1. (1) The protective tube housing shall be of diagnostic type.
2. (2) Diaphragms or cones shall be used for restricting the useful beam to the area of clinical interest and shall provide at least the same degree of protection as is required of the tube housing.
3. (3) For intra-oral radiography the diameter of the useful beam at the face of the patient shall not exceed three inches.
4. (4) A cone or spacer frame shall provide a source-skin distance of not less than seven inches with equipment operating above 50 kVp or four inches with equipment operating at 50 kVp or below for intra-oral radiography.

5. (5) The aluminum equivalent of the total filtration in the useful beam shall not be less than that shown below:

   Operating kVp	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

6. (6) A device shall be provided to terminate the exposure after a preset time interval or exposure. The exposure switch shall be of the dead-man type, and where protective barriers are required shall be so arranged that it cannot be operated outside the shielded area.
7. (7) Each installation shall be so arranged that the operator can stand at least six feet from the patient, the X-ray tube, and the useful beam during exposure. A protective barrier shall be provided where the operator can not stand at least six feet away from the patient, the X-ray tube and the useful beam during exposures.

8. (8) The tube head shall remain stationary when placed in the exposure position.

   (b) Conditions for operation of equipment.

9. (1) The film shall not be held by the dentist or technician during the exposure.
10. (2) Only the patient shall be in the useful beam.
11. (3) Neither the tube housing, pointer nor cone shall be hand-held during the exposure.
12. (4) Only persons required for the radiographic procedure shall be in the radiographic room during the exposure.
13. (5) For extra-oral radiography, the X-ray film used as the recording medium during the X-ray examination shall show substantial evidence of cut-off (beam delineation).

14. (6) Gonadal shielding of not less than 0.5 mm lead equivalent shall be used for patients who have not passed the reproductive age during radiographic procedures in which the gonads are in the useful beam.

    (c) Special installations.

15. (1) Panoramic installations are dental installations which consist of a tube head with a collimator providing a narrow (1-2mm) useful beam and an extra-oral film carrier which are interlocked in their motion about the patient.

    1. (i) Equipment.

       1. (a) The protective tube housing shall be of diagnostic-type.
       2. (b) Diaphragms or cones shall be used for restricting the useful beam to the area of clinical interest and shall provide the same degree of protection as is required of the tube housing.

       3. (c) The aluminum equivalent of the total filtration in the useful beam shall not be less than that shown below:

          Operating kVp	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

       4. (d) A device shall be provided to terminate the exposure after a preset time interval or exposure. The exposure switch shall be of the dead-man type.
       5. (e) Each installation shall be provided with a protective barrier for the operator or shall be so arranged that the operator can stand at least six feet from the patient, the X-ray tube, and the useful beam.
    2. (ii) Conditions for operation of equipment. Only the patient shall be in the useful beam.

(a) Equipment.