Kyveli Zourari, Manos Zoros, Eleftherios Pappas, Evaggelos Pantelis, Pantelis Karaiskos and Panagiotis Papagiannis
Posters-Accepted Abstracts: J Nucl Med Radiat Ther
Monte Carlo (MC) simulation is considered the reference computational method for dosimetry in radiation therapy applications. While it has been proposed for the treatment planning of brachytherapy using low energy sources, calculation times remain impractical for 192Ir brachytherapy. This work reports on the preparation of virtual brachytherapy sources for use in MC simulations to reduce memory requirements and improve calculation efficiency. MC simulation was performed using MCNP6 to record the phase-space file (a source-specific file containing the energy, position, and direction of photons emerging from a source) for a generic 192Ir brachytherapy source proposed recently for the evaluation of commercially available dose calculation algorithms. 6 Ã? 107 initially emitted photons were sampled resulting to a phase-space file size on the order of GBs. The accuracy of the phase-space file was verified through benchmarking of single source dosimetry results. The photon energy distribution was found to have no association with position along the source longitudinal axis, z, polar angle, Ï?, and, of course, azimuthal angle, θ. The z-distribution of emitted photons was transformed to a probability density distribution and fit to a sum of two p-sigmoid distributions. The probability density function for Ï? is decribed by a family of normal distributions over z described by their mean and standard deviation as a function of z. Hence a brachytherapy source can be described by a file of size on the order of kB to sample: photon energy from a discrete distribution, position z from a a sum of two p-sigmoid distributions, Ï? from a normal distribution depending on z, and θ uniformly.
Nuclear Medicine & Radiation Therapy received 706 citations as per Google Scholar report
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