A comparison of dose distribution between Scan2MCNP and CT2MCNP programs for brachytherapy of brain tumours

Abstract

Author(s): Hadi Nasrollahi*, Mohsen Hasani, Hasan Ali Nedaei and Hamideh Naderi

Introduction: The use of Monte Carlo simulation methods is assumed to be one of the most accurate methods for calculation of dose distribution in a patient's body. Two pieces of software in MCNP code, which are applied for body simulation, are Scan2MCNP and CT2MCNP that operate based on the intensity of DICOM colour images and CT numbers respectively. Therefore, dose distribution obtained by these two methods is predicted to be different. The aim of this study is to evaluate dosage differences calculated by Scan2MCNP and CT2MCNP to simulate of low energy radioactive sources for brachytherapy of brain tumours. Material and methods: In this study, 125I (Model IR-Seed2) source manufactured by Iran was simulated by MCNPX code and then the accuracy of simulation was evaluated. Simulation of 125I implantation in brain was performed using Scan2MCNP and CT2MCNP programs. Comparison of the sources' implant time, isodose curves and Dose Volume Histograms (DVH) between these two pieces of software was performed. Results: The simulations showed that Scan2MCNP software, due to using higher density materials and more attenuation, predicted lower dose value compared to CT2MCNP. Conclusion: The results showed that Scan2MCNP software, because of using colour image intensities revealed in simulation of soft tissues and bone inhomogeneity, led to about 10% and 25% error, respectively.

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