Radiochromic film measurement of anisotropy function for high-dose-rate Ir-192 brachytherapy source

Abstract

The dose distribution produced by the high-dose-rate (HDR) 192Ir source is inherently anisotropic due to self-absorption by the high-density source core, oblique filtration by the source capsule and the asymmetric geometry of the source capsule. To account for the dose distribution anisotropy of brachytherapy sources, AAPM Task Group No 43 has included a two-dimensional anisotropy function, F(r, theta), in the recommended dose calculation formalism. Gafchromic HS radiochromic film (RCF) was used to measure anisotropy function for microSelectron HDR 192Ir source (classic/old design). Measurements were carried out in a water phantom using specially fabricated PMMA cylinders at radial distances 1, 2, 3, 4 and 5 cm. The data so generated are comparable to both experimental and Monte Carlo calculated values for this source reported earlier by other authors. The RCF method described in this paper is comparatively high resolution, simple to use and is a general method, which can be applied for other brachytherapy sources as well.

Gafchromic film dosimetry of a new HDR brachytherapy source

“…In recent years, many attempts have been made to perform the dosimetry of ${\hspace{0.17em}}^{192}\text{Ir}$‐HDR brachytherapy sources using radiochromic films (RCFs) 5 , 6 , 7 , 8 , 9 . Piermattei et al (5) performed experimental dosimetry of the MicroSelectron HDR ${\hspace{0.17em}}^{192}\text{Ir}$ source model 080950 (Elekta AB, Stockholm, Sweden), used for the brachytherapy of peripheral vessels in a water phantom with high sensitivity (HS) RCF.…”

Measurement of absorbed dose‐to‐water for an HDR 192Ir source with ionization chambers in a sandwich setup

“…[9][10][11][12] On the other hand, to date, the determination of absorbed dose in water or plastic phantoms for HDR 192 Ir brachytherapy sources has been reported for direct inphantom measurements using detectors such as Fricke dosimeters, 13,14 thermoluminescent dosimeters, 3,4 radiophotoluminescent glass dosimeters, 15 ionization chamber dosimeters, [16][17][18][19][20][21][22] diode dosimeters, 3 metal-oxide semiconductor field-effect transistor dosimeters, 23 and Gafchromic film dosimeters. 21,22,24,25 Absorbed dose standards for HDR 192 Ir sources based on water and graphite calorimeters have recently been developed in the framework of the European Metrology Research Programme (EMRP) from 2008 to 2011. 26,27 However, these absorbed dose standards have not yet been fully established at primary standards laboratories, and a standard dosimetry protocol based on absorbed dose for brachytherapy has not been published yet.…”

A Study on the Dose Distributions in Various Materials from an Ir-192 HDR Brachytherapy Source

“…Gafchromic film (MD-55, Nuclear Associates, USA) was used due to its excellent spatial resolution (0.2 mm), tissue equivalent 6.5 atomic number, and low sensitivity to room luminosity [19], [20], [21]. The MD-55 has a thickness of approximately 0.3 mm and dose ranges from 3 to 100 Gy.…”