Washington Administrative Code › Title 246 - Health, Department of › RADIATION › Chapter 246-225 - Radiation protection - X rays in the healing arts › Section 246-225-040 - General requirements for diagnostic X-ray systems

Current through Register Vol. 24-14, July 15, 2024
In addition to other requirements of this chapter, 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 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 1 meter in any direction from the
				source, shall not exceed 2.58 x 10
-5
coulombs per kilogram (100 milliroentgens) in one 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 square centimeters with no
				linear dimension greater than twenty centimeters.
(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 5.16 x
				10
-7
coulombs per kilogram (2
				milliroentgens) in one hour at 5 centimeters from an accessible surface of the
				component when it is operated in an assembled X-ray system under 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
				(HVL) of the useful beam for a given X-ray tube potential shall not be less
				than the values shown in this section, 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 shall be made.
WAC
				  246-225-040 TABLE 1
Design
operating
range
(kilovolts peak)
Measured
potential
(kilovolts
peak)
Half-value
layer (milli-
meters of
aluminum
equivalent)
Half-value
layer (milli-
meter of
aluminum
equivalent
for dental units)
Below 51--
30
0.3
N/A
40
0.4
N/A
50
0.5
1.5
51 to 70---
51
1.2
1.5
60
1.3
1.5
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 energy storage equipment, compliance shall be determined with the
				system fully charged and a setting of at least 10 mAs for each
				exposure.
(c) The required minimal
				half-value layer shall include the filtration contributed by materials
				permanently in position between the focal spot of the tube and the patient.
				(For example, a table top when the tube is mounted "under the table" and
				inherent filtration of the tube.)
(d) Filtration control. For X-ray systems
				with 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 required by subdivision (a) of this subsection is
				in the useful beam for the selected kVp.