N.J. Admin. Code § 7:28-16.3

Current through Register Vol. 56, No. 21, November 4, 2024

Section 7:28-16.3 - Dental radiographic equipment

(a) A person shall not operate or permit the operation of ionizing radiation-producing equipment used in the practice of dentistry unless the equipment meets the requirements listed below:

1. A diagnostic type protective tube housing shall be provided on the x-ray equipment.

2. Diaphragms or cones shall be used to collimate the useful beam and shall provide the same degree of protection as the diagnostic type protective tube housing.

3. For intraoral radiography, the diameter of the useful beam at the end of the cone in contact with the patient shall be no greater than seven centimeters (cm) (2.75 inches) when the source-to-skin distance is 18 cm (seven inches) or more. At SSD's less than 18 cm (seven inches), the diameter of the useful beam at the minimum SSD shall be no greater than six cm (2.36 inches).

4. A cone or spacer frame shall provide a source-to-skin distance of not less than 18 cm (seven inches) when the x-ray unit operates above 50 kVp or not less than 10 cm (four inches) when the x-ray unit operates at or below 50 kVp.

5. All machines purchased, donated, or otherwise obtained after July 1, 1969, shall be equipped with open end cones.

6. The amount of total filtration permanently in the useful beam shall meet the minimum half-value layer (HVL) specified in the following table:

TABLE 1

TABLE OF HALF-VALUE LAYERS FOR DENTAL UNITS

X-ray tube voltage (kilovoltage peak)

Designed operating	Measured	Minimum HVL (mm of A1)
range (kVp)	operating
	potential (kVp)
Below 50	30	1.5
	40	1.5
50 to 70	50	1.5
	60	1.5
	70	1.5
Above 70	71	2.1
	80	2.3
	90	2.5
	100	2.7
	110	3.0
	120	3.2
	130	3.5
	140	3.8
	150	4.1

7. For certified units, the x-ray tube voltage (kilovoltage peak) measured operating potential shall meet the manufacturer's specifications.

8. The exposure control switch shall be of the dead-man type.

9. The exposure control switch shall be provided with a timer that terminates the exposure after a preset time or preset exposure.

10. The exposure control switch button when depressed shall not energize the x-ray tube when the timer is in the "zero" or "off" position.

11. The exposure control switch shall be arranged to allow the operator to stand at least 1.83 meters (six feet) from the patient and well out of the path of the useful beam or to stand behind a protective barrier.

12. The x-ray control panel shall provide visual indication whenever x-rays are produced.

13. For certified units, a signal audible to the operator shall be provided to indicate that the exposure has terminated.

14. For certified units, the coefficient of variation of the timer reproducibility shall not exceed 0.05 measured at any specific combination of technique factors.

15. For uncertified units, the coefficient of variation of the timer reproducibility shall not exceed 0.07 measured at any specific combination of technique factors.

16. For certified units, the timer accuracy shall meet or exceed the manufacturer's specifications. In the absence of manufacturer's specifications, the deviation shall not exceed 10 percent of the indicated value.

17. For certified units, the coefficient of variation of the radiation exposure reproducibility shall not exceed 0.05 measured at any specific combination of technique factors.

18. For uncertified units, the coefficient of variation of the radiation exposure reproducibility shall not exceed 0.07 measured at any combination of technique factors.

19. For uncertified units, the following requirements for radiation exposure linearity shall be met when the equipment is operated on a power supply as specified by the manufacturer for any fixed x-ray tube potential within the range of 40 percent to 100 percent of the maximum rated:

i. For equipment having independent selection of x-ray tube current (mA), the average ratios of exposure to the indicated milliampereseconds product [(C/kg/mAs) or mR/mAs)] obtained at any tube current settings shall not differ by more than 0.10 times their sum. This is: [X[1] - X[2]] 0.10 (X[1] + X[2]) where X[1] and X[2] are the average C/kg/mAs (or mR/mAs) values obtained at any two tube settings.

ii. For equipment having a combined x-ray tube current-exposure time product (mAs) selector, the average ratios of exposure to the indicated milliampereseconds product [(C/kg/mAs) or (mR/mAs)] obtained at any two mAs selector settings shall not differ by more than 0.10 times their sum. This is: [X[1] - X[2]] 0.10 (X[1] + X[2]); where X[1] and X[2] are the average C/kg/mAs (or mR/mAs) values obtained at any two mAs selector settings.

20. For certified units, the requirement for linearity is as follows:

i. For equipment that allows a choice of x-ray tube current settings, the average ratios of exposure to the indicated milliampereseconds product obtained at any two consecutive tube current settings shall not differ by more than 0.10 times their sum: [X[1] -X[2]] 0.10 (X[1] + X[2]); where X[1] and X[2] are the average C/kg/mAs (or mR/mAs) values obtained at each of two consecutive tube current settings or at two tube current settings differing by no more than a factor of two where the tube current selection is continuous.

ii. For equipment having selection of x-ray tube current-exposure time product (mAs), the average ratios of exposure to the indicated milliampereseconds product [C/kg/mAs (or mR/mAs)] obtained at any two consecutive mAs selector settings shall not differ by more than 0.10 times their sum: [X[1] - X[2]] 0.10 (X[1] + X[2]); where X[1] and X[2] are the average C/kg/mAs (or mR/mAs) values obtained at each of two consecutive mAs selector settings or at two mAs settings differing by no more than a factor of two where the mAs selector provides continuous selection.

21. The mechanical support of the tube head and the cone shall maintain the exposure position without movement, unless the diagnostic type protective tube housing movement is a designed function of the x-ray system (for example, as in panoramic units).

N.J. Admin. Code § 7:28-16.3