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Title: Deterministic photon kerma distribution based on the Boltzmann equation for external beam radiation therapy

Journal Article · · Medical Physics
DOI:https://doi.org/10.1118/1.2960247· OSTI ID:21120916
; ;  [1]
  1. ICT Radiotherapy, Livingston, New Jersey 07039 (United States)

A photon transport algorithm for fully three-dimensional radiotherapy treatment planning has been developed based on the discrete ordinates (S{sub N}) solution of the Boltzmann equation. The algorithm is characterized by orthogonal adaptive meshes, which place additional points where large gradients occur and a procedure to evaluate the collided flux using the representation of spherical harmonic expansion instead of the summation of the volume-weighted contribution from discrete angles. The Boltzmann equation was solved in the form of S{sub N} spatial, energy, and angular discretization with mitigation of ray effects by the first-collision source method. Unlike existing S{sub N} codes, which were designed for general purpose for multiparticle transport in areas such as nuclear engineering, our code is optimized for medical radiation transport. To validate the algorithm, several examples were employed to calculate the photon flux distribution. Numerical results show good agreement with the Monte Carlo calculations using EGSnrc.

OSTI ID:
21120916
Journal Information:
Medical Physics, Vol. 35, Issue 9; Other Information: DOI: 10.1118/1.2960247; (c) 2008 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-2405
Country of Publication:
United States
Language:
English