Mich. Admin. Code R. 333.5373

Current through Vol. 24-24, January 15, 2025

Section R. 333.5373 - X-ray equipment

Rule 373.

(1) The tube housing shall be of the diagnostic type.

(2) The aluminum equivalent of the total filtration in the useful beam shall not be less than that shown in table 373-1.

TABLE 373-1

Operating Potential	Minimum Total Filter (Inherent plus added)
Below 50 kVp	0.5 mm aluminum
50 - 70 kVp	1.5 mm aluminum
Above 70 kVp	2.5 mm aluminum

(3) If the filter in the machine is not accessible for examination and the total filtration is not known, subrule (2) of this rule may be assumed to have been met if the half-value layer is not less than any of the following:

(a) 0.6 mm aluminum at 49 kVp.

(b) 1.6 mm aluminum at 70 kVp.

(c) 2.6 mm aluminum at 90 kVp.

(4) Under conditions of subrule (3) of this rule, for tube potentials above 90 kVp, subrule (2) of this rule may be assumed to have been met if the half-value layer is not less than that specified in table 373-2.

(5) 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 373-2.

TABLE 373-2

Design Operating Range (kVp)	Measured Potential (kVp)	Half-value Layer (mm aluminum)
Below 50	30	0.3
	40	0.4
	49	0.5
50 to 70	50	1.2
	60	1.3
	70	1.5
Above 70	80	2.3
	90	2.5
	100	2.7
	110	3.0
	120	3.2
	130	3.5
	140	3.8
	150	4.1

(6) To determine the half-value layer at an x-ray tube potential which is not listed in table 373-2, linear interpolation or extrapolation may be made. Positive means shall be provided to ensure that at least the minimum filtration needed to achieve these beam quality requirements is in the useful beam during each exposure.

(7) Radiographic equipment designed for use with an intraoral image receptor shall be provided with means to limit the x-ray beam to either of the following:

(a) If the minimum source-skin distance is 18 centimeters or more, the x-ray field at the minimum source-skin shall be containable in a circle having a diameter of not more than 7 centimeters.

(b) If the minimum source-skin is less than 18 centimeters, the x-ray field at the minimum SSD shall be containable in a circle having a diameter of not more than 6 centimeters.

(8) For intraoral exposures, means shall be provided to limit the source-skin distance to not less than 18 centimeters with apparatus operable above 50 kVp, and not less than 10 centimeters with apparatus not operable above 50 kVp. Open-ended cones are recommended to reduce scattered radiation.

(9) Mechanical support of the tube head and pointer cone shall maintain the exposure position without drift or vibration of sufficient magnitude to cause the need for manually restraining the tube or retaking the x-ray.

(10) A device shall be provided that terminates the exposure at a preset time interval or exposure limit. The operator shall be able to terminate the exposure at any time by discontinuing pressure upon the exposure switch except that during serial radiography means may be provided to permit completion of a single exposure of the series in progress.

(11) If a recycling timer is employed, it shall not be possible to make a repeat exposure without release of the exposure switch to reset the timer.

(12) The exposure control switch shall have a circuit-closing contact which can be maintained only by continuous pressure on the switch by the operator.

(13) Unless protective shielding is provided for the operator, the length of the exposure control switch cord or remote control location shall be such that the operator shall be able to stand at least 1.8 meters (6 feet) away from the patient and the x-ray tube and out of the useful beam.

(14) The control panel shall provide positive visual identification of the production of x-rays when the x-ray tube is energized. A milliammeter may meet the requirements of this subrule.

(15) A signal audible to the operator shall indicate that the exposure has ended.

(16) 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 before the exposure shall be indicated. On equipment having fixed technique factors, this requirement may be met by permanent markings. Indication of technique factors shall be visible from the operator's position.

Mich. Admin. Code R. 333.5373

2016 MR 10, Eff. 5/25/2016