title: Estimation of Photon Specific Absorbed Fractions in Digimouse Voxel Phantom using Monte Carlo Simulation Code FLUKA.
abstract: BACKGROUND
  Most preclinical studies are carried out on mice. For internal dose assessment of a mouse, specific absorbed fraction (SAF) values play an important role. In most studies, SAF values are estimated using older standard human organ compositions and values for limited source target pairs.
  
  
  OBJECTIVE
  SAF values for monoenergetic photons of energies 15, 50, 100, 500, 1000 and 4000 keV were evaluated for the Digimouse voxel phantom incorporated in Monte Carlo code FLUKA. The organ sources considered in this study were lungs, skeleton, heart, bladder, testis, stomach, spleen, pancreas, liver, kidney, adrenal, eye and brain. The considered target organs were lungs, skeleton, heart, bladder, testis, stomach, spleen, pancreas, liver, kidney, adrenal and brain. Eye was considered as a target organ only for eye as a source organ. Organ compositions and densities were adopted from International Commission on Radiological Protection (ICRP) publication number 110.
  
  
  RESULTS
  Evaluated organ masses and SAF values are presented in tabular form. It is observed that SAF values decrease with increasing the source-to-target distance. The SAF value for self-irradiation decreases with increasing photon energy. The SAF values are also found to be dependent on the mass of target in such a way that higher values are obtained for lower masses. The effect of composition is highest in case of target organ lungs where mass and estimated SAF values are found to have larger differences.
  
  
  CONCLUSIONS
  These SAF values are very important for absorbed dose calculation for various organs of a mouse.
authors.affiliation: Faculty of Physical Sciences, Shri Ramswaroop Memorial University, Lucknow, India.
authors.forename: A
authors.initials: A
authors.lastname: Sinha
authors.affiliation: Bhabha Atomic Research Center, Mumbai, India.
authors.forename: H K
authors.initials: HK
authors.lastname: Patni
authors.affiliation: Faculty of Physical Sciences, Shri Ramswaroop Memorial University, Lucknow, India.
authors.forename: B M
authors.initials: BM
authors.lastname: Dixit
authors.affiliation: Department of Radiotherapy, King George Medical University, Lucknow, India.
authors.forename: N K
authors.initials: NK
authors.lastname: Painuly
authors.affiliation: Department of Radiotherapy, King George Medical University, Lucknow, India.
authors.forename: N
authors.initials: N
authors.lastname: Singh
keywords:  Digimouse Voxel Phantom ;  FLUKA;  Monte Carlo Simulation ; Specific Absorbed Fraction 