32 Ill. Adm. Code 335.8200
Periodic Spot-Checks for Gamma Stereotactic Radiosurgery Units
Section 335.8200
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) Monthly;
2) Before
the first use of the unit on a given day; and
3) After
each source installation.
b) A licensee shall:
1) Perform
the measurements required by subsection (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 subsection (a)(1) of this Section, spot-checks must, at a
minimum:
1) Assure
proper operation of:
A) Treatment
table retraction mechanism, using backup battery power or hydraulic backups
with the unit off;
B) Helmet
microswitches;
C) Emergency
timing circuits; and
D) Stereotactic
frames and localizing devices (trunnions).
2) Determine:
A) The
output for one typical set of operating conditions measured with the dosimetry
system described in Section 335.8080(b) of this Part;
B) The
difference between the measurement made in subsection (c)(2)(A) 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);
C) Source
output against computer calculation;
D) Timer
accuracy and linearity over the range of use;
E) On-off
error; and
F) Trunnion
centricity.
d) To
satisfy the requirements of subsections (a)(2) and (a)(3) of this Section, spot-checks
must assure proper operation of:
1) Electrical
interlocks at each gamma stereotactic radiosurgery room entrance;
2) Source
exposure indicator lights on the gamma stereotactic radiosurgery unit, on the
control console and in the facility;
3) Viewing and intercom
systems;
4) Timer termination;
5) Radiation monitors used
to indicate room exposures; and
6) Emergency off buttons;
e) A
licensee shall arrange for the repair of any system identified in subsection
(c) of this Section that is not operating properly as soon as possible.
f) If
the results of the checks required in subsection (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 spot-check for gamma stereotactic
radiosurgery units required by this Section for 5 years.
1) The record must
include:
A) The
date of the spot-check;
B) The
manufacturer's name, model and serial number for the gamma stereotactic
radiosurgery unit and the instrument used to measure the output of the unit;
C) An
assessment of timer linearity and accuracy;
D) The
calculated on-off error;
E) A determination
of trunnion centricity;
F) The
difference between the anticipated output and the measured output;
G) An
assessment of source output against computer calculations;
H) Notations
indicating the operability of radiation monitors, helmet microswitches,
emergency timing circuits, emergency off buttons, electrical interlocks,
source exposure indicator lights, viewing and intercom systems, timer
termination, treatment table retraction mechanism, and stereotactic frames and
localizing devices (trunnions); and
I) The
name of the individual who performed the periodic spot-check and the signature
of the authorized medical physicist who reviewed the record of the spot-check.
2) A
licensee shall retain a copy of the procedures required by subsection (b) of
this Section until the licensee no longer possesses the gamma stereotactic
radiosurgery unit.