AI Article Synopsis
- Brazil has over 100 HDR brachytherapy facilities using well-type chambers for measuring the air kerma rate of 192Ir sources, with a calibration methodology developed by the Laboratorio de Ciencias Radiologicas (LCR).
- The calibration system showed a maximum deviation of only 1.0% between the coefficients obtained and those from the UWADCL calibration certificate, establishing strong reliability.
- Direct comparisons between LCR and UWADCL resulted in a 0.9% agreement for the calibration coefficients, demonstrating consistent results and highlighting the effectiveness of the developed calibration system.
Article Abstract
In Brazil there are over 100 high dose rate (HDR) brachytherapy facilities using well-type chambers for the determination of the air kerma rate of 192Ir sources. This paper presents the methodology developed and extensively tested by the Laboratorio de Ciencias Radiologicas (LCR) and presently in use to calibrate those types of chambers. The system was initially used to calibrate six well-type chambers of brachytherapy services, and the maximum deviation of only 1.0% was observed between the calibration coefficients obtained and the ones in the calibration certificate provided by the UWADCL. In addition to its traceability to the Brazilian National Standards, the whole system was taken to the University of Wisconsin Accredited Dosimetry Calibration Laboratory (UWADCL) for a direct comparison and the same formalism to calculate the air kerma was used. The comparison results between the two laboratories show an agreement of 0.9% for the calibration coefficients. Three Brazilian well-type chambers were calibrated at the UWADCL, and by LCR, in Brazil, using the developed system and a clinical HDR machine. The results of the calibration of three well chambers have shown an agreement better than 1.0%. Uncertainty analyses involving the measurements made both at the UWADCL and LCR laboratories are discussed.
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