学术文献库

Objective: 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. An excellent 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 an precise image reconstruction algorithm for pCT systems to reach their maximal performance. Approach: An image reconstruction algorithm was developed in this work, which is suitable to reconstruct pCT images from the deposited energy, position and direction measurement of individual protons. The flexibility of an iterative image reconstruction algorithm was utilised to appropriately model the trajectory of protons. Monte Carlo (MC) simulations of a Derenzo and a CTP404 phantom was used to test the accuracy of the image reconstruction. Main results: The Richardson-Lucy algorithm was applied first and successfully for pCT image reconstruction. Authors used an averaged probability density based approach for the interaction (system) matrix generation, which is a relevant description to consider the uncertainty of the path of the protons in the patient. In case of an idealized setup, 1.43 lp/cm spatial resolution and 0.3% RSP accuracy was achieved. Significance: This work is the first application of the Richardson-Lucy algorithm, for pCT image reconstruction.