Toward proton computed tomography

Proton therapy, long regarded as a superior method of radiation therapy, is now becoming more cost effective and is being used in a number of clinical centers around the world. In light of this development the use of the proton beam itself should be considered for the most accurate method of treatment planning. X-ray computed tomography (XCT), which is widely available, has been used for the treatment planning for proton therapy. The basic interactions of XCT in matter are fundamentally different than those of the protons. Thus, the resulting density map from XCT is only an approximation of the true density map for proton therapy. Progress in proton computed tomography (pCT) is presented in this work. The experimental requirements for pCT are examined, and data analysis and Monte Carlo simulations are used to estimate the feasibility of pCT as an imaging modality.