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IVBTMC , A Monte Carlo dose calculation tool for intravascular brachytherapy
Author(s) -
Chibani Omar,
Li X. Allen
Publication year - 2003
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.1528177
Subject(s) - monte carlo method , brachytherapy , curvature , dosimetry , kerma , phase space , computational physics , physics , optics , nuclear medicine , geometry , mathematics , statistics , medicine , radiation therapy , thermodynamics
A new Monte Carlo code ( IVBTMC ) is developed for accurate dose calculations in intravascular brachytherapy (IVBT). IVBTMC calculates the dose distribution of a brachytherapy source with arbitrary size and curvature in a general three‐dimensional heterogeneous medium. Both beta and gamma sources are considered. IVBTMC is based on a modified version of the EGSNRC code. A voxel‐based geometry is used to describe the target medium incorporating heterogeneities with arbitrary composition and shape. The source term is modeled using appropriate phase‐space data. The phase‐space data are calculated for three widely used sources ( 32 P ,90 Sr / 90 Y , and192 Ir ) . To speed up dose calculations for gamma sources, a special version of IVBTMC based on the kerma approximation is developed. The accuracy of the phase‐space data model is verified and IVBTMC is validated against other Monte Carlo codes and against reported measurements using radio‐chromic films. To illustrate the IVBTMC capabilities, a variety of examples are treated.32 P ,90 Sr / 90 Y , and192 Ir sources with different lengths and degrees of curvature are considered. Calcified plaques with regular and irregular shapes are modeled. The dose distributions are calculated with a spatial resolution ranging between 0.1 and 0.5 mm. They are presented in terms of isodose contour plots. The dosimetric effects of the source curvature and/or the presence of calcified plaques are discussed. In conclusion, IVBTMC has the capability to perform high‐precision IVBT dose calculations taking into account the realistic configurations of both the source and the target medium. Key Words: Intravascular Brachytherapy, Monte Carlo, Dosimetry, Heterogeneity, Calcified Plaque, Source curvature.