Nebraska Administrative Code
Topic - HEALTH AND HUMAN SERVICES SYSTEM
Title 180 - CONTROL OF RADIATION
Chapter 7 - MEDICAL USE OF RADIOACTIVE MATERIAL
Section 180-7-073 - FULL CALIBRATION MEASUREMENTS ON TELETHERAPY UNITS

Universal Citation: 180 NE Admin Rules and Regs ch 7 ยง 073

Current through September 17, 2024

073.01 FREQUENCY. A licensee authorized to use a teletherapy unit for medical use must perform full calibration measurements on each teletherapy unit:

(A) Before the first medical use of the unit;

(B) Before medical use under the following conditions:
(i) Whenever spot-check measurements indicate that the output differs by more than 5% from the output obtained at the last full calibration corrected mathematically for radioactive decay;

(ii) Following replacement of the source or following reinstallation of the teletherapy unit in a new location; and

(iii) Following any repair of the teletherapy unit that includes removal of the source or major repair of the components associated with the source exposure assembly; and

(C) At intervals not exceeding one year.

073.02 DETERMINANTS. To satisfy the requirement of 180 NAC 7-073.01, full calibration measurements must include determination of:

(A) The output within plus or minus 3% for the range of field sizes and for the distance or range of distances used for medical use;

(B) The coincidence of the radiation field and the field indicated by the light beam localizing device;

(C) The uniformity of the radiation field and its dependence on the orientation of the useful beam;

(D) Timer accuracy, and linearity over the range of use;

(E) "On-off" error; and

(F) The accuracy of all distance measuring and localization devices in medical use.

073.03 DOSIMETRY SYSTEM USAGE. A licensee must use the dosimetry system described in 180 NAC 7-072.01 to measure the output for one set of exposure conditions. The remaining radiation measurements required by 7-073.02(A) may then be made using a dosimetry system that indicates relative dose rates.

073.04 PROTOCOLS. A licensee must make full calibration measurements required by 180 NAC 7-073.01 according to published protocols accepted by nationally recognized bodies.

073.05 MATHEMATICAL CORRECTION OF OUTPUTS. A licensee must mathematically correct the outputs determined in 180 NAC 7-073.02, (A), for physical decay for intervals not exceeding one month for cobalt-60, six months for cesium-137, or at intervals consistent with 1% decay for all other nuclides.

073.06 CALIBRATION MEASUREMENT AND DECAY CORRECTIONS. Full calibration measurements required by 180 NAC 7-073.01 and physical decay corrections required by 180 NAC 7-073.05 must be performed by an authorized medical physicist.

073.07 RECORDS. A licensee must maintain a record of each calibration according to 180 NAC 7-108.

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