In addition to other requirements of R313-28, all diagnostic
x-ray systems shall meet the following requirements:
(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 indicate 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 shall not exceed 25.8 uC/kg (100 milliroentgens) in one hour
when 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 shall not exceed 0.516 uC/kg (two milliroentgens) in
one hour at five centimeters from accessible surfaces of the component when it
is operated in an assembled x-ray system under the conditions for which it was
designed. 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 shall not be less than the values shown in
R313-28-35, Table I. 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.
|
TABLE I
|
|
DESIGN
OPERATING
RANGE (KILO
VOLTS PEAK
|
MEASURED
POTENTIAL
(KILOVOLTS PEAK)
|
DENTAL INTRA-ORAL
MANUFACTURED BEFORE
AUGUST 1, 1974 AND ON OR AFTER
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
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 which are
permanently present between the focal spot of the tube and the
patient.
(d) Filtration control.
For x-ray systems which 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 R313-28-35(5)(a) is in the useful beam for the
given kVp which has been selected.
(6) Multiple tubes. When 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. 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 which
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 indicated before the exposure begins, except when
automatic EXPOSURE controls are used, in which case the technique factors which
are set prior to the exposure shall be indicated.
(b) On equipment having fixed technique
factors, the requirements, in 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. All position locking, holding,
and centering devices on x-ray system components and systems shall function as
intended.
(11) X-ray systems which
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 deemed
to satisfy the requirements in 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.