title: Calculation of absorbed energy in the gastrointestinal tract.
abstract: One goal of this research was to reproduce the photon specific absorbed fraction calculations of Cristy and Eckerman using their gastrointestinal (GI) tract model. A second goal was to calculate photon specific absorbed fraction values for their GI tract model using electron tracking techniques. A final goal was to calculate electron absorbed fraction values for their GI tract model. This paper summarizes the work performed using the currently accepted model of the GI tract provided by Cristy and Eckerman. Their model was coded into the Electron Gamma Shower 4 (EGS4) computational package for calculation of photon specific absorbed fraction values. To benchmark the initial code, the EGS4 program was run so that all secondary particles deposited their energy at the site of the primary photon interaction (i.e., without electron tracking). The results obtained from these preliminary calculations were compared to those provided by Cristy and Eckerman to verify and benchmark the program. Next, specific absorbed fraction values were calculated for twelve discrete photon energies using the electron tracking capabilities of EGS4. These photon specific absorbed fraction values were compared to those calculated without electron tracking. Finally, absorbed fraction values were calculated for twelve discrete electron energies. The electron absorbed fraction values were compared to those calculated without electron tracking. Finally, absorbed fraction values were calculated for twelve discrete electron energies. The electron absorbed fraction values were compared to the ICRP "one-half assumption" for electron energy deposition in the wall of the GI tract.
authors.affiliation: Argonne National Laboratory-West, Idaho Falls, ID 83403-2528, USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Poston
authors.forename: K A
authors.initials: KA
authors.lastname: Kodimer
authors.forename: W E
authors.initials: WE
authors.lastname: Bolch
authors.forename: J W
authors.initials: JW
authors.lastname: Poston
mesh_terms: D004064:Digestive System / Q000528:radiation effects*; D004583:Electrons; D006801:Humans; D009010:Monte Carlo Method; D017785:Photons; D011829:Radiation Dosage