Minn. R. agency 144, ch. 4731, MEDICAL USE OF RADIOACTIVE MATERIAL, pt. 4731.4470

Current through Register Vol. 49, No. 29, 2025

Part 4731.4470 - REMOTE AFTERLOADER UNITS; FULL CALIBRATION

Subpart 1.Calibration required.

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

A. before the first medical use of the unit;

B. before medical use under the following conditions:

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

(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;

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

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

Subp. 2.Required determinations.

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

A. the output within plus or minus five percent;

B. source positioning accuracy to within plus or minus one millimeter;

C. source retraction with backup battery upon power failure;

D. length of the source transfer tubes;

E. timer accuracy and linearity over the typical range of use;

F. length of the applicators; and

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

Subp. 3.Required system.

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

Subp. 4.Required protocols.

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

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.

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.

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.

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.

Subp. 9.Record retention.

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

Minn. R. agency 144, ch. 4731, MEDICAL USE OF RADIOACTIVE MATERIAL, pt. 4731.4470

29 SR 755

Statutory Authority: MS s 144.1202; 144.1203