S.C. Code Regs. § § 61-64.IV.RHB 4.5

Current through Register Vol. 48, No. 10, October 25, 2024

Section 61-64.IV.RHB 4.5 - Intraoral Dental Radiographic Systems

In addition to the applicable provisions of this regulation, the requirements of this Part apply to all stationary, transportable, mobile, portable, and hand-held dental systems.

4.5.1 Source-to-Skin Distance (SSD). X-ray systems designed for use with an intraoral image receptor shall be provided with means to limit the source-to-skin distance, to not less than eighteen centimeters (18 cm).

4.5.2 Field Limitation. Radiographic systems designed for use with an intraoral image receptor shall be provided with means to limit the x-ray field such that:

4.5.2.1 The x-ray field at the minimum SSD shall be containable in a circle having a diameter of no more than seven centimeters (7 cm).

4.5.2.2 An open-ended Position Indication Device (PID) shall be used, and shall provide the same degree of protection as the housing. Pointed PIDs shall not be used.

4.5.2.3 The operator shall position the end of the PID as close as practicable to the skin of the patient.

4.5.3 Timers. Means shall be provided to terminate the exposure at a preset time interval, preset product of current and time, a preset number of pulses, or a preset radiation exposure to the image receptor. In addition:

4.5.3.1 It shall not be possible to make an exposure when the timer is set to a "zero (0)" or "off position if either position is provided.

4.5.3.2 Termination of an exposure shall cause automatic resetting of the timer to its initial setting or to "zero (0)."

4.5.3.3 Timer reproducibility. The average exposure period (T) shall be greater than or equal to five (5) times the maximum exposure period (Tmax) minus the minimum exposure period (Tmin) when four (4) timer tests are performed: T >= 5 (Tmax - Tmin).

4.5.4 X-ray Control.

4.5.4.1 An x-ray control shall be incorporated into each x-ray system such that an exposure can be terminated by the operator at any time, except for exposures of one-half second (0.5 s) or less.

4.5.4.2 Each x-ray control shall be located in such a way as to meet the following requirements:

4.5.4.2.1 Stationary and transportable x-ray systems installed after July 1, 1993, shall have the x-ray control permanently mounted in a protected area, so that the operator is required to remain in that protected area during the entire exposure; and

4.5.4.2.2 For stationary and transportable x-ray systems without a protected area and installed before July 1, 1993, the exposure switch shall be such that the operator shall stand at least six feet (6 ft) away from the tube housing and out of the direct beam.

4.5.4.2.3 For mobile and portable x-ray systems, the exposure switch shall meet the requirements of 4.5.4.2.2.

4.5.4.2.4 Visual and/or audible indication, observable at or from the operator's protected position, shall be provided whenever x-rays are initiated and terminated.

4.5.5 Exposure Reproducibility. The coefficient of variation shall not exceed 0.05 when all selectable technique factors are held constant. This requirement shall be deemed to have been met if, when four (4) exposures are made at identical technique factors, the value of the average exposure (E) is greater than or equal to five (5) times the maximum exposure (Emax) minus the minimum exposure (Emin): E >= 5 (Emax - Emin).

4.5.6 Linearity. When the equipment allows a choice of x-ray tube current settings and is operated on a power supply as specified by the manufacturer for any fixed x-ray tube potential within the maximum rating, the average ratios of exposure to the indicated milliAmpere-seconds product obtained at any two (2) tube current settings shall not differ by more than 0.10 times their sum: [X1 - X2] < 0.10 (X1 + X2) where X1 and X2 are the average mR/mAs values obtained at each of the two (2) tube current settings.

4.5.7 Accuracy. Deviation of technique factors from indicated values shall not exceed the limits specified for that system by the manufacturer. In the absence of manufacturer's specifications, the deviation shall not exceed ten percent (10%) of the indicated value.

4.5.8 kVp limitations. Dental x-ray machines with a nominal fixed kVp of less than fifty kilovoltage peak (50 kVp) shall not be used to make diagnostic dental radiographs of humans.

4.5.9 Multiple Tubes. Where two (2) or more radiographic tubes are controlled by one (1) 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 and at or near the tube housing which has been selected.

4.5.10 Mechanical Support of Tube Head. The tube housing assembly supports shall be adjusted so that the tube housing assembly will remain stable during an exposure unless the tube housing movement is a designed function of the x-ray system.

4.5.11 Structural Shielding.

4.5.11.1 Dental rooms containing x-ray machines shall be provided with primary and secondary barriers for all areas struck by the useful beam, as required by RHB 4.4.4.2.

4.5.11.2 When dental x-ray units are installed in adjacent rooms or areas, protective barriers shall be provided between the rooms or areas.

4.5.11.3 Pass throughs between adjacent areas shall be securely interlocked in a functional, permanent manner.

4.5.11.4 Shielding plans are not required for intraoral dental radiographic installations.

4.5.12 Operating Procedures.

4.5.12.1 Neither the dentist nor his or her assistant shall hold patients or films during exposure, nor shall any individual be regularly used for this service.

4.5.12.2 The tube housing and the PID shall not be hand-held during an exposure.

4.5.12.3 Dental fluoroscopy without image intensification shall not be used.

4.5.12.4 Thyroid shielding shall be utilized for patients when it will not interfere with examination.

4.5.12.5 Only persons required for the radiographic procedure shall be in the radiographic room during exposures.

4.5.13 Hand-Held X-ray System - Intraoral Equipment

4.5.13.1 Any hand-held x-ray systems for intraoral use shall be equipped with a non-removable backscatter shield of not less than 0.25 millimeter lead equivalent and 15.2 centimeters (6 inches) in diameter that is positioned as close as practicable to the distal end of the position indicating device.

4.5.13.2 The facility shall maintain documentation that each operator has completed training as specified by the manufacturer.

4.5.13.3 The facility shall adopt and follow protocols provided by the manufacturer and approved by the Department regarding the safe operation of the device.

4.5.13.4 When operating a hand-held x-ray system for intraoral use, operators shall wear a 0.25 millimeter lead equivalent apron.

4.5.13.5 If the operator has difficulty in holding the hand-held x-ray system stationary during the exposure, the operator shall use a stand to immobilize.

4.5.13.6 The registrant shall secure the hand-held x-ray system from unauthorized removal or use.

S.C. Code Regs. § 61-64.IV.RHB 4.5

Replaced and amended by State Register Volume 40, Issue No. 06, eff. 6/24/2016; State Register Volume 47, Issue No. 05, eff. 5/26/2023.