1. (1) Equipment.

   1. (i) The protective tube housing shall be of diagnostic type.
   2. (ii) Collimating devices capable of restricting the useful beam to the area of clinical interest shall be used and shall provide the same degree of protection as is required of the tube housing.
   3. (iii) The X-ray films used as the recording medium during the X-ray examination shall show substantial evidence of cut-off (beam delineation).

   4. (iv) 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

   5. (v) A device shall be provided which terminates the exposure after a preset time interval or exposure. The exposure switch shall be of the dead-man type and shall be so arranged that it cannot be operated outside a shielded area.

2. (2) Structural shielding.

   1. (i) Control apparatus for the radiographic equipment shall be located in in an adjacent room or in a fixed booth within the same room provided such booth is composed of radiation shielding to a minimum height of seven feet. The control booth either shall be so arranged that the radiation has to be scattered at least twice before entering the booth, or shall be provided with a protective door that is interlocked in such a way that the X-ray tube(s) cannot be energized unless the door is in the closed position.
   2. (ii) The operator shall be able to see the animal patient by means of a mirror or through a window of lead equivalent sufficient for the required protection and so placed that the operator is always in a shielded position.

3. (3) Conditions for operation of equipment.

   1. (i) Only persons required for the X-ray procedure shall be in the X-ray room during the exposures.

   2. (ii) When an animal patient must be held in position during exposures, mechanical supporting or restraining devices shall be used. Animal patients or films shall be held only under extreme conditions when clinically necessary. Individuals holding animal patients or films shall wear protective gloves having at least 0.5 mm lead equivalent, a protective apron of at least 0.25 mm lead equivalent, and shall keep all parts of his/her body out of the useful beam. The exposure of any individual used for holding animals shall be monitored. Pregnant women and persons under 18 years of age shall not hold animal patients or films under any conditions.

      (b) Portable or mobile radiographic installations.

4. (1) Equipment.

   1. (i) The protective tube housing shall be of diagnostic type.
   2. (ii) Collimating devices capable of restricting the useful beam to the area of clinical interest shall be used and shall provide the same degree of protection as is required of the tube housing.
   3. (iii) The X-ray film used as the recording medium during the X-ray examination shall show evidence of cut-off (beam delineation).

   4. (iv) 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

   5. (v) A device shall be provided which terminates the exposure after a preset time interval or exposure.
   6. (vi) A dead-man type of exposure switch shall be provided with a cord sufficiently long so that the operator can stand at least six feet from the animal patient, the X-ray tube, and the useful beam.

5. (2) Conditions for operation of equipment.

   1. (i) No person shall be regularly employed to support or hold animals or film during X-ray exposures.

   2. (ii) When an animal must be held in position during exposures, mechanical supporting or restraining devices shall be used. Individuals should hold animals only when clinically necessary under extreme conditions. Such individuals shall wear protective gloves having at least 0.5 mm lead equivalent, a protective apron of at least 0.25 mm lead equivalent, and shall keep all parts of his body out of the useful beam. The exposure of any individual used for holding animals shall be monitored. Fertile women and individuals under 18 years of age shall not hold animals under any conditions.

      (c) Fluoroscopic installations.

6. (1) Equipment.

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

   2. (ii) Equipment shall be so constructed that the entire cross section of the useful beam is always intercepted by a primary protective barrier (usually a lead glass screen or image intensifier assembly) irrespective of the panel screen distance. For conventional fluoroscopes, this requirement may be assumed to have been met if, when the collimating system is opened to its fullest extent, an unilluminated margin is left on all edges of the fluorescent screen regardless of the position of the screen during use.

      1. (a) Collimaters, and adjustable diaphragms, or shutters used to restrict the size of the useful beam shall provide the same degree of protection as is required of the tube housing.
      2. (b) The exposure shall automatically terminate when the barrier is removed from the useful beam.
      3. (c) With the fluorescent screen 14 inches from the panel of the tabletop, the exposure rate two inches beyond the viewing surface of the screen shall not exceed 30 mR/hr for each roentgen per minute at the tabletop with the screen in the useful beam without a patient and with the fluoroscope operating at the highest potential employed.

   3. (iii) 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. (iv) The fluoroscopic exposure switch shall be of the dead-man type.

   5. (v) Mobile fluoroscopic equipment is subject to the following additional requirements:

      1. (a) in the absence of a tabletop, a cone or spacer frame shall limit the source-to-skin distance to not less than 12 inches;
      2. (b) image intensification shall always be provided;
      3. (c) it shall be impossible to operate a machine unless the useful beam is intercepted by the image intensifier.

7. (2) Conditions for operation of equipment.

   1. (i) Protective gloves and aprons of at least 0.25 mm lead equivalent each shall be made available and shall be worn by the fluoroscopist during every examination.
   2. (ii) Unless measurements indicate that they are not needed protective gloves and protective aprons of at least 0.25 mm lead equivalent each shall be worn by the physician, nurse, technician and all other persons within the fluoroscopic room.
   3. (iii) Only persons needed in the fluoroscopic room shall be present during the exposure.
   4. (iv) The fluoroscopic room shall be free of extraneous light that interferes with the examination.

(a) Fixed radiographic installations.