Code of Massachusetts Regulations
105 CMR - DEPARTMENT OF PUBLIC HEALTH
Title 105 CMR 120.000 - The Control of Radiation
RECORDKEEPING REQUIREMENTS
Section 120.404 - General Requirements for All Diagnostic X-ray Systems

Universal Citation: 105 CMR 120.000 MA Code of Regs 120.404

Current through Register 1531, September 27, 2024

In addition to other requirements of 105 CMR 120.400, all diagnostic x-ray systems shall meet the following requirements:

(A) 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."

(B) Battery Charge Indicator. On battery-powered x-ray 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.

(C) 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 100 milliroentgen (25.8 /C/kg) 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.

(D) Radiation from Components Other Than the Diagnostic Source Assembly. The radiation emitted by a component other than the diagnostic source assembly shall not exceed two milliroentgen (0.516 /C/kg) 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.

(E) Beam Quality.

(1) Half-value Layer.
(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 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.

(b) For capacitor energy storage equipment, compliance with the requirements of 105 CMR 120.404(E) shall be determined with the system fully charged and a setting of ten mAs for each exposure.

(c) The required minimal aluminum equivalent filtration shall include the filtration contributed by all materials which are always present between the source and the patient.

(2) Filtration Controls. For x-ray systems which have variable kVp and variable filtration for the useful beam, a device shall link the kVp selector with the filter(s) and shall prevent an exposure unless the minimum amount of filtration required by 105 CMR 120.404(E)(1) is in the useful beam for the given kVp which has been selected.

Specified Dental Systems \1\

TABLE I

X-Ray Tube Voltage (kilovolt peak)

Design Operating Range

Measured Operating Potential

Minimum HVL (mm in Aluminum)

Specified Dental Systems1

Other

X-Ray Systems2

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 105 CMR 120.404 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 105 CMR 120.404 and manufactured on or after June 10, 2006.

(F) Multiple Tubes. Where 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. This indication shall be both on the x-ray control panel and at or near the tube housing assembly which has been selected.

(G) Mechanical Support of Tube Housing Assembly. The tube housing assembly supports shall be adjusted such that the tube housing assembly will remain stable during an exposure unless tube housing movement is a designed function of the x-ray system.

(H) Technique Indicators.

(1) The technique factors to be used during an exposure shall be indicated before the exposure begins. If automatic Exposure controls are used, the technique factors which are set prior to the exposure shall be indicated.

(2) The requirement of 105 CMR 120.404(H)(1) may be met by permanent markings on equipment having fixed technique factors. Indication of technique factors shall be visible from the operator's position except in the case of spot films made by the fluoroscopist.

(I) Maintaining Compliance Diagnostic x-ray systems and their associated components used on humans and certified pursuant to the Federal X-Ray Equipment Performance Standard ( 21 CFR Part 1020) shall be maintained in compliance with applicable requirements of that standard.

(J) Locks. All positioning locking, holding, and centering devices on x-ray systems components and systems shall function as intended.

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