Utah Code R313-28-35 - General Requirements for Diagnostic X-Ray Systems

In addition to other requirements of Rule R313-28, each diagnostic x-ray system shall meet the requirements in Section R313-28-35.

(1) 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."

(2) Battery charge indicator. On battery powered generators visual means shall be provided on the control panel to show whether the battery is in a state of charge adequate for proper operation.

(3) Leakage radiation from the diagnostic source assembly. The leakage radiation from the diagnostic source assembly measured at a distance of one meter in any direction from the source may not exceed 25.8 uC/kg, 100 milliroentgens, in one hour if the x-ray tube is operated at its leakage technique factors.

(4) Radiation from components other than the diagnostic source assembly. The radiation emitted by a component other than the diagnostic source assembly may not exceed 0.516 uC/kg, two milliroentgens, in one hour at five centimeters from accessible surfaces of the component if it is operated in an assembled x-ray system under the conditions that it was designed to operate under. Compliance shall be determined by measurements averaged over an area of 100 square centimeters with no linear dimension greater than 20 centimeters.

(5) Beam quality.

(a) The half-value layer of the useful beam for a given x-ray tube potential may not be less than the values shown in Section R313-28-35, Table 1. If it is necessary to determine the half-value layer at an x-ray tube potential that is not listed in Table 1, linear interpolation or extrapolation may be made.

Table 1
Design Operating Range (Kilovolts Peak)	Measured Potential (Kilovolts Peak)	Dental Intra-Oral Manufactured Before August 1, 1974 and On or Before December 1, 1980	All Other Diagnostic X-Ray Systems
Below 51	30	(use prohibited)	0.3
	40	(use prohibited)	0.4
	50	1.5	0.5
	51	1.5	1.2
	60	1.5	1.3
	70	1.5	1.5
Above 70	71	2.1	2.1
	80	2.3	2.3
	90	2.5	2.5
	100	2.7	2.7
	110	3.0	3.0
	120	3.2	3.2
	130	3.5	3.5
	140	3.8	3.8
	150	4.1	4.1

(b) For capacitor discharge equipment compliance with the requirements of Subsection R313-28-35(5)(a) shall be determined with the system fully charged and a setting of 10 mAs for exposures.

(c) The required minimal half-value layer of the useful beam shall include the filtration contributed by materials that are permanently present between the focal spot of the tube and the patient.

(d) Filtration control. For x-ray systems that have variable kVp and variable filtration for the useful beam a device shall link the kVp selector with the filters and shall prevent an exposure unless the minimum amount of filtration necessary to produce the HVL required by Subsection R313-28-35(5)(a) is in the useful beam for the given kVp that has been selected.

(6) Multiple tubes. If two or more radiographic tubes are controlled by one exposure switch the tube or tubes that have been selected shall be clearly shown before initiation of the exposure. For equipment manufactured after August 1, 1974, indications shall be both on the x-ray control panel and at or near the tube housing assembly that has been selected.

(7) Mechanical support of tube head. The tube housing assembly supports shall be adjusted so that the tube housing assembly will remain stable during an exposure unless the tube housing movement during exposure is a designed function of the x-ray system.

(8) Technique indicators.

(a) The technique factors to be used during an exposure shall be shown before the exposure begins, except when automatic EXPOSURE controls are used, in that case the technique factors that are set before the exposure shall be indicated.

(b) On equipment having fixed technique factors the requirements in Subsection R313-28-35(8)(a) may be met by permanent markings. Indication of technique factors shall be visible from the operator's position except in the case of spot films made by the fluoroscopist.

(9) Maintaining compliance. Diagnostic x-ray systems and their associated components certified pursuant to the provisions of 21 CFR Part 1020 (2006) shall be maintained in compliance with applicable requirements of that standard.

(10) Locks. Each position locking, holding, and centering device on x-ray system components and systems shall function as intended.

(11) X-ray systems that have been granted a variance by the Director, Center for Devices and Radiological Health, Food and Drug Administration (Director), from the performance standards for ionizing radiation emitting products in accordance with 21 CFR 1010.4 (2006) shall be accepted as satisfying the requirements in Rule R313-28 that correspond to the variance granted by the Director. The registrant shall insure that labeling pursuant to 21 CFR 1010.5(f) (2006) remains legible and visible on the x-ray system.

Notes

Utah Code R313-28-35

Amended by Utah State Bulletin Number 2025-08, effective 4/14/2025