NAC459.610. X-ray and electron therapy installations: Surveys; operating procedure; calibration.

     1. All new facilities and existing facilities not previously surveyed must have a survey of radiation protection made by, or under the direction of, a qualified expert. This survey must also be done after any change in the facility or equipment which might cause a significant increase in radiation hazard.

     2. The expert must report his or her findings in writing to the person in charge of the facility, and a copy of the report must be transmitted by the registrant to the Division.

     3. The survey and report must indicate all instances where, in the opinion of the qualified expert, the installation is in violation of any applicable regulation for protection against radiation and must cite the sections violated.

     4. No person other than the patient may be in the treatment room during treatment. When a patient must be held in position for radiation therapy, mechanical supporting or restraining devices must be used.

     5. The output of each therapeutic X-ray machine must be calibrated by a qualified expert, before the machine is first used for medical purposes. Calibrations must be repeated at least once every 12 months and after any change which might significantly increase radiation hazards. Records of calibrations must be provided to and maintained by the registrant. The calibration must include at least the following determinations:

     (a) Verification that the equipment is operating in compliance with the design specifications concerning the light localizer, the side light and backpointer alignment with the isocenter, when applicable, variation in the axis of rotation for the table, gantry and jaw system and beam flatness and symmetry at the specified depths.

     (b) The exposure rate or dose rate for the range and field sizes used and for each effective energy and for each treatment distance used for radiation therapy.

     (c) The effective energy, for example, half-value layer when appropriate, for every combination of kVp and filter used for radiation therapy.

     (d) The congruence between the radiation field and the field indicated by the localizing device when localizing devices are used for radiation therapy.

     (e) The uniformity of the radiation field and its dependence upon the direction of the useful beam.

     (f) The calibration determinations must be provided in sufficient detail so that the absorbed dose in rads to tissue adjacent to, as well as in the useful beam, may be calculated to within ±5 percent of the intended absorbed dose.

     [Bd. of Health, Radiation Control Reg. §§ 6.9.3-6.9.3.3.6, eff. 2-28-80]