Monte Carlo simulation of ruthenium eye plaques with GEANT4: influence of multiple scattering algorithms, the spectrum and the geometry on depth dose profiles

Abstract

Previous studies show remarkable differences in the simulation of electron depth dose profiles of ruthenium eye plaques. We examined the influence of the scoring and simulation geometry, the source spectrum and the multiple scattering algorithm on the depth dose profile using GEANT4. The simulated absolute dose deposition agrees with absolute dose data from the manufacturer within the measurement uncertainty. Variations in the simulation geometry as well as the source spectrum have only a small influence on the depth dose profiles. However, the multiple scattering algorithms have the largest influence on the depth dose profiles. They deposit up to 20% less dose compared to the single scattering implementation. We recommend researchers who are interested in simulating low- to medium-energy electrons to examine their simulation under the influence of different multiple scattering settings. Since the simulation and scoring geometry as well as the exact physics settings are best described by the source code of the application, we made the code publicly available.

Dose Distributions and Treatment Margins in Ocular Brachytherapy with 106Ru Eye Plaques

“…The framework Geant4 can be used to perform Monte Carlo simulations for radiation transport in tissue. The general setup and physics settings for this investigation are based on findings by Sommer et al [24]. For the radioactive decay and the composition of the different components of the eye plaque, internal Geant4 databases were used.…”

“…The determination of 3-D dose distributions is a current field of research [16,17,18,19,20,21,22,23,24]. This study is based on Monte Carlo simulated dose distributions of 3 eye plaque types.…”

Air core detectors for Cerenkov‐free scintillation dosimetry of brachytherapy β‐sources

“…In this study, simulations are used to prove that the changes in the radiation field, for example the reduction of backscattering, which are to be expected when replacing the optical fiber with air and adding additional mylar foil, do not have any significant or distance‐dependent influence on the dose deposited in the scintillator. The simulations are set up in accordance to the findings of Sommer et al for Monte‐Carlo studies of / eye plaques. Four detectors ( Std SC , AC 5 SC , AC 10 SC , and AC 17 SC ) are modeled according to their respective components and materials (cf.…”

Inhomogeneous Surface Dose Distributions of 106Ru Eye Plaques

“…For this reason, differences in dose distributions between different publications cannot be easily attributed to methodical differences on the one hand or differences in the heterogeneous distribution of the emitter substance of the eye plaques themselves on the other. Furthermore, this inhomogeneity is one of the reasons why Monte Carlo-simulated depth dose curves [2] differ from measured ones especially regarding absolute doses (Fig. 2).…”

“…2 Dose per activity along the plaque symmetry axis. Comparison between Monte Carlo (MC) simulation [2] and different eye plaques of the CCB type. Data are taken from BEBIG certificates for sealed radioactive sources. …”