Integration of Proton Computed Tomography into the Open Source Software STIR

Abstract

Proton computed tomography (pCT) offers unique image formation attributes, with a potential for increasing accuracy of treatment planning in proton beam therapy. To maximize the potential of pCT it is necessary to develop advanced reconstruction algorithms that can accurately recover relative proton stopping power maps. This study aims to integrate pCT into STIR (Software for Tomographic Image Reconstruction), a popular Multi-Platform Object-Oriented framework for reconstruction in tomographic imaging to benefit from its software infrastructure. Open source STIR library is currently suitable for reconstructing and manipulating data from Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT), which are based on cylindrical scanner geometries. Although pCT has a noncylindrical geometry, STIR provides the framework for single event detection and modelling of the proton interactions. This initial implementation includes classes and functions with new features such as general proton scanner geometry, binning of list mode proton data into sinograms and uses analytical reconstruction algorithms already available in STIR. The structure of the new implemented features is discussed. Future work will include additional components to establish STIR as a potential toolkit for pCT image reconstruction.