Virginia Administrative Code › Title 12 - HEALTH › Agency 5 - DEPARTMENT OF HEALTH › Chapter 481 - VIRGINIA RADIATION PROTECTION REGULATIONS › Part VI - Use Of Diagnostic X-Rays In The Healing Arts › Section 12VAC5-481-1601 - General requirements for all diagnostic x-ray systems

Current through Register Vol. 40, No. 24, July 15, 2024
In addition to other requirements of this part, 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, operating instructions, and maintenance
					 schedules are observed."
2.
				  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 0.88 milligray (mGy) air kerma (100
				  milliroentgen (mR) exposure) in one hour when the x-ray tube is operated at its
				  leakage technique factors. If the maximum rated peak tube potential of the tube
				  housing assembly is greater than the maximum rated peak tube potential for the
				  diagnostic source assembly, positive means shall be provided to limit the
				  maximum x-ray tube potential to that of the diagnostic source assembly.
				  Compliance shall be determined by measurements averaged over an area of 100
				  square cm with no linear dimension greater than 20 cm.
3. Radiation from components other than the
				  diagnostic source assembly. The radiation emitted by a component other than the
				  diagnostic source assembly shall not exceed an air kerma of 18 microgray (two
				  milliroentgens exposure) in one hour at five cm 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 100 square cm with no linear dimension
				  greater than 20 cm.
4. Beam quality
				  half-value layer (HVL).
a. The HVL of the
				  useful beam for a given x-ray tube potential shall not be less than the values
				  shown in Table 1 (i)under the heading "Specified Dental Systems" for any dental
				  x-ray system designed for use with intraoral image receptors and manufactured
				  after December 1, 1980; (ii)under the heading "I-Other X-Ray Systems" for any
				  dental x-ray system designed for use with intraoral image receptors and
				  manufactured before or on December 1, 1980, and all other x-ray systems subject
				  to this section and manufactured before June 10, 2006; and (iii)under the
				  heading "II-Other X-Ray Systems" for all x-ray systems, except dental x-ray
				  systems designed for use with intraoral image receptors, subject to this
				  section and manufactured on or after June 10, 2006. If it is necessary to
				  determine such half-value layer at an x-ray tube potential that is not listed
				  in Table 1, linear interpolation or extrapolation may be made. Positive means
				  shall be provided to ensure that at least the minimum filtration needed to
				  achieve beam quality requirements is in the useful beam during each exposure.
				  In the case of a system, which is to be operated with more than one thickness
				  of filtration, this requirement can be met by a filter interlocked with the
				  kilovoltage selector that will prevent x-ray emissions if the minimum required
				  filtration is not in place.
TABLE 1
X-Ray Tube Voltage (kilovolt peak)
Design Operating Range
Measured Operating Potential
Minimum HVL (mm in Aluminum)
Specified Dental Systems1
I-Other X-Ray Systems2
II-Other X-Ray Systems3
Below 51
30
1.5
0.3
0.3
40
1.5
0.4
0.4
50
1.5
0.5
0.5
51 to 70
51
1.5
1.2
1.3
60
1.5
1.3
1.5
70
1.5
1.5
1.8
Above 70
71
2.1
2.1
2.5
80
2.3
2.3
2.9
90
2.5
2.5
3.2
100
2.7
2.7
3.6
110
3.0
3.0
3.9
120
3.2
3.2
4.3
130
3.5
3.5
4.7
140
3.8
3.8
5.0
150
4.1
4.1
5.4
1 Dental x-ray systems
							 designed for use with intraoral image receptors and manufactured after December
							 1, 1980. 
							 2 Dental x-ray systems
							 designed for use with intraoral image receptors and manufactured before or on
							 December 1, 1980, and all other x-ray systems subject to this section and
							 manufactured before June 10, 2006. 
							 3 All x-ray systems, except
							 dental x-ray systems designed for use with intraoral image receptors, subject
							 to this section and manufactured on or after June 10, 2006.
b.
				  Optional filtration. Fluoroscopic systems manufactured on or after June 10,
				  2006, incorporating an x-ray tube or tubes with a continuous output of one
				  kilowatt or more and an anode heat storage capacity of one million heat units
				  or more shall provide the option of adding x-ray filtration to the diagnostic
				  source assembly in addition to the amount needed to meet the half-value layer
				  provisions in Table 1. The selection of this additional x-ray filtration shall
				  be either at the option of the user or automatic as part of the selected mode
				  of operation. A means of indicating which combination of additional filtration
				  is in the x-ray beam shall be provided.
c. Measuring compliance. For capacitor energy
				  storage equipment, compliance shall be determined with the maximum selectable
				  quantity of charge per exposure.