N.H. Admin. Code § He-P 4035.54

Current through Register No. 45, November 7, 2024

Section He-P 4035.54 - Full Calibration Measurements on Teletherapy Units, Remote Afterloader Units, and Gamma Stereotactic Radiosurgery Units

(a) A licensee authorized to use a teletherapy unit for medical use shall perform full calibration measurements on each teletherapy unit as follows:

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

(2) Before medical use under the following conditions:

a. Whenever spot check measurements indicate that the output differs by more than 5 percent from the output obtained at the last full calibration corrected mathematically for radioactive decay;

b. Following replacement of the source or following reinstallation of the teletherapy unit in a new location; and

c. 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

(3) At intervals not exceeding one year.

(b) To satisfy the requirement of He-P 4035.54(a), full calibration measurements shall include determination of:

(1) The output within +/- 3 percent for the range of field sizes and for the distance or range of distances used for medical use;

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

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

(4) Timer accuracy and linearity over the range use;

(5) "On-off" error; and

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

(c) A licensee shall use the dosimetry system described in He-P 4035.53(a) through (f) to measure the output for one set of exposure conditions, and the remaining radiation measurements required in He-P 4035.54(b)(1) shall then be made using a dosimetry system that indicates relative dose rates.

(d) A licensee shall make full calibration measurements required by He-P 4035.54(a) in accordance with published protocols accepted by nationally recognized bodies.

(e) A licensee shall correct mathematically the outputs determined in He-P 4035.54(b)(1) for physical decay for intervals not exceeding one month for cobalt-60, intervals not exceeding 6 months for cesium-137, or at intervals consistent with one percent decay for all other nuclides.

(f) Full calibration measurements required by He-P 4035.54(a) and physical decay corrections required by He-P 4035.54(e) shall be performed by an authorized medical physicist. A licensee shall retain a record of each calibration in accordance with He-P 4035.54(u) and (v).

(g) A licensee authorized to use a remote afterloader unit for medical use shall perform full calibration measurements on each unit:

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

(2) Before medical use under the following conditions:

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

b. Following any repair of the unit that includes removal of the source or major repair of the components associated with the source exposure assembly; and

(3) At intervals not exceeding 3 months for high dose-rate, medium dose-rate, and pulsed dose-rate remote afterloader units with sources whose half-life exceeds 75 days; and

(4) At intervals not exceeding 1 year for low dose-rate remote afterloader units.

(h) To satisfy the requirement of He-P 4035.54(g), full calibration measurements shall include, as applicable, determination of:

(1) The output within +/- 5 percent;

(2) Source positioning accuracy to within +/- 1 millimeter;

(3) Source retraction with backup battery upon power failure;

(4) Length of the source transfer tubes;

(5) Timer accuracy and linearity over the typical range of use;

(6) Length of the applicators; and

(7) Function of the source transfer tubes, applicators, and transfer tube-applicator interfaces.

(i) A licensee shall use the dosimetry system described in He-P 4035.53(a) through (f) to measure the output.

(j) A licensee shall make full calibration measurements required in He-P 4035.54(g) in accordance with published protocols accepted by nationally recognized bodies.

(k) In addition to the requirements for full calibration for low dose-rate remote afterloaders in He-P 4035.54(h), a licensee shall perform an autoradiograph of the source(s) to verify inventory and source(s) arrangement at intervals not exceeding 3 months.

(l) For low dose-rate remote afterloader units, a licensee shall use measurements provided by the source manufacturer that are made in accordance with He-P 4035.54(g) through (k).

(m) A licensee shall mathematically correct the outputs determined in He-P 4035.54(h)(1) for physical decay at intervals consistent with 1 percent physical decay.

(n) Full calibration measurements required by He-P 4035.54(g) and physical decay corrections required by He-P 4035.54(m) shall be performed by the authorized medical physicist. A licensee shall retain a record of each calibration in accordance with He-P 4035.54(u) and (v).

(o) A licensee authorized to use a gamma stereotactic radiosurgery unit for medical use shall perform full calibration measurements on each unit:

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

(2) Before medical use under the following conditions:

a. Whenever spot check measurements indicate that the output differs by more than 5 percent from the output obtained at the last full calibration corrected mathematically for radioactive decay;

b. Following replacement of the sources or following reinstallation of the gamma stereotactic radiosurgery unit in a new location; and

c. Following any repair of the gamma stereotactic radiosurgery unit that includes removal of the sources or major repair of the components associated with the source assembly; and

(3) At intervals not exceeding 1 year, with the exception that relative helmet factors need only be determined before the first medical use of a helmet and following any damage to a helmet.

(p) To satisfy the requirement of He-P 4035.54(o), full calibration measurements shall include determination of:

(1) The output within +/- 3 percent;

(2) Relative helmet factors;

(3) Isocenter coincidence;

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

(5) "On-off" error;

(6) Trunnion centricity;

(7) Treatment table retraction mechanism, using backup battery power or hydraulic backups with the unit off;

(8) Helmet microswitches;

(9) Emergency timing circuits; and

(10) Stereotactic frames and localizing devices (trunnions).

(q) A licensee shall use the dosimetry system described in He-P 4035.53(a) through (f) to measure the output for one set of exposure conditions. The remaining radiation measurements required in He-P 4035.54(p)(1) shall be made using a dosimetry system that indicates relative dose rates.

(r) A licensee shall make full calibration measurements required by He-P 4035.54(o) in accordance with published protocols accepted by nationally recognized bodies.

(s) A licensee shall mathematically correct the outputs determined in He-P 4035.54(p)(1) at interval not exceeding 1 month for cobalt-60 and at intervals consistent with 1 percent physical decay for all other radionuclides.

(t) Full calibration measurements required by He-P 4035.54(o) and physical decay corrections by He-P 4035.54(s) shall be performed by the authorized medical physicist. A licensee shall retain a record of each calibration in accordance with He-P 4035.54(u) and (v).

(u) A licensee shall maintain a record of each calibration of teletherapy unit, remote afterloader unit, and gamma stereotactic radiosurgery unit for 3 years.

(v) The record in (u) above shall include the date of the calibration, the manufacturer's name, model number, and serial number of the teletherapy, remote afterloader, and gamma stereotactic radiosurgery unit(s), the source(s), and the instruments used to calibrated the unit(s); the results and an assessment of the full calibrations; the results of the autograph required for low dose-rate remote afterloader units; and the signature of the authorized medical physicist who performed the full calibration.

N.H. Admin. Code § He-P 4035.54

(See Revision Note at part heading for He-P 4035) #6942, eff 2-1-99; ss by #8800, INTERIM, eff 2-1-07, EXPIRED: 7-31-07

New. #8959, eff 8-7-07

Amended by Volume XXXV, Number 32 Filed August 13, 2015, Proposed by #10897, Effective 7/22/2015, Expires1/18/2016.

Amended by Volume XXXVI Number 01, Filed January 7, 2016, Proposed by #11011, Effective 1/15/2016, Expires 1/15/2026.

Amended by Volume XL Number 24, Filed June 11, 2020, Proposed by #13048, Effective 6/2/2020, Expires 6/2/2030.