La. Admin. Code tit. 33 § XV-607

Current through Register Vol. 50, No. 11, November 20, 2024

Section XV-607 - Dental Radiographic Systems

A. In addition to the provisions of LAC 33:XV.603 and 604, the requirements of this Section apply to dental radiographic facilities using intraoral, panoramic, and cephalometric systems. Dental facilities using cone beam computed tomography (CBCT) technology shall follow applicable provisions of LAC 33:XV.610.G.

1. Warning Label

a. On systems manufactured on or before June 10, 2006, the control panel containing the main power switch shall bear the warning statement, or the warning statement in LAC 33:XV.607.A.1.b, 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. On systems manufactured after June 10, 2006, 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, operating instructions, and maintenance schedules are observed."

2. Field Limitation. The following requirements shall be met:

a. radiographic systems designed for use with an intraoral image receptor shall be provided with means to limit the X-ray field such that the X-ray field at the minimum SSD shall be containable in a circle having a diameter of no more than 7 centimeters;

b. a shielded PID (position-indicating device) shall be used. The shielding shall be equivalent to the requirements of LAC 33:XV.604.A.3; and

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

3. Radiation Exposure Control for Certified Systems. The following requirements shall be met.

a. Exposure Initiation

i. Means shall be provided to initiate the radiation exposure by a positive action on the part of the operator, such as the depression of a switch. Radiation exposure shall not be initiated without such a positive action; and

ii. it shall not be possible to make an exposure when the timer is set to a "zero" or "off" position if either position is provided.

b. Exposure Termination

i. Means shall be provided to terminate the exposure at a preset time interval, a preset product of current and time, a preset number of pulses, or a preset radiation exposure to the image receptor;

ii. 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 1/2 second or less; and

iii. termination of an exposure shall cause automatic resetting of the timer to its initial setting or to "zero."

c. Exposure Indication. The X-ray control shall provide visual indication observable at or from the operator's protected position whenever X-rays are produced. In addition, a signal audible to the operator shall indicate that the exposure has terminated.

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d. Exposure Duration (Timer) Reproducibility. With a timer setting of 0.5 seconds or less, the difference between the maximum exposure time (T_max) and the minimum exposure time (T_min) shall be less than or equal to 10 percent of the average time (T), when 10 timing tests are performed:

e. Exposure Control Location and Operator Protection. Each X-ray control shall be located in such a way as to meet the following requirements. Except for units designed to be hand-held, the exposure control shall allow the operator to be:

i. behind a protective barrier at least 6.5 feet (2.0 m) high; or

ii. at least 12 feet (3.7 m) from the tube housing assembly while making exposures; and

iii. the operator's protected area shall provide means to view the patient during the X-ray procedure.

f. Administrative controls include the following.

i. For human use:

(a). patient and film holding devices shall be used when the techniques permit;

(b). except for units designed to be hand-held, the tube housing and the PID shall not be hand-held during an exposure;

(c). the X-ray system shall be operated in such a manner that the useful beam at the patient's skin does not exceed the requirements of LAC 33:XV.607.A.2.a; and

(d). dental fluoroscopy without image intensification shall not be used.

ii. For Nonhuman Use

(a). Except for units designed to be hand-held, the tube housing and the PID shall not be hand-held during the exposure.

(b). The X-ray system shall be operated in such a manner that the useful beam at the patient's skin does not exceed the requirements of LAC 33:XV.607.A.2.a.

(c). Dental fluoroscopy without image intensification shall not be used.

(d). An operator shall wear a 0.25 lead equivalent apron during an exposure or a personal dosimetry badge.

(e). Unless required to restrain an animal, the operator shall stand at least six feet away from the useful beam and the animal during radiographic exposures.

(f). No individual, other than the operator, shall be in the X-ray room or area while exposures are being made unless such individual's assistance is required.

(g). When an animal must be held in position during radiography, mechanical supporting or restraining devices shall be used when technique permits.

4. Exposure Reproducibility. The coefficient of variation shall not exceed 0.05 when all technique factors are held constant. This requirement shall be deemed to have been met if, when 10 exposures are made within a period of one hour at identical technique factors, the difference between the maximum exposure value (E_max) and the minimum exposure value (E_min) shall be less than or equal to 10 percent of the average exposure (E):

5. 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 range of 40 to 100 percent of the maximum rating, the average ratios of exposure to the indicated milliampere-seconds product obtained at any two consecutive tube current settings shall not differ by more than 0.10 times their sum:

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X₁ and X₂ are the average mR/mAs values obtained at each of two consecutive tube current settings.

6. Accuracy. Deviation of technique factors from indicated values shall not exceed the limits specified for that system by its manufacturer. In the absence of manufacturer's specification the deviation shall not exceed 10 percent of the indicated value.

7. kVp Limitations. Dental X-ray machines with a nominal fixed kVp of less than 50 kVp shall not be used to make diagnostic dental radiographs of humans.

8. Source-to-Skin Distance. X-ray systems designed for use with an intraoral image receptor shall be provided with means to limit source-to-skin distance to not less than 18 centimeters.

9. Hand-Held Intraoral Equipment. In addition to the standards in this Chapter, the following applies specifically to hand-held devices.

a. The hand-held X-ray system shall be equipped with a backscatter shield of not less than 0.25 mm lead equivalent and 15.2 cm (6 inches) in diameter that is positioned as close as practicable to the distal end of the position indication device.

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

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

d. If the operator has difficulty in holding the device stationary during the exposure, the operator shall use a stand to immobilize the device.

e. The registrant shall secure the hand-held device from unauthorized removal or use.

10. Multiple Tubes. Where two or more radiographic tubes are controlled by one exposure switch, the tube which has been selected shall be clearly indicated prior to initiation of the exposure. Only the selected tube can be energized. This indication shall be both on the X-ray control panel and at or near the tube housing assembly which has been selected.

11. Mechanical Support of Tube Head. 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.

12. Battery Charge Indicator. 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.

13. Locks. All position locking, holding, and centering devices on the X-ray system components and systems shall function as intended.

B. Additional Requirements for Extraoral, Panoramic, and Cephalometric Units.

1. X-ray systems designed for use with extraoral image receptors and when used with an extraoral image receptor, shall be provided with means to limit the X-ray field in the plane of the image receptor so that such field does not exceed each dimension of the image receptor by more than 2 percent of the SID, when the axis of the X-ray beam is perpendicular to the plane of the image receptor. In addition, means shall be provided to align the center of the X-ray field with the center of the image receptor to within 2 percent of the SID, or means shall be provided to both size and alignment of the X-ray field such that the X-ray field at the plane of the image receptor does not extend beyond any edge of the image receptor. These requirements may be met with:

a. an assortment of removable, fixed-aperture, beam-limiting devices sufficient to meet the requirement for each combination of image receptor size and SID for which the unit is designed. Each such device shall have clear and permanent markings to indicate the image receptor size and SID for which it is designed; or

b. a beam-limiting device having multiple fixed apertures sufficient to meet the requirements for each combination of image receptor size and SID for which the unit is designed. Permanent, clearly legible markings shall indicate the image receptor size and SID for which each aperture is designed and shall indicate which aperture is in position for use.

La. Admin. Code tit. 33, § XV-607

Promulgated by the Department of Environmental Quality, Nuclear Energy Division, LR 13:569 (October 1987), amended by the Office of Air Quality and Radiation Protection, Radiation Protection Division, LR 19:1421 (November 1993), amended by the Office of the Secretary, Legal Affairs Division, LR 33:449 (March 2007), Amended by the Office of the Secretary, Legal Affairs and Criminal Investigations Division, LR 482942 (12/1/2022).

AUTHORITY NOTE: Promulgated in accordance with R.S. 30:2001 et seq. and 2104.B.