A licensee authorized to use a remote afterloader unit for medical use must perform full calibration measurements on each unit:
before the first medical use of the unit;
before medical use under the following conditions:
following replacement of the source or following reinstallation of the unit in a new location outside the facility; and
following any repair of the unit that includes removal of the source or major repair of the components associated with the source exposure assembly;
at intervals not exceeding one quarter for high dose-rate, medium dose-rate, and pulsed dose-rate remote afterloader units with sources whose half-life exceeds 75 days; and
at intervals not exceeding one year for low dose-rate remote afterloader units.
To satisfy subpart 1, full calibration measurements must include, as applicable, determination of:
the output within plus or minus five percent;
source positioning accuracy to within plus or minus one millimeter;
source retraction with backup battery upon power failure;
length of the source transfer tubes;
timer accuracy and linearity over the typical range of use;
length of the applicators; and
function of the source transfer tubes, applicators, and transfer tube-applicator interfaces.
A licensee must use the dosimetry system described in part 4731.4468, subpart 1, to measure the output.
A licensee must make full calibration measurements required under subpart 1 according to published protocols accepted by nationally recognized bodies.
In addition to the requirements for full calibrations for low dose-rate remote afterloader units under subpart 2, a licensee must perform an autoradiograph of the source to verify inventory and source arrangement at intervals not exceeding one quarter.
For low dose-rate remote afterloader units, a licensee may use measurements provided by the source manufacturer that are made according to subparts 1 to 5.
A licensee must mathematically correct the outputs determined in subpart 2, item A, for physical decay at intervals consistent with one percent physical decay.
Full calibration measurements required under subpart 1 and physical decay corrections required under subpart 7 must be performed by the authorized medical physicist.
29 SR 755
March 12, 2009
Official Publication of the State of Minnesota
Revisor of Statutes