Full calibration measurements on gamma stereotactic radiosurgery units.

CFR · 2024-01-01 · US · Title 10

(a) A licensee authorized to use a gamma stereotactic radiosurgery unit for medical use shall perform full calibration measurements on each unit— (1) Before the first medical use of the unit; (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 sources or following reinstallation of the gamma stereotactic radiosurgery unit in a new location; and (iii) Following any repair of the gamma stereotactic radiosurgery unit that includes removal of the sources or major repair of the components associated with the source assembly; and (3) At intervals not exceeding 1 year, with the exception that relative helmet factors need only be determined before the first medical use of a helmet and following any damage to a helmet. (b) To satisfy the requirement of paragraph (a) of this section, full calibration measurements must include determination of— (1) The output within ±3 percent; (2) Relative helmet factors; (3) Isocenter coincidence; (4) Timer accuracy and linearity over the range of use; (5) On-off error; (6) Trunnion centricity; (7) Treatment table retraction mechanism, using backup battery power or hydraulic backups with the unit off; (8) Helmet microswitches; (9) Emergency timing circuits; and (10) Stereotactic frames and localizing devices (trunnions). (c

official document · source cfr-2024 · id 10:§ 35.635