Proton computed tomography using multichannel gas detection technology

A method for creating tomographic images of a target Proton Computed Tomography (pCT), comprising:

• directing a stream of protons toward a target;
• measuring the proton trajectory of each proton before the target with a pre-tracker;
• measuring the proton trajectory of each proton after the target with a post-tracker;
• positioning a gaseous Time Projection Chamber (TPC) having a plurality of gas cells after the trackers to measure the proton energy after exiting the target by amplifying and measuring the profile of energy deposited along the proton trajectory through the TPC via the signal from ionization electrons liberated from proton energy loss in each gas cell;
• a variable energy degrading shutter between the post-tracker and the TPC, said shutter extending the dynamic range of the TPC and maintaining good energy resolution in the TPC;
• said shutter including a shutter encoder;
• recording data from the shutter encoder in the data stream for automatic correction of the energy loss in the shutter;
• and
• determining the proton energy by a search algorithm to determine the best match for the energy loss profile along the proton trajectory (dE/dx), with the stopping energy as the seed value for the search range.