4731.4470 REMOTE AFTERLOADER UNITS; FULL CALIBRATION.


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Subpart 1.

Calibration required.

A licensee authorized to use a remote afterloader unit for medical use must perform full calibration measurements on each unit:

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A.

before the first medical use of the unit;


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B.

before medical use under the following conditions:

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(1)

following replacement of the source or following reinstallation of the unit in a new location outside the facility; and


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(2)

following any repair of the unit that includes removal of the source or major repair of the components associated with the source exposure assembly;



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C.

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


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D.

at intervals not exceeding one year for low dose-rate remote afterloader units.



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Subp. 2.

Required determinations.

To satisfy subpart 1, full calibration measurements must include, as applicable, determination of:

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A.

the output within plus or minus five percent;


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B.

source positioning accuracy to within plus or minus one millimeter;


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C.

source retraction with backup battery upon power failure;


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D.

length of the source transfer tubes;


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E.

timer accuracy and linearity over the typical range of use;


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F.

length of the applicators; and


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G.

function of the source transfer tubes, applicators, and transfer tube-applicator interfaces.



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Subp. 3.

Required system.

A licensee must use the dosimetry system described in part 4731.4468, subpart 1, to measure the output.


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Subp. 4.

Required protocols.

A licensee must make full calibration measurements required under subpart 1 according to published protocols accepted by nationally recognized bodies.


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Subp. 5.

Autoradiograph required.

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.


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Subp. 6.

Measurements by manufacturer.

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.


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Subp. 7.

Required corrections.

A licensee must mathematically correct the outputs determined in subpart 2, item A, for physical decay at intervals consistent with one percent physical decay.


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Subp. 8.

Authorized medical physicist.

Full calibration measurements required under subpart 1 and physical decay corrections required under subpart 7 must be performed by the authorized medical physicist.


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Subp. 9.

Record retention.

A licensee must retain a record of each calibration according to part 4731.4518.