Proton Computed Tomography Image Reconstruction Based on the Richardson-Lucy Algorithm

Abstract

Proton therapy is an emerging method in cancer therapy. One of the main developments is to increase the accuracy of the Bragg-peak position calculation, which requires more precise relative stopping power (RSP) measurements. A promising choice is the application of proton computed tomography (pCT) systems which takes the images under similar conditions, as they use the same irradiation device and hadron beam for imaging and treatment. A key aim is to develop a precise image reconstruction algorithm for pCT systems to reach their maximal performance. In this work, an iterative image reconstruction algorithm, based on the Richardson-Lucy iteration is proposed for the first time for proton CT image reconstruction. Monte Carlo (MC) simulations of CTP528 and CTP404 phantoms were used to benchmark the proposed method. In the case of an idealized detector setup, using a 1 mm pitch grid, 4.88 lp/cm spatial resolution and 0.66% average RSP uncertainty was achieved. The present method provides a promising proof-of-concept candidate for compromise between accuracy and speed with several further development directions.