Determination of the radial dose distribution at proximal distances from a high dose rate (HDR) ¹⁹²Ir source using radiochromic film

High dose rate (HDR) ¹⁹²Ir sources in remote afterloaders can be used for endovascular brachytherapy applications, such as restenosis prevention. Therefore, the determination of accurate dose distribution at proximal distances (i.e., 0.1-1.0 cm) from an HDR ¹⁹²Ir source is crucial for the success of treatments. Currently, information about the dose distribution at such distances is available mostly from Monte Carlo calculations. On the other hand, measured data are scarce due to the difficulty of accurate measurements over a very steep dose gradient region. In this study, the radial dose distribution from an HDR ¹⁹²Ir source (Nucletron Corporation, Columbia, Maryland) was measured between 0.15 and 1.0 cm using radiochromic film. Results are in agreement with published Monte Carlo data within the statistical error of measured data (±1σ). Our results suggest that radiochromic film, with an elaborate experimental setup and careful analysis, can be used to determine dosimetric parameters at proximal distances from an HDR source within an acceptable experimental error.