Design of a proton computed tomography system for applications in proton radiation therapy

The most likely path of an energetic charged particle through a uniform medium

“…A conceptual design (Schulte et al 2003) of a pCT imaging device is shown in figure 1. The purpose of such a device is to measure both the entrance and exit angles and positions of individual protons, along with the exit energy.…”

“…Higher momentum protons deposite less energy into the patient resulting in lower dosage. The optimal energy may not be known until prototype pCT devices can be tested, although kinetic energies between 200 and 250 MeV have been suggested for imaging of humans (Schulte et al 2003, Hanson et al 1982.…”

“…Reasonable goals for the accuracy of a pCT image for the purposes of hadron treatment planning is a spacial granularity of 1 mm and a density resolution of 1% (Schulte et al 2003). It will be difficult to achieve the former goal if the trajectory of protons in the patient cannot be predicted within this accuracy.…”

Development of a head scanner for proton CT

“…by measuring the residual range of protons of higher energy than those stopping in the patient. We presented the requirements for pCT in 2002 [1], and proposed in 2003 a detector system [2], which incorporated the basic building blocks of a pCT system: a tracker to measure the proton path before and after the phantom, and allows to calculate the Most Likely Path (MLP) the proton has taken within the phantom [3], and an energy detector to measure the residual energy or range of the proton, which is used to calculate the Water Equivalent Path Length (WEPL) in the phantom.…”

General purpose graphics processing unit speedup of integral relative electron density calculation for proton computed tomography

“…Despite these advantages, a fully operational pCT system does currently not exist, in part, related to the large amount of proton and object data that need to be acquired and reconstructed, respectively. Preliminary work in proton CT over the last several years has centered on the most likely path formalism [8], image reconstruction [6], [3], [4], [5], and basic design of a system [7]. A vital step in the reconstruction of a pCT image is the calculation of the integral relative electron densities, which must be known for each of the proton histories.…”