https://doi.org/10.1140/epjp/s13360-025-07058-6
Regular Article
Effect of inhomogeneous phantom on dosimetric characteristics of 103Pd brachytherapy source
Physics Department, Faculty of Sciences, Sahand University of Technology, Tabriz, Iran
a
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Received:
7
September
2025
Accepted:
10
November
2025
Published online:
17
November
2025
Abstract
Current brachytherapy treatment planning systems (TPS) typically use dosimetric parameters in liquid water for dose calculations, ignoring tissue heterogeneity. This study assessed how sensitive the radial dose function (g(r)) of 103Pd brachytherapy seed was to variations in bone and breast calcification. To this end, Monte Carlo (MC)-based radiation transport simulations were performed using the MCNP code and g(r) quantity was obtained at heterogeneous spherical phantoms. The ratio of the g(r) in the heterogeneous phantom to the uniform soft tissue phantom was determined for different bone thickness and breast calcification percentages. These findings showed that the maximum g(r) ratio of cortical bone thicknesses with 0.5 and 1 cm was 1.86 ± 6.24E−03 and 1.85 ± 5.38E−03, respectively, within the heterogeneity region. This value was 3.14 ± 3.46E−02 and 6.50E−01 ± 5.36E−03, for 20% and 100% breast adipose calcification with thickness of 0.5 cm, respectively, while this ratio was 2.75 ± 3.19E−02 and 5.65E−01 ± 5.50E−03, for 20% and 100% breast glandular calcification with thickness of 0.5 cm, respectively. Due to more photon attenuation inside the high-density tissue, the g(r) ratio was decreased to 4.38E−02 ± 6.73E−04 and 8.33E−03 ± 2.50E−04 just after the 0.5 and 1 cm thickness of cortical bone, respectively. Furthermore, the relative difference of g(r) was about − 100% for higher levels of breast calcification immediately after the heterogeneity region.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2025
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
