title: A comparison between EGS4 and MCNP computer modeling of an in vivo X-ray fluorescence system.
abstract: The Monte Carlo computer codes EGS4 and MCNP were used to develop a theoretical model of a 180 degrees geometry in vivo X-ray fluorescence system for the measurement of platinum concentration in head and neck tumors. The model included specification of the photon source, collimators, phantoms and detector. Theoretical results were compared and evaluated against X-ray fluorescence data obtained experimentally from an existing system developed by the Swansea In Vivo Analysis and Cancer Research Group. The EGS4 results agreed well with the MCNP results. However, agreement between the measured spectral shape obtained using the experimental X-ray fluorescence system and the simulated spectral shape obtained using the two Monte Carlo codes was relatively poor. The main reason for the disagreement between the results arises from the basic assumptions which the two codes used in their calculations. Both codes assume a "free" electron model for Compton interactions. This assumption will underestimate the results and invalidates any predicted and experimental spectra when compared with each other.
authors.affiliation: Department of Physics, Faculty of Applied Sciences, Umm Al-Qura University, Makkah, P.O. Box 10130, Saudi Arabia. alghorabie@hotmail.com
authors.forename: F H
authors.initials: FH
authors.lastname: Al-Ghorabie
authors.forename: S S
authors.initials: SS
authors.lastname: Natto
authors.forename: S H
authors.initials: SH
authors.lastname: Al-Lyhiani
mesh_terms: D003198:Computer Simulation; D006258:Head and Neck Neoplasms / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008432:Mathematical Computing; D009010:Monte Carlo Method; D019047:Phantoms, Imaging; D010984:Platinum / Q000032:analysis* / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013052:Spectrometry, X-Ray Emission; D014980:Xenon Radioisotopes
chemical_list: D014980:Xenon Radioisotopes; D010984:Platinum