Sec.19-25d-8. Dental radiographic installations

(a) Equipment

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

(2) Diaphragms or cones shall be used for collimating the useful beam and shall provide the same degree of protection as the housing. The diameter of the useful beam at the cone tip shall not be more than three inches (for intra-oral radiography).

(3) A cone or spacer frame shall provide a target-to-skin distance of not less than seven inches with apparatus operating above fifty kvp or four inches with apparatus operating at fifty kvp or below.

(4) (A) For equipment operating up to seventy kvp, the total filtration permanently in the useful beam shall be equivalent to at least one and one-half mm of aluminum. This requirement may be assumed to have been met if the half value layer is not less than one and one-half mm aluminum at normal operating voltages.

(B) For equipment operating above seventy kvp, the total filtration permanently in the useful beam shall be equivalent to at least two and one-half mm of aluminum.

This requirement may be assumed to have been met if the half-value layer is not less than two and one-half mm aluminum at the normal operating voltages.

(5) A device shall be provided to terminate the exposure after a preset time or exposure.

(6) The exposure control switch shall be of the dead-man type.

(7) 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 and well away from the useful beam.

(b) Structural shielding

(1) Dental rooms containing x-ray machines shall be provided with primary barriers at all areas struck by the useful beam. Consideration shall be given to the attentuation provided by the patient.

(2) When dental x-ray units are installed in adjacent rooms or areas, protective barriers shall be provided between the rooms or areas. Note: In many cases structural materials of ordinary walls suffice as a protective barrier without addition of special shielding material.

(c) Operating procedures

(1) Neither the dentist nor his assistant shall be permitted to hold patients or films during exposure, nor shall any individuals be regularly used for this service.

(2) During each exposure, the operator shall stand at least six feet from the patient or behind a protective barrier.

(3) Only the patient shall be in the useful beam.

(4) Neither the tube housing nor the pointer cone shall be hand-held during exposure.

(5) Hand-held fluoroscopes shall not be used in dental examinations.

(Effective October 1, 1982)