(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 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 35.642 Periodic H&S (a) A licensee authorized to use for teletherapy units for medical use teletherapy shall perform output spot-checks units on each teletherapy unit once in each calendar month that include determination of- (1) Timer accuracy, and timer linearity over the range of use; (2) On-off error; (3) The coincidence of the radiation and the field
(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 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 35.642 Periodic for teletherapy units H&S (a) A licensee authorized to use teletherapy units for medical use shall perform output spot-checks on each teletherapy unit once in each calendar month that include determination of- (1) Timer accuracy, and timer linearity over the range of use; (2) On-off error; (3) The coincidence of the radiation and the field
2002-2.docx