Full calibration measurements on teletherapy units.

CFR · 2024-01-01 · US · Title 10

(a) A licensee authorized to use a teletherapy unit for medical use shall perform full calibration measurements on each teletherapy unit— (1) Before the first medical use of the unit; and (2) Before medical use under the following conditions: (i) Whenever spot-check measurements indicate that the output differs by more than 5 percent from the output obtained at the last full calibration corrected mathematically for radioactive decay; (ii) Following replacement of the source or following reinstallation of the teletherapy unit in a new location; (iii) Following any repair of the teletherapy unit that includes removal of the source or major repair of the components associated with the source exposure assembly; and (3) At intervals not exceeding 1 year. (b) To satisfy the requirement of paragraph (a) of this section, full calibration measurements must include determination of— (1) The output within ±3 percent for the range of field sizes and for the distance or range of distances used for medical use; (2) The coincidence of the radiation field and the field indicated by the light beam localizing device; (3) The uniformity of the radiation field and its dependence on the orientation of the useful beam; (4) Timer accuracy and linearity over the range of use; (5) On-off error; and (6) The accuracy of all distance measuring and localization devices in medical use. (c) A licensee shall use the dosimetry system described in § 35.630(a) to measure the output for one set of exposure cond

official document · source cfr-2024 · id 10:§ 35.632