title: A comparison between GATE4 results and MCNP4B published data for internal radiation dosimetry.
abstract: OBJECTIVE
  GATE, has been designed as upper layer of the GEANT4 toolkit for nuclear medicine application including internal dosimetry. However, its results have not been fully compared to the well-developed codes and anthropomorphic voxel phantoms have never been used with GATE/GEANT for internal dosimetry. The aim of present study was to compare the internal dose calculated by GATE/GEANT with the MCNP4B published data.
  
  
  METHODS
  The Zubal phantom was used to model a typical adult male. Activity was assumed uniformly distributed in liver, kidneys, lungs, spleen, pancreas and adrenals. GATE/GEANT Monte Carlo package was used for estimation of doses in the phantom. Simulations were performed for photon energy of 0.01-1 MeV and mono-energetic electrons of 935 keV. Specific absorbed fractions for photons and S-factors for electrons were calculated.
  
  
  RESULTS
  On average, GATE/GEANT produces higher photon SAF (Specific Absorbed Fraction) values (+2.7%) for self-absorption and lower values (-2.9%) for cross-absorption. The difference was higher for paired organs particularly lungs. Moreover the photon SAF values for lungs as source organ at the energy of 200 and 500 keV was considerably higher with MCNP4B compared to GATE.
  
  
  CONCLUSIONS
  Despite of differences between the GATE4 and MCNP4B, the results can be considered ensuring. This may be considered as validation of GATE/GEANT as a proprietary code in nuclear medicine for radionuclide dosimetry applications.
authors.affiliation: Dept. of Medical Physics, Faculty of Medical Sciences, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran. hRajabi@modares.ac.ir
authors.forename: A A
authors.initials: AA
authors.lastname: Parach
authors.forename: H
authors.initials: H
authors.lastname: Rajabi
mesh_terms: D009010:Monte Carlo Method; D011874:Radiometry / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012984:Software