation detector of area up to but not exceeding one (1) square centimeter suitably protected against radiation which has been scattered from material beyond the radiation detector. Measurements shall be made using one (1) centimeter of water equivalent build up material.

7.12.g.4. Filters or Wedges.

7.12.g.4.A. Each wedge filter that is removable from the system shall be clearly marked with an identification number. For removable wedge filters, the nominal wedge angle shall appear on the wedge or wedge tray (if permanently mounted to the tray). If the wedge or wedge tray is significantly damaged, the wedge transmission factor shall be redetermined;

7.12.g.4.B. If the absorbed dose rate information required by Paragraph 7.12.g.1. relates exclusively to operation with a field flattening filter or beam scattering foil in place, such foil or filter shall be removable only by the use of tools;

7.12.g.4.C. For equipment manufactured after July 1, 2001 which utilizes wedge filters, interchangeable field flattening filters, or interchangeable beam scattering foils:

7.12.g.4.C.1. Irradiation shall not be possible until a selection of a filter or a positive selection to use "no filter" has been made at the treatment control panel, either manually or automatically;

7.12.g.4.C.2. An interlock system shall be provided to prevent irradiation if the filter selected is not in the correct position;

7.12.g.4.C.3. A display shall be provided at the treatment control panel showing the wedge filters, interchangeable field flattening filters, or interchangeable beam scattering foils in use; and

7.12.g.4.C.4. An interlock shall be provided to prevent irradiation if any filter or beam scattering foil selection operation carried out in the treatment room does not agree with the filter or beam scattering foil selection operation carried out at the treatment control panel.

7.12.g.5. Stray radiation in the useful beam. For equipment manufactured after July 1, 2001, the registrant shall determine during acceptance testing, or obtain from the manufacturer, data sufficient to ensure that x-ray stray radiation in the useful electron beam, absorbed dose at the surface during x-ray irradiation and stray neutron radiation in the useful x-ray beam are in compliance with International Electrotechnical Commission (IEC) Document 601-2-1 (most current revision).

7.12.g.6. Beam Monitors. All therapeutic radiation machines subject to Subdivision 7.12.g. shall be provided with redundant beam monitoring systems. The sensors for these systems shall be fixed in the useful beam during treatment to indicate the dose monitor unit rate.

7.12.g.6.A. Equipment manufactured after July 1, 2001 shall be provided with at least 2 independently powered integrating dose meters. Alternatively, common elements may be used if the production of radiation is terminated upon failure of any common element.

7.12.g.6.B. Equipment manufactured on or before July 1, 2001 shall be provided with at least one (1) radiation detector. This detector shall be incorporated into a useful beam monitoring system;

7.12.g.6.C. The detector and the system into which that detector is incorporated shall meet the following requirements:

7.12.g.6.C.1. Each detector shall be removable only with tools and, if movable, shall be interlocked to prevent incorrect positioning;

7.12.g.6.C.2. Each detector shall form part of a beam monitoring system from whose readings in dose monitor units the absorbed dose at a reference point can be calculated;

7.12.g.6.C.3. Each beam monitoring system shall be capable of independently monitoring, interrupting, and terminating irradiation; and

7.12.g.6.C.4. For equipment manufactured after July 1, 2001, the design of the beam monitoring systems shall ensure that the:

7.12.g.6.C.4.(a). Malfunctioning of one system shall not affect the correct functioning of the other systems; and

7.12.g.6.C.4.(b). Failure of either system shall terminate irradiation or prevent the initiation of radiation.

7.12.g.6.C.5. Each beam monitoring system shall have a legible display at the treatment control panel. For equipment manufactured after July 1, 2001, each display shall:

7.12.g.6.C.5.(a). Maintain a reading until intentionally reset;

7.12.g.6.C.5.(b). Have only one scale and no electrical or mechanical scale multiplying factors;

7.12.g.6.C.5.(c). Utilize a design such that increasing dose is displayed by increasing numbers; and

7.12.g.6.C.5.(d). In the event of power failure, the beam monitoring information required in Part 7.12.g.5.E.3. displayed at the control panel at the time of failure shall be retrievable in at least one system for a twenty (20) minute period of time.

7.12.g.7. Beam Symmetry.

7.12.g.7.A. Bent-beam linear accelerators subject to 7.12.g. shall be provided with auxiliary devices to monitor beam symmetry;

7.12.g.7.B. The devices referenced in Subparagraph 7.12.g.7.A. shall be able to detect field asymmetry greater than ten (10) percent; and

7.12.g.7.C. The devices referenced in Subparagraph 7.12.g.7.A. shall be configured to terminate irradiation if the specifications in Subparagraph 7.12.g.7.B. can not be maintained.

7.12.g.8. Selection and Display of Dose Monitor Units.

7.12.g.8.A. Irradiation shall not be possible until a new selection of a number of dose monitor units has been made at the treatment control panel;

7.12.g.8.B. The pre-selected number of dose monitor units shall be displayed at the treatment control panel until reset manually for the next irradiation;

7.12.g.8.C. After termination of irradiation, it shall be necessary to reset the dosimeter display before subsequent treatment can be initiated; and

7.12.g.8.D. For equipment manufactured after July 1, 2001, after termination of irradiation, it shall be necessary for the operator to reset the pre-selected dose monitor units before irradiation can be initiated.

7.12.g.9. Air Kerma Rate or Absorbed Dose Rate. For equipment manufactured after July 1, 2001, a system shall be provided from whose readings the air kerma rate or absorbed dose rate at a reference point can be calculated. In addition:.

7.12.g.9.A. The dose monitor unit rate shall be displayed at the treatment control panel;

7.12.g.9.B. If the equipment can deliver under any conditions an air kerma rate or absorbed dose rate at the nominal treatment distance more than twice the maximum value specified by the manufacturer, a device shall be provided which terminates irradiation when the air kerma rate or absorbed dose rate exceeds a value twice the specified maximum. The dose rate at which the irradiation will be terminated shall be a record maintained by the registrant;

7.12.g.9.C. If the equipment can deliver under any fault condition or conditions an air kerma rate or absorbed dose rate at the nominal treatment distance more than ten (10) times the maximum value specified by the manufacturer, a device shall be provided to prevent the air kerma rate or absorbed dose rate anywhere in the radiation field from exceeding twice the specified maximum value and to terminate irradiation if the excess absorbed dose at the nominal treatment distance exceeds four (4) Gy (four hundred [400] Rad); and

7.12.g.9.D. For each therapeutic radiation machine, the registrant shall determine, or obtain from the manufacturer, the maximum values specified in 7.12.g.9.B. and 7.12.g.9.C. for the specified operating conditions. Records of these maximum values shall be maintained at the installation for inspection by the agency.

7.12.g.10. Termination of irradiation by the beam monitoring system or systems during stationary beam radiation therapy.

7.12.g.10.A. Each primary system shall terminate irradiation when the pre-selected number of dose monitor units has been detected by the system;

7.12.g.10.B. If the original design of the equipment included a secondary dose monitoring system, that system shall be capable of terminating irradiation when not more than fifteen (15) percent or forty (40) dose monitor units above the pre-selected number of dose monitor units set at the control panel has been detected by the secondary dose monitoring system; and

7.12.g.10.C. For equipment manufactured after July 1, 2001, an indicator on the control panel shall show which monitoring system has terminated irradiation.

7.12.g.11. Termination of Irradiation. It shall be possible to terminate irradiation and equipment movement or go from an interruption condition to termination condition at any time from the operator's position at the treatment control panel.

7.12.g.12. Interruption of Irradiation. If a therapeutic radiation machine has an interrupt mode, it shall be possible to interrupt irradiation and equipment movements at any time from the treatment control panel. Following an interruption it shall be possible to restart irradiation by operator action without any reselection of operating conditions. If any change is made of a pre-selected value during an interruption, irradiation and equipment movements shall be automatically terminated.

7.12.g.13. Timer. A suitable irradiation control device shall be provided to terminate the irradiation after a pre-set time interval.

7.12.g.13.A. A timer shall be provided which has a display at the treatment control panel. The timer shall have a pre-set time selector and an elapsed time indicator;

7.12.g.13.B. The timer shall be a cumulative timer that activates with an indication of "BEAM-ON" and retains its reading after irradiation is interrupted or terminated. After irradiation is terminated and before irradiation can be reinitiated, it shall be necessary to reset the elapsed time indicator;

7.12.g.13.C. The timer shall terminate irradiation when a pre-selected time has elapsed, if the dose monitoring systems have not previously terminated irradiation.

7.12.g.14. Selection of Radiation Type. Equipment capable of both x-ray therapy and electron therapy shall meet the following additional requirements:

7.12.g.14.A. Irradiation shall not be possible until a selection of radiation type (x-rays or electrons) has been made at the treatment control panel;

7.12.g.14.B. The radiation type selected shall be displayed at the treatment control panel before and during irradiation;

7.12.g.14.C. An interlock system shall be provided to ensure that the equipment can principally emit only the radiation type that has been selected;

7.12.g.14.D. An interlock system shall be provided to prevent irradiation with x-rays, except to obtain an image, when electron applicators are fitted;

7.12.g.14.E. An interlock system shall be provided to prevent irradiation with electrons when accessories specific for x-ray therapy are fitted; and

7.12.g.14.F. An interlock system shall be provided to prevent irradiation if any selected operations carried out in the treatment room do not agree with the selected operations carried out at the treatment control panel.

7.12.g.15. Selection of Energy. Equipment capable of generating radiation beams of different energies shall meet the following requirements:

7.12.g.15.A. Irradiation shall not be possible until a selection of energy has been made at the treatment control panel;

7.12.g.15.B. The nominal energy value selected shall be displayed at the treatment control panel until reset manually for the next irradiation. After termination of irradiation, it shall be necessary to reset the nominal energy value selected before subsequent treatment can be initiated;

7.12.g.15.C. Irradiation shall not be possible until the appropriate flattening filter or scattering foil for the selected energy is in its proper location; and

7.12.g.15.D. For equipment manufactured after July 1, 2001, the selection of energy shall be in compliance with International Electrotechnical Commission (IEC) Document 601-2-1.

7.12.g.16. Selection of Stationary Beam Radiation Therapy or Moving Beam Radiation Therapy. Therapeutic radiation machines capable of both stationary beam radiation therapy and moving beam radiation therapy shall meet the following requirements:

7.12.g.16.A. Irradiation shall not be possible until a selection of stationary beam radiation therapy or moving beam radiation therapy has been made at the treatment control panel;

7.12.g.16.B. The mode of operation shall be displayed at the treatment control panel;

7.12.g.16.C. An interlock system shall be provided to ensure that the equipment can operate only in the mode that has been selected;

7.12.g.16.D. An interlock system shall be provided to prevent irradiation if any selected parameter in the treatment room does not agree with the selected parameter at the treatment control panel;

7.12.g.16.E. Moving beam radiation therapy shall be controlled to obtain the selected relationships between incremental dose monitor units and incremental movement. For equipment manufactured after July 1, 2001:

7.12.g.16.E.1. An interlock system shall be provided to terminate irradiation if the number of dose monitor units delivered in any ten (10) degrees of rotation or one (1) cm of linear motion differs by more than twenty (20) percent from the selected value;

7.12.g.16.E.2. Where angle terminates the irradiation in moving beam radiation therapy, the dose monitor units delivered shall differ by less than five (5) percent from the dose monitor unit value selected;

7.12.g.16.E.3. An interlock shall be provided to prevent motion of more than five (5) degrees or one (1) cm beyond the selected limits during moving beam radiation therapy;

7.12.g.16.E.4. An interlock shall be provided to require that a selection of direction be made at the treatment control panel in all units which are capable of both clockwise and counter-clockwise moving beam radiation therapy.

7.12.g.16.E.5. Moving beam radiation therapy shall be controlled with both primary position sensors and secondary position sensors to obtain the selected relationships between incremental dose monitor units and incremental movement.

7.12.g.16.E.6. Where the beam monitor system terminates the irradiation in moving beam radiation therapy, the termination of irradiation shall be as required by Paragraph 7.12.g.10.; and

7.12.g.16.E.7. For equipment manufactured after July 1, 2001, an interlock system shall be provided to terminate irradiation if movement:

7.12.g.16.E.7.(a). Occurs during stationary beam radiation therapy; or

7.12.g.16.E.7.(b). Does not start or stops during moving beam radiation therapy unless such stoppage is a pre-planned function.

7.12.g.17. Facility Design Requirements for Therapeutic Radiation Machines Operating Above 500 kV. In addition to shielding adequate to meet requirements of 1.12.i., the following design requirements are made:

7.12.g.17.A. Protective Barriers. All protective barriers shall be fixed, except for access doors to the treatment room or movable beam interceptors;

7.12.g.17.B. Control Panel. In addition to other requirements specified in Subsection 7.12., the control panel shall also:

7.12.g.17.B.1. Be located outside the treatment room;

7.12.g.17.B.2. Provide an indication of whether electrical power is available at the control panel and if activation of the radiation is possible;

7.12.g.17.B.3. Provide an indication of whether radiation is being produced; and

7.12.g.17.B.4. Include an access control (locking) device that will prevent unauthorized use of the therapeutic radiation machine.

7.12.g.17.C. Viewing Systems. Windows, mirrors, closed-circuit television or an equivalent viewing system shall be provided to permit continuous observation of the patient following positioning and during irradiation and shall be so located that the operator may observe the patient from the treatment control panel. The therapeutic radiation machine shall not be used for patient irradiation unless at least one viewing system is operational;

7.12.g.17.D. Aural Communications. Provision shall be made for continuous two-way aural communication between the patient and the operator at the control panel. The therapeutic radiation machine shall not be used for irradiation of patients unless continuous two-way aural communication is possible;

7.12.g.17.E. Room Entrances. Treatment room entrances shall be provided with warning lights in a readily observable position near the outside of all access doors, which will indicate when the useful beam is "ON" and when it is "OFF";

7.12.g.17.F. Entrance Interlocks. Interlocks shall be provided such that all access controls are activated before treatment can be initiated or continued. If the radiation beam is interrupted by any access control, it shall not be possible to restore the machine to operation without resetting the access control and reinitiating irradiation by manual action at the control panel;

7.12.g.17.G. Beam Interceptor Interlocks. If the shielding material in any protective barrier requires the presence of a beam interceptor to ensure compliance with Subdivision 6.13.a. and Subsection 6.13.b. of this rule, interlocks shall be provided to prevent the production of radiation, unless the beam interceptor is in place, whenever the useful beam is directed at the designated barriers;

7.12.g.17.H. Emergency Cutoff Switches. At least 1 emergency power cutoff switch shall be located in the radiation therapy room and shall terminate all equipment electrical power including radiation and mechanical motion. This switch is in addition to the termination switch required by 7.12.g.11. All emergency power cutoff switches shall include a manual reset so that the therapeutic radiation machine cannot be restarted from the unit's control console without resetting the emergency cutoff switch;

7.12.g.17.I. Safety Interlocks. All safety interlocks shall be designed so that any defect or component failure in the safety interlock system prevents or terminates operation of the therapeutic radiation machine; and

7.12.g.17.J. Surveys for Residual Radiation. Surveys for residual activity shall be conducted on all therapeutic radiation machines capable of generating photon and electron energies above ten (10) MV prior to machining, removing, or working on therapeutic radiation machine components which may have become activated due to photo-neutron production.

7.12.g.18. Radiation Therapy Physicist Support.

7.12.g.18.A. The services of a radiation therapy physicist shall be required in facilities having therapeutic radiation machines with energies of five hundred (500) kV and above. The radiation therapy physicist shall be responsible for:

7.12.g.18.A.1. Full calibrations required by Paragraph 7.12.g.20. and protection surveys required by Paragraph 7.12.d.1.;

7.12.g.18.A.2. Supervision and review of dosimetry;

7.12.g.18.A.3. Beam data acquisition and transfer for computerized dosimetry, and supervision of its use;

7.12.g.18.A.4. Quality assurance, including quality assurance check review required by Subparagraph 7.12.g.21.E.

7.12.g.18.A.5. Consultation with the authorized user in treatment planning, as needed; and

7.12.g.18.A.6. Perform calculations/assessments regarding misadministrations.

7.12.g.18.B. If the radiation therapy physicist is not a full-time employee of the registrant, the operating procedures required by Subparagraph 7.12.g.24. shall also specifically address how the radiation therapy physicist is to be contacted for problems or emergencies, as well as the specific actions, if any, to be taken until the radiation therapy physicist can be contacted.

7.12.g.19. Operating Procedures.

7.12.g.19.A. No individual, other than the patient, shall be in the treatment room during treatment or during any irradiation for testing or calibration purposes;

7.12.g.19.B. Therapeutic radiation machines shall not be made available for medical use unless the requirements of 7.12.a.1., 7.12.g.20. and 7.12.21. have been met;

7.12.g.19.C. Therapeutic radiation machines, when not in operation, shall be secured to prevent unauthorized use;

7.12.g.19.D. When adjustable beam limiting devices are used, the position and shape of the radiation field shall be indicated by a light field.

7.12.g.19.E. If a patient must be held in position during treatment, mechanical supporting or restraining devices shall be used; and

7.12.g.19.F. A copy of the current operating and emergency procedures shall be maintained at the therapeutic radiation machine control console.

7.12.g.20. Acceptance testing, commissioning and full calibration measurements.

7.12.g.20.A. Acceptance testing, commissioning and full calibration of a therapeutic radiation machine subject to Subsection 7.12. shall be performed by, or under the direct supervision of, a radiation therapy physicist.

7.12.g.20.B. Acceptance testing and commissioning shall be performed in accordance with "AAPM Code of Practice for Radiotherapy Accelerators: Report of AAPM Radiation Therapy Task Group 45" and shall be conducted before the first medical use following installation or reinstallation of the therapeutic radiation machine.

7.12.g.20.C. Full calibration shall include measurement of all parameters required by Table II of "Comprehensive QA for Radiation Oncology: Report of AAPM Radiation Therapy Committee Task Group 40" and shall be performed in accordance with "AAPM Code of Practice for Radiotherapy Accelerators: Report of AAPM Radiation Therapy Task Group 45". Although it shall not be necessary to complete all elements of a full calibration at the same time, all parameters (for all energies) shall be completed at intervals not exceeding twelve (12) calendar months, unless a more frequent interval is required in Table ii.

7.12.g.20.D. The radiation therapy physicist shall perform all elements of a full calibration necessary to determine that all parameters are within acceptable limits:

7.12.g.20.D.1. Whenever quality assurance check measurements indicate that the radiation output differs by more than five (5) percent from the value obtained at the last full calibration and the difference cannot be reconciled. Therapeutic radiation machines with multi-energy or multi-mode capabilities shall only require measurements for those modes or energies that are not within their acceptable range; and

7.12.g.20.D.2. Following any component replacement, major repair, or modification of components that could significantly affect the characteristics of the radiation beam. If the repair, replacement or modification does not affect all modes or energies, measurements shall be performed on the effected mode or energy that is in most frequent clinical use at the facility. The remaining energies or modes may be validated with quality assurance check procedures against the criteria in 7.12.g.20.D.1.

7.12.g.20.E. The registrant shall maintain a record of each calibration in an auditable form for the duration of the registration. The record shall include: the date of the calibration; the manufacturer's name, model number and serial number for the therapeutic radiation machine; the model numbers and serial numbers of the instruments used to calibrate the therapeutic radiation machine; and the signature of the radiation therapy physicist responsible for performing the calibration.

7.12.g.21. Periodic Quality Assurance Checks.

7.12.g.21.A. Periodic quality assurance checks shall be performed on all therapeutic radiation machines subject to Subdivision 7.12. at intervals not to exceed those specified in "comprehensive qa for radiation oncology: report of AAPM radiation therapy committee task group 40";

7.12.g.21.B. To satisfy the requirement of Subparagraph 7.12.g.21.A., quality assurance checks shall include determination of central axis radiation output and a representative sampling of periodic quality assurance checks contained in "comprehensive qa for radiation oncology: report of AAPM radiation therapy committee task group 40". Representative sampling shall include all referenced periodic quality assurance checks in an interval not to exceed 12 consecutive calendar months;

7.12.g.21.C. The registrant shall use a dosimetry system that has been inter-compared within the previous 12 months with the dosimetry system described in Subparagraph 7.12.d.3.A. to make the periodic quality assurance checks required in Subparagraphs 7.12.g.21.B.;

7.12.g.21.D. The registrant shall perform periodic quality assurance checks required by Subparagraph 7.12.g.21.A. in accordance with procedures established by the radiation therapy physicist;

7.12.g.21.E. The registrant shall review the results of each periodic radiation output check according to the following procedures:

7.12.g.21.E.1. The authorized user and radiation therapy physicist shall be immediately notified if any parameter is not within its acceptable tolerance. The therapeutic radiation machine shall not be made available for subsequent medical use until the radiation therapy physicist has determined that all parameters are within their acceptable tolerances;

7.12.g.21.E.2. If all quality assurance check parameters appear to be within their acceptable range, the quality assurance check shall be reviewed and signed by either the authorized user or radiation therapy physicist within three (3) treatment days; and

7.12.g.21.E.3. The radiation therapy physicist shall review and sign the results of each radiation output quality assurance check at intervals not to exceed one (1) month.

7.12.g.21.F. Therapeutic radiation machines subject to Subsection 7.12. shall have safety quality assurance checks listed in "Comprehensive QA for Radiation Oncology: Report of AAPM Radiation Therapy Committee Task Group 40" performed at intervals not to exceed one (1) week;

7.12.g.21.G. To satisfy the requirement of Subparagraph 7.12.g.21.F., safety quality assurance checks shall ensure proper operation of:

7.12.g.21.G.1. Electrical interlocks at each external beam radiation therapy room entrance;

7.12.g.21.G.2. Proper operation of the "BEAM-ON", interrupt and termination switches;

7.12.g.21.G.3. Beam condition indicator lights on the access doors, control console, and in the radiation therapy room;

7.12.g.21.G.4. Viewing systems;

7.12.g.21.G.5. Electrically operated treatment room doors from inside and outside the treatment room;

7.12.g.21.G.6. At least one emergency power cutoff switch. If more than one emergency power cutoff switch is installed and not all switches are tested at once, each switch shall be tested on a rotating basis. Safety quality assurance checks of the emergency power cutoff switches may be conducted at the end of the treatment day in order to minimize possible stability problems with the therapeutic radiation machine.

7.12.g.21.H. The registrant shall promptly repair any system identified in Subparagraph 7.12.g.21.G. that is not operating properly; and

7.12.g.21.I. The registrant shall maintain a record of each quality assurance check required by Subparagraphs 7.12.g.21.A. and 7.21.g.21.G. for three (3) years. The record shall include: the date of the quality assurance check; the manufacturer's name, model number, and serial number of the therapeutic radiation machine; the manufacturer's name, model number and serial number for the instruments used to measure the radiation output of the therapeutic radiation machine; and the signature of the individual who performed the periodic quality assurance check.

7.12.h. Calibration of Survey Instruments.

7.12.h.1. The registrant shall ensure that the survey instruments used to show compliance with Subsection 7.12. have been calibrated before first use, at intervals not to exceed twelve (12) months, and following repair.

7.12.h.2. To satisfy the requirements of Paragraph 7.12.h.1., the registrant shall:

7.12.h.2.A. Calibrate all required scale readings up to ten (10) mSv (one thousand [1000] mRem) per hour with an appropriate radiation source that is traceable to the National Institute of Standards and Technology (NIST);

7.12.h.2.B. Calibrate at least two (2) points on each scale to be calibrated. These points should be at approximately one-third (1/3) and two-thirds (2/3) of full-scale; and

7.12.h.3. To satisfy the requirements of Paragraph 7.12.h.2., the registrant shall:

7.12.h.3.B. Consider a point as calibrated if the indicated dose rate differs from the calculated dose rate by not more than ten (10) percent; and

7.12.h.3.C. Consider a point as calibrated if the indicated dose rate differs from the calculated dose rate by not more than twenty (20) percent if a correction factor or graph is conspicuously attached to the instrument.

7.12.h..3.D. The registrant shall retain a record of each calibration required in Paragraph 7.12.h.1. for three (3) years. The record shall include:

7.12.h.3.D.1. A description of the calibration procedure; and

7.12.h.3.D.2. A description of the source used and the certified dose rates from the source, and the rates indicated by the instrument being calibrated, the correction factors deduced from the calibration data, the signature of the individual who performed the calibration, and the date of calibration.

7.12.h.3.E. The registrant may obtain the services of individuals registered by the agency, the US Nuclear Regulatory Commission, an agreement state, or a licensing state to perform calibrations of survey instruments. Records of calibrations that contain information required by Paragraph 7.12.h.4. shall be maintained by the registrant.

7.12.i. Shielding and Safety Design Requirements.

7.12.i.1. Each therapeutic radiation machine subject to Subdivision 7.12.g. or 7.12.h. shall be provided with such primary or secondary barriers as are necessary to ensure compliance with Subsections 6.5. and 6.13. of this rule.

7.12.i.2. Facility design information for all new installations of a therapeutic radiation machine or installations of a therapeutic radiation machine of higher energy into a room not previously approved for that energy shall be submitted for agency approval prior to actual installation of the therapeutic radiation machine. The minimum facility design information that must be submitted is contained in Table 64-23 U.

Notes

W. Va. Code R. § 64-23-7

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