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Proton computed tomography as a tool for proton therapy planning: preliminary computer simulations and comparisons with x‐ray CT basics
Author(s) -
Teixeira de Assis Joaquim,
Yevseyeva, Olga,
Evseev Ivan,
Lopes Ricardo Tadeu,
Schelin Hugo Reuters,
Loss Klock Márgio Cezar,
Paschuk Sergei A.,
Schulte Reinhard W.,
Williams David C.
Publication year - 2005
Publication title -
x‐ray spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.447
H-Index - 45
eISSN - 1097-4539
pISSN - 0049-8246
DOI - 10.1002/xrs.869
Subject(s) - proton therapy , proton , bragg peak , tomography , medical physics , physics , radiation treatment planning , computed tomography , nuclear medicine , computational physics , computer science , optics , nuclear physics , radiology , medicine , radiation therapy
Proton beams can destroy tumors better than other radiation treatment options because they deliver their energy in a very accurate way, while leaving the surrounding tissue undamaged. However, it requires a very accurate prediction of the Bragg peak position within the patient's body. In existing proton treatment centers, the dose calculations are performed based on x‐ray computed tomography (CT) and the patient is positioned with x‐ray radiographs. During the 1970s and early 1980s, it was shown that the use of proton beams rather than conventional x‐rays could have some advantages. With the development of specialized medical proton gantries at Loma Linda University Medical Center (USA) and several other proton treatment centers worldwide, interest in this question has been renewed. The modern approach has advanced from simple proton film radiography to CT reconstructions from proton energy loss measurements employing individual proton tracking techniques. This permits image degradation due to multiple Coulomb scattering, one of the main problems of proton CT, to be reduced. Current work is devoted to the comparison of conventional x‐ray CT and proton computed tomography (pCT) as two alternative tools for measuring the physical properties of the human body, required for proton treatment planning. In this paper, a brief comparative overview of the physical basics of both methods are followed by the analysis of Monte Carlo simulation results. The first‐generation CT scheme was assumed for simplicity. The precisions relative to water volumetric electron density distributions, extracted from CT and pCT images, and the sources of absolute errors are discussed. Copyright © 2005 John Wiley & Sons, Ltd.