Energy measurements in a prototype proton CT scanner

Abstract

In proton treatment planning, the use of protons instead of X-rays for computerized tomography (CT) studies has potential advantages, especially for medical applications. Proton CT requires accurate measurement of the energy loss of protons passing through the object. The resolution of a proton CT scanner is determined by the resolution of the energy loss measurement, which is limited by the inherent energy straggling of protons. An experiment with a doped CsI(Tl) crystal was designed to determine the resolution of the energy loss measurement of protons in the energy range from 40 MeV to 250 MeV experimentally. It was found that, in principle, the resolution of a proton calorimeter is adequate to CT studies with objects of realistic size. © 2007 American Institute of Physics.