North Carolina Administrative Code › Title 10A - HEALTH AND HUMAN SERVICES › Chapter 15 - RADIATION PROTECTION › Section .0600 - X RAYS IN THE HEALING ARTS › Section 15 .0604 - GENERAL REQUIREMENTS FOR ALL DIAGNOSTIC SYSTEMS

Current through Register Vol. 39, No. 2, July 15, 2024
(a) In addition
				to other requirements of this Section, all diagnostic x-ray systems shall meet
				the following requirements:
(1) 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 operation instructions
				are observed."
(2) Equivalent
				wording may be used 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) The leakage radiation from the diagnostic
				source assembly measured at a distance of one meter in any direction from the
				source shall not exceed 100 millirem 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 100 square centimeters with no linear
				dimension greater than 20 centimeters.
(4) The radiation emitted by a component
				other than the diagnostic source assembly shall not exceed two millirem in one
				hour at five 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 100 square centimeters with no linear dimension greater than 20
				centimeters.
(5) Beam Quality
(A) Half-Value Layer
(i) The half-value layer (HVL) of the useful
				beam for a given x-ray tube potential shall not be less than the appropriate
				value shown in the following table. "Specified Dental System" is any dental
				x-ray system designed for use with intraoral image receptors and manufactured
				after December 1, 1980. "Other X-Ray Systems" shall be all other x-ray systems
				subject to this Section.
X-Ray Tube Voltage
(kilovolt peak)
Minimum HVL (millimeters of Aluminum)
Minimum HVL (millimeters of Aluminum)
Designed operating range
Measured Operating Potential
Specified Dental Systems
Other X-ray Systems
Below 50------------
30
1.5
0.3
40
1.5
0.4
49
1.5
0.5
50 to 70------------
50
1.5
1.2
60
1.5
1.2
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
If it is necessary to determine such half-value layer at an
				  x-ray tube potential which is not listed in the table, linear interpolation or
				  extrapolation may be made. Positive means shall be provided to insure that at
				  least the minimum filtration needed to achieve the above beam quality
				  requirements is in the useful beam during each exposure.
(ii) The requirements of Subpart (a)(5)(A)(i)
				of this Rule shall be considered to be met if it can be demonstrated that the
				aluminum equivalent of the total filtration in the primary beam is not less
				than that shown in the following table:
Filtration Required versus Operating
							 Voltage
Operating Voltage (kVp)
Minimum total filtration (inherent plus
							 added)
(millimeters aluminum equivalent)
Below 50
0.5 millimeters
50 - 70
1.5 millimeters
Above 70
2.5 millimeters
(iii) Notwithstanding the requirements of
				Subpart (a)(5)(A)(ii) of this Rule, all intraoral dental systems manufactured
				after December 1, 1980, shall have a minimum of 1.5 mm aluminum equivalent
				filtration permanently installed in the useful beam.
(iv) Beryllium window tubes shall have a
				minimum of 0.5 mm aluminum equivalent filtration permanently mounted in the
				useful beam.
(v) For capacitor
				energy storage equipment, compliance shall be determined with the maximum
				quantity of charge per exposure.
(vi) The required minimum aluminum equivalent
				filtration shall include the filtration contributed by all materials which are
				always present between the focal spot of the tube and the patient, such as a
				tabletop when the tube is mounted under the table and inherent filtration of
				the tube.
(B) For new
				x-ray systems installed after the effective date of these Rules and which have
				variable kVp and selectable filtration for the useful beam, a device shall link
				the kVp selector with the filter(s), so that the minimum filtration is always
				present for the kVp selected.
(6) Where two or more radiographic tubes are
				controlled by one exposure switch, the tube or tubes which have been selected
				and their location shall be clearly indicated on the master control panel prior
				to initiation of the exposure.
(7)
				The tube housing assembly supports shall be adjusted such that the tube housing
				assembly will remain stable during an exposure unless the tube housing movement
				is a design function of the x-ray system.
(8) The location of the focal spot may be
				indicated on a readily visible area of the x-ray source housing in the plane
				parallel to the image receptor when the image receptor is perpendicular to the
				beam axis.
(9) 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) Indication of technique factors shall be
				visible from the operator's position except in the case of spot films made by
				the fluoroscopist.
(C) On equipment
				having fixed technique factors, the recommendation in Part (a)(9)(A) of this
				Rule may be met by permanent markings.