title: Practical Nuclear Medicine and Utility of Phantoms for Internal Dosimetry: XCAT Compared with Zubal.
abstract: OBJECTIVE
  The absorbed doses for two radioisotopes, 99mTc and 131I, between previously validated Zubal phantom and the recently developed XCAT phantom were compared.
  
  
  METHODS
  GATE Monte Carlo code was used to simulate the statistical process of radiation. A XCAT phantom with voxel and matrix sizes similar to a standard Zubal phantom was generated. According to Medical International Radiation Dose formalism, specific absorbed fraction (SAF) values for photons and S-factors for beta particles were tabulated. The amounts of absorbed doses were calculated and compared in different organs.
  
  
  RESULTS
  The differences of gamma radiation doses, SAFs, between Zubal and XCAT are >50% in adrenal from adrenal, pancreas from pancreas and thyroid from thyroid, in lung from kidney, kidneys from lungs and in kidneys from thyroid and thyroid from kidneys. The beta radiation doses differences between Zubal and XCAT are >50% in thyroid from thyroid, bladder from bladder, kidney from kidney, liver from bladder, thyroid from bladder and kidney from thyroid. The size and distances of the organs were different between XCAT and Zubal phantoms. Denoted differences of SAF and S-factors correspond to the different organ geometries in phantoms.
  
  
  CONCLUSIONS
  The results of absorbed doses in Zubal and XCAT phantoms are different. The variations prohibit easy comparison or interchangeability of dosimetry between these phantoms.
authors.affiliation: Department of Nuclear Medicine, Vali-Asr Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran 1419731351, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Fallahpoor
authors.affiliation: Department of Nuclear Medicine, Vali-Asr Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran 1419731351, Iran.
authors.forename: Mehrshad
authors.initials: M
authors.lastname: Abbasi
authors.affiliation: Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, Texas 75235.
authors.forename: Faraz
authors.initials: F
authors.lastname: Kalantari
authors.affiliation: Department of Medical Physics, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
authors.forename: Ali Asghar
authors.initials: AA
authors.lastname: Parach
authors.affiliation: Department of Biomedical Engineering, University of Houston, Houston, Texas 77004.
authors.forename: Anando
authors.initials: A
authors.lastname: Sen
mesh_terms: D006801:Humans; D009010:Monte Carlo Method; D009683:Nuclear Medicine; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011874:Radiometry