Dose Distribution of 192Ir HDR Brachytherapy Source Measurement using Gafchromic® EBT3 Film Dosimeter and TLD-100H

This study aims to measure the radial dose function and anisotropy function F(r, theta) of High Dose Rate (HDR) Ir-192 source in a fabricated water-equivalent phantom using Gafchromic (R) EBT3 film and TLD-100H and to compare the results obtained with the MCNP5 calculated values. The phantom was fabricated using Perspex PMMA material. For, the EBT3 films with a required dimension and TLD-100H chips were placed at r=1, 2, 3, 5, and 10 cm from the source. The F(r, theta) measurements were carried out at r=1, 2, 3, 5, and 10 cm with the angle range from 10 degrees to 170 degrees. The result of from EBT3 film and TLD-100H was in good agreement (2.10%+/- 1.99). Compared to MCNP5, the differences are within 0.31% to 11.47% for EBT3 film and 0.08% to 10.58% for TLD-100H. For the F(r, theta), an average deviation with the MCNP5 calculation is 4.94%+/- 2.7. For both and F(r, theta), the effects are prominent at r=10 cm. At this distance, the response of both Gafchromic (R) EBT3 film and TLD-100H shows less sensitivity as the dose followed the inverse square law. This work demonstrates that Gafchromic (R) EBT3 film dosimeter and TLD-100H are suitable dosimeters in 192Ir dosimetric measurements at a radial distance of <5 cm.