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Proceedings Paper

The density measurements in pCT imaging
Author(s): Ivan Evseev; Joaquim Teixeira de Assis; Olga Yevseyeva; Hugo Reuters Schelin; Margio Cezar Loss Klock; Joao Antonio Palma Setti; Ricardo Tadeu Lopes; Ubirajara Maribondo Vinagre Filho; Reinhard W. Schulte; David C. Williams
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Paper Abstract

In existing proton treatment centers, dose calculations are performed based on x-ray computerized tomography (CT). Alternatively, the therapeutic proton beam could be used to collect the data for treatment planning via proton CT (pCT). With the development of medical proton gantries, first at Loma Linda University Medical Center and now in several other proton treatment centers, it is of interest to continue the early pCT investigations of the 1970s and the early 1980s. From that time, the basic idea of the pCT method has advanced from average energy loss measurements to an individual proton tracking technique. This reduces the image degradation due to multiple Coulomb scattering. Thereby, the central pCT problem shifts to the fidelity of the physical information obtained about the scanned patient, which will be used for proton treatment planning. The accuracy of relative electron density distributions extracted from pCT images was investigated in this work using continuous slowing down approximation (CSDA) and water-equivalent-thickness (WET) concepts. Analytical results were checked against Monte Carlo simulations, which were obtained with SRIM2003 and GEANT4 Monte Carlo software packages. The range of applications and the sources of absolute errors are discussed.

Paper Details

Date Published: 20 April 2005
PDF: 11 pages
Proc. SPIE 5745, Medical Imaging 2005: Physics of Medical Imaging, (20 April 2005); doi: 10.1117/12.595720
Show Author Affiliations
Ivan Evseev, Polytechnic Institute/State Univ. of Rio de Janeiro (Brazil)
Joaquim Teixeira de Assis, Polytechnic Institute/State Univ. of Rio de Janeiro (Brazil)
Olga Yevseyeva, Polytechnic Institute/State Univ. of Rio de Janeiro (Brazil)
Hugo Reuters Schelin, CEFET-PR (Brazil)
Margio Cezar Loss Klock, CEFET-PR (Brazil)
Joao Antonio Palma Setti, CEFET-PR (Brazil)
Ricardo Tadeu Lopes, Federal Univ. of Rio de Janeiro (Brazil)
Ubirajara Maribondo Vinagre Filho, Institute of Nuclear Engineering (Brazil)
Reinhard W. Schulte, Loma Linda Univ. Medical Ctr. (United States)
David C. Williams, Univ. of California/Santa Cruz (United States)

Published in SPIE Proceedings Vol. 5745:
Medical Imaging 2005: Physics of Medical Imaging
Michael J. Flynn, Editor(s)

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