Gafchromic film dosimetry of a new HDR 192 Ir brachytherapy source

High‐dose‐rate (HDR) brachytherapy is a popular modality for treating cancers of the prostate, cervix, endometrium, breast, skin, bronchus, esophagus, and head and neck as well as soft‐tissue sarcomas. Because of different source designs and licensing issues, there is a need for specific dosimetry dataset for each HDR source model. The main objective of the present work is to measure 2D relative dose distribution around a new prototype  192 Ir source, referred to as IRAsource‐HDR, in PMMA phantom in the framework of AAPM TG‐43 and TG‐55 recommendations for radial distances of 0.5 cm to 4 cm. Radiochromic films (RCFs) Gafchromic EBT and HD‐810 were used for measurements. The dose rate constant, Λ, of the source was determined to be 1.084 ± 4.6 % , 1.129 ± 4.4 % , and 1.112 ± 0.8 %   cGyh − 1U − 1using EBTRCF, HD‐810 RCF, and Monte Carlo (MC) simulation, respectively. The results obtained in this study are in good agreement with previously published data for HDR interstitial  192 Ir ‐HDR sources with a maximum discrepancy of ± 4.5 % . An acceptable agreement (within ± 2 % ) between MC calculations and RCFs measurements showed that HD‐810 RCF dosimetry is as good as EBTRCF, within HDR brachytherapy, and justifies the use of specific data for this new source. These data could be used as a benchmark for dose calculations in the conventional brachytherapy treatment planning systems. PACS number(s): 87.56.bg