Monte Carlo dose voxel kernel calculations of beta-emitting and Auger-emitting radionuclides for internal dosimetry: A comparison between EGSnrcMP and EGS4

Lidia Strigari, Enrico Menghi, Marco D'Andrea, Marcello Benassi

Research output: Contribution to journalArticle

Abstract

Dose-point kernels (DPKs) can be widely applied to therapeutic nuclear medicine to obtain more accurate absorbed dose assessments in internal dosimetry assuming a spherical geometry. Recently, EGSnrc - the latest in the family of EGS Monte Carlo codes - has been tested for isotropic monoenergetic electrons and Y-90 beta spectrum in spherical geometry. The availability of SPECT images allows one to take into account heterogeneities in activity distribution within tumors, and to perform dose calculations using voxel dosimetry based on Monte Carlo simulations in a Cartesian geometry. The purpose of this study is to evaluate the differences of dose distributions scored in Cartesian voxels also known as Dose Voxel Kernels (DVKs) for five beta-emitting (131I, 89Sr, 153Sm, 186Re, and 90Y) and Auger-emitting (111In) radionuclides, when their computation is made using these two Monte Carlo codes from the same family to check if the new physics in EGSnrc simulation system produces DVK very different from those calculated with EGS4. We have calculated the DVKs for point and voxel sources in Cartesian scoring grids of different spatial resolutions. Our results for the point source, scored in the finer spatial resolution, show a poor agreement between EGSnrc and EGS4 (up to about 20%) for voxels closer to the origin, and a better agreement (below 5%) for longer distances for all radionuclides. For the voxel source, where doses were scored in the coarser spatial resolution, dose deposition in the central voxel is in good agreement for all the radionuclides; while surrounding voxels exhibit a slightly worse agreement.

Original languageEnglish
Pages (from-to)3383-3389
Number of pages7
JournalMedical Physics
Volume33
Issue number9
DOIs
Publication statusPublished - 2006

Keywords

  • Dose point kernel
  • Dosimetry
  • Radioimmunotherapy

ASJC Scopus subject areas

  • Biophysics

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