(1) A licensee
authorized to use a gamma stereotactic radiosurgery unit for medical use shall
perform full calibration measurements on each gamma stereotactic radiosurgery:
(a) Before the first medical use of the
unit;
(b)
1. Before medical use 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;
2. Before
medical use following replacement of the source or following reinstallation of
the gamma stereotactic radiosurgery unit in a new location;
3. 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
(c) 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.
(2) Full
calibration measurements of the gamma stereotactic radiosurgery unit shall
include the determination of:
(a) The output
within 3 percent;
(b) Relative
helmet factors;
(c) Isocenter
coincidence;
(d) Timer constancy
and linearity over the range of use;
(e) On-off errors;
(f) Trunnion centricity;
(g) Treatment table retraction mechanism,
using backup battery power or hydraulic backups with the unit off;
(h) Helmet microswitches;
(i) Emergency timing circuits; and
(j) Stereotactic frames and localizing
devices (trunnions).
(3)
A licensee shall use the dosimetry system described in Rule
64E-5.640, F.A.C., to measure
the output for one set of exposure conditions. The remaining radiation
measurements required in paragraph
64E-5.6412(2)(a),
F.A.C., may be made using a dosimetry system that indicates relative dose
rates.
(4) A licensee shall make
full calibration measurements required by subsection
64E-5.6412(1),
F.A.C., in accordance with published protocols accepted by nationally
recognized bodies.
(5) A licensee
shall correct mathematically the outputs determined in paragraph
64E-5.6412(2)(a),
F.A.C., at intervals not exceeding 1 month for cobalt-60 and at intervals
consistent with 1 percent physical decay for all other radionuclides.
(6) Full calibration measurements required by
subsection
64E-5.6412(1),
F.A.C., and physical decay corrections required by subsection
64E-5.6412(5),
F.A.C., shall be performed by the authorized medical physicist.
(7) A licensee shall maintain a record of
each gamma stereotactic radiosurgery unit calibration for three years. The
record shall include:
(a) The date of the
calibration;
(b) The manufacturer's
name, model number, and serial number for both the gamma stereotactic
radiosurgery unit and the source;
(c) The model numbers and serial numbers of
the instruments used to calibrate the gamma stereotactic radiosurgery
unit;
(d) The results and an
assessment of the full calibrations; and
(e) The signature of the authorized medical
physicist.