35.645—Periodic spot-checks for gamma stereotactic radiosurgery units.
(a)
A licensee authorized to use a gamma stereotactic radiosurgery unit for medical use shall perform spot-checks of each gamma stereotactic radiosurgery facility and on each unit—
(1)
Perform the measurements required by paragraph (a) of this section in accordance with written procedures established by the authorized medical physicist. That individual need not actually perform the spot check measurements.
(2)
Have the authorized medical physicist review the results of each spot-check within 15 days. The authorized medical physicist shall notify the licensee as soon as possible in writing of the results of each spot-check.
(c)
To satisfy the requirements of paragraph (a)(1) of this section, spot-checks must, at a minimum—
(i)
Treatment table retraction mechanism, using backup battery power or hydraulic backups with the unit off;
(i)
The output for one typical set of operating conditions measured with the dosimetry system described in § 35.630(b) ;
(ii)
The difference between the measurement made in paragraph (c)(2)(i) of this section and the anticipated output, expressed as a percentage of the anticipated output (i.e., the value obtained at last full calibration corrected mathematically for physical decay);
(d)
To satisfy the requirements of paragraphs (a)(2) and (a)(3) of this section, spot-checks must assure proper operation of—
(2)
Source exposure indicator lights on the gamma stereotactic radiosurgery unit, on the control console, and in the facility;
(e)
A licensee shall arrange for the repair of any system identified in paragraph (c) of this section that is not operating properly as soon as possible.
(f)
If the results of the checks required in paragraph (d) of this section indicate the malfunction of any system, a licensee shall lock the control console in the off position and not use the unit except as may be necessary to repair, replace, or check the malfunctioning system.
(g)
A licensee shall retain a record of each check required by paragraphs (c) and (d) and a copy of the procedures required by paragraph (b) of this section in accordance with § 35.2645.