| (III) - (V) of this clause below.
(II) The calibration shall be performed by a licensed
medical physicist with a specialty in therapeutic radiological physics
who is physically present at the facility during the calibration.
(III) Calibration radiation measurements required by
subclause (I) of this clause shall be performed using a dosimetry
system:
(-a-) having a calibration factor for cobalt-60 gamma
rays traceable to a national standard;
(-b-) that is traceable to a national standard and
at an interval not to exceed 24 months;
(-c-) that has been calibrated in such a fashion that
an uncertainty can be stated for the radiation quantities monitored
by the system; and
(-d-) that has had constancy checks performed on the
system as specified by the licensed medical physicist with a specialty
in therapeutic radiological physics.
(IV) Calibrations shall be in sufficient detail that
the dose at a reference point in a tissue equivalent phantom can be
calculated to within an uncertainty of 5.0%.
(V) The calibration of the therapy unit shall include,
but not be limited to, the following determinations.
(-a-) Verification that the equipment is operating
in compliance with the design specifications concerning the light
field, patient positioning lasers, and back-pointer lights with the
isocenter when applicable, variation in the axis of rotation for the
table, gantry, and collimator system, and beam flatness and symmetry
at the specified depth.
(-b-) The absorbed dose rate at various depths in a
tissue equivalent phantom for the range of field sizes used, for each
effective energy, that will verify the accuracy of the dosimetry of
all therapy procedures utilized with that therapy beam.
(-c-) The uniformity of the radiation field to include
symmetry, flatness, and dependence on gantry angle.
(-d-) Verification that existing isodose charts applicable
to the specific machine continue to be valid or are updated to existing
machine conditions.
(-e-) Verification of transmission factors for all
accessories such as wedges, block trays, and/or universal and custom
made beam modifying devices.
(VI) Calibration of therapeutic systems containing
asymmetric jaws, multileaf collimation, or dynamic/virtual wedges
shall be performed with an established protocol. The procedures shall
be developed by a licensed medical physicist with a specialty in therapeutic
radiological physics and shall be in writing or documented in an electronic
reporting system. Current recommendations by a national professional
association as the American Association of Physicists in Medicine,
Task Group 142 report: "Quality Assurance of Medical Accelerators"
published August 17, 2009, would be considered an established protocol.
(VII) Records of calibration measurements specified
in subclause (I) of this clause and dosimetry system calibrations
specified in subclause (III) of this clause shall be maintained by
the registrant in accordance with subsection (l) of this section for
inspection by the agency.
(VIII) A copy of the latest calibrated absorbed dose
rate measured in accordance with subclause (I) of this clause shall
be available at a designated area within the facility housing that
radiation therapy system.
(iii) Spot checks shall be performed on systems subject
to this paragraph during calibrations and thereafter at weekly intervals
with the period between spot checks not to exceed 5 treatment days.
Such radiation output measurements shall meet the following requirements.
(I) The spot check procedures shall be performed in
accordance with established protocol, shall be in writing, or documented
in an electronic reporting system, and shall have been developed by
a licensed medical physicist with a specialty in therapeutic radiological
physics. Either the spot check protocol entitled, "Comprehensive QA
for Radiation Oncology," Task Group 40, Radiation Therapy Committee,
American Association of Physicists in Medicine, Medical Physics 21(4):
581-618, April, 1994, or Task Group 142 report: Quality Assurance
of Medical Accelerators, published by American Association of Physicists
in Medicine on August 17, 2009, are accepted as an established protocol.
At a minimum, the spot check protocol shall include items in subclauses
(III) - (VI) of this clause.
(II) If a licensed medical physicist does not perform
the spot check measurements, the results of the spot check measurements
shall be reviewed by a licensed medical physicist at a frequency not
to exceed 5 treatment days and a record kept of the review. If the
output varies by more than 3.0% from the expected value, a licensed
medical physicist shall be notified immediately.
(III) The written spot check procedures shall specify
the frequency at which tests or measurements are to be performed and
the acceptable tolerance for each parameter measured in the spot check
when compared to the value for that parameter determined in the calibration.
(IV) Where a system has built-in devices that provide
a measurement of any parameter during irradiation, such measurement
shall not be utilized as a spot check measurement.
(V) A parameter exceeding a tolerance set by a licensed
medical physicist shall be corrected before the system is used for
patient irradiation.
(VI) Whenever a spot check indicates a significant
change in the operating characteristics of a system, as specified
in a licensed medical physicist's written procedures, the system shall
be recalibrated, as required in this clause of this subparagraph.
(VII) Records of spot check measurements and any necessary
corrective actions shall be maintained by the registrant in accordance
with subsection (l) of this section for inspection by the agency.
(VIII) Spot checks shall be obtained using a system
satisfying the requirements of clause (ii)(III) of this subparagraph.
(iv) Facilities with therapeutic radiation machines
with energies of 1 MeV and above shall procure the services of a licensed
medical physicist with a specialty in therapeutic radiological physics.
(I) The physicist shall be responsible for:
(-a-) calibration of radiation machines;
(-b-) supervision and review of beam and clinical dosimetry;
(-c-) measurement, analysis, and tabulation of beam
data;
(-d-) establishment of quality assurance procedures
and performance of spot check review; and
(-e-) review of absorbed doses delivered to patients.
(II) The licensed medical physicist described in subclause
(I) of this clause shall also be available and responsive to immediate
problems or emergencies.
(4) Radiation therapy simulators.
(A) General requirements. In addition to the general
requirements in paragraph (1)(B), (C), (F), and (H) of this subsection,
radiation therapy simulators shall comply with the following:
(i) Technique chart. A technique chart relevant to
the particular radiation machine shall be provided or electronically
displayed in the vicinity of the console and used by all operators.
(ii) Operating and safety procedures. Each registrant
shall have and implement written operating and safety procedures in
accordance with paragraph (1)(G) of this subsection.
(iii) Protective devices. When utilized, protective
devices shall meet the following requirements.
(I) Protective devices shall be made of no less than
0.25 mm lead equivalent material.
(II) Protective devices, including aprons, gloves,
and shields shall be checked annually for defects, such as holes,
cracks, and tears. These checks may be performed by the registrant
by visual, tactile, or x-ray imaging. If a defect is found, equipment
shall be replaced or removed from service until repaired. A record
of this test shall be made and maintained by the registrant in accordance
with subsection (l) of this section for inspection by the agency.
(iv) Viewing system. Windows, mirrors, closed circuit
television, or an equivalent system shall be provided to permit the
operator to continuously observe the patient during irradiation. The
operator shall be able to maintain verbal, visual, and aural contact
with the patient.
(v) Operator position. The operator's position during
the exposure shall be such that the operator's exposure is as low
as reasonably achievable (ALARA) and the operator is a minimum of
6 feet from the source of radiation or protected by an apron, gloves,
or other shielding having a minimum of 0.25 mm lead equivalent material.
(vi) Holding of tube. In no case shall an individual
hold the tube or tube housing assembly supports during any radiographic
exposure.
(vii) No individuals other than the patient and the
operator(s) shall be in the treatment room during operation of the
simulator.
Cont'd... |
