Abstract
In order to apply the Monte Carlo simulation technique for usual radiological examinations we developed a Pc program, 'IradMed', written entirely in Java. The main purpose of this program is to compute the organ doses and the effective dose of patients, which are exposed at a X-ray beam having photon energies in 10 to 150 keV radiodiagnostic range. Three major radiological procedures are considered, namely mammography, radiography and CT. The fluoroscopy implies an irregular geometry and therefore it is neglected. Nevertheless, a gross estimation of patient doses can be made taking into account the fluoroscopy as being composed of several radiographic examinations applied in different anatomical regions. The interactions between radiation and matter are well-known, and the accuracy of the calculation is limited by the accuracy of the anatomical model used to describe actual patients and by characterisation of the radiation field applied. In this version of IradMed, it is assumed that the absorbed dose is equal with kerma for all tissues. No procedure has been used to take account of the finite range of the secondary electrons that are produced by photoelectric or Compton interactions. These ranges are small compared with the dimensions of the organs, and the absorbed
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Citation Formats
Fulea, D, and Cosma, C.
Real time Monte Carlo simulation for evaluation of patient doses involved in radiological examinations.
France: N. p.,
2006.
Web.
Fulea, D, & Cosma, C.
Real time Monte Carlo simulation for evaluation of patient doses involved in radiological examinations.
France.
Fulea, D, and Cosma, C.
2006.
"Real time Monte Carlo simulation for evaluation of patient doses involved in radiological examinations."
France.
@misc{etde_20892141,
title = {Real time Monte Carlo simulation for evaluation of patient doses involved in radiological examinations}
author = {Fulea, D, and Cosma, C}
abstractNote = {In order to apply the Monte Carlo simulation technique for usual radiological examinations we developed a Pc program, 'IradMed', written entirely in Java. The main purpose of this program is to compute the organ doses and the effective dose of patients, which are exposed at a X-ray beam having photon energies in 10 to 150 keV radiodiagnostic range. Three major radiological procedures are considered, namely mammography, radiography and CT. The fluoroscopy implies an irregular geometry and therefore it is neglected. Nevertheless, a gross estimation of patient doses can be made taking into account the fluoroscopy as being composed of several radiographic examinations applied in different anatomical regions. The interactions between radiation and matter are well-known, and the accuracy of the calculation is limited by the accuracy of the anatomical model used to describe actual patients and by characterisation of the radiation field applied. In this version of IradMed, it is assumed that the absorbed dose is equal with kerma for all tissues. No procedure has been used to take account of the finite range of the secondary electrons that are produced by photoelectric or Compton interactions. These ranges are small compared with the dimensions of the organs, and the absorbed dose will not change abruptly with distance except at boundary where composition and density change. However these boundary effects would have little effect in the determination of the average doses to almost all organs, except the active bone marrow which is treated separately. Another justification for this kerma approximation is the fact that the sum of all electron energies that exit the organ is statistically equal with the sum of all electron energies that enter in that particular organ. In this version of program, it is considered the following interactions: the Rayleigh scattering, the Compton scattering and the photoelectric effect. The Compton scattering is modeled by several methods which avoid the solving of Klein-Nishina equation namely 'classic', Kahn, Wielopolski and E.G.S. (taken from Electron Gamma Shower source code) algorithm. A preliminary study for angular distribution by applying all of these algorithms has been made. The best results is provided by the E.G.S.-based algorithm followed by the Kahn and the 'classic' one. The patient doses computed by applying Kahn or 'classic' algorithms are in good agreement with data from literature or with data generated by other similar Pc programs, and the small differences could be explained by the fact that different kind of mathematical phantoms have been used. Also, we can conclude that all these comparison data were based on Kahn or 'classic' algorithms for modeling the Compton scattering. In spite of these, the usage of E.G.S. based algorithm is strongly recommended. With this algorithm it was obtained smaller patient doses for several kind of radiological examinations. (authors)}
place = {France}
year = {2006}
month = {Jul}
}
title = {Real time Monte Carlo simulation for evaluation of patient doses involved in radiological examinations}
author = {Fulea, D, and Cosma, C}
abstractNote = {In order to apply the Monte Carlo simulation technique for usual radiological examinations we developed a Pc program, 'IradMed', written entirely in Java. The main purpose of this program is to compute the organ doses and the effective dose of patients, which are exposed at a X-ray beam having photon energies in 10 to 150 keV radiodiagnostic range. Three major radiological procedures are considered, namely mammography, radiography and CT. The fluoroscopy implies an irregular geometry and therefore it is neglected. Nevertheless, a gross estimation of patient doses can be made taking into account the fluoroscopy as being composed of several radiographic examinations applied in different anatomical regions. The interactions between radiation and matter are well-known, and the accuracy of the calculation is limited by the accuracy of the anatomical model used to describe actual patients and by characterisation of the radiation field applied. In this version of IradMed, it is assumed that the absorbed dose is equal with kerma for all tissues. No procedure has been used to take account of the finite range of the secondary electrons that are produced by photoelectric or Compton interactions. These ranges are small compared with the dimensions of the organs, and the absorbed dose will not change abruptly with distance except at boundary where composition and density change. However these boundary effects would have little effect in the determination of the average doses to almost all organs, except the active bone marrow which is treated separately. Another justification for this kerma approximation is the fact that the sum of all electron energies that exit the organ is statistically equal with the sum of all electron energies that enter in that particular organ. In this version of program, it is considered the following interactions: the Rayleigh scattering, the Compton scattering and the photoelectric effect. The Compton scattering is modeled by several methods which avoid the solving of Klein-Nishina equation namely 'classic', Kahn, Wielopolski and E.G.S. (taken from Electron Gamma Shower source code) algorithm. A preliminary study for angular distribution by applying all of these algorithms has been made. The best results is provided by the E.G.S.-based algorithm followed by the Kahn and the 'classic' one. The patient doses computed by applying Kahn or 'classic' algorithms are in good agreement with data from literature or with data generated by other similar Pc programs, and the small differences could be explained by the fact that different kind of mathematical phantoms have been used. Also, we can conclude that all these comparison data were based on Kahn or 'classic' algorithms for modeling the Compton scattering. In spite of these, the usage of E.G.S. based algorithm is strongly recommended. With this algorithm it was obtained smaller patient doses for several kind of radiological examinations. (authors)}
place = {France}
year = {2006}
month = {Jul}
}