PSF reconstruction for Compton-based prompt gamma imaging.

In this study, we investigate the performance of the list-mode ordered subset expectation maximization algorithm with a shift-variant point spread function model (LM-OSEM-SV-PSF). We also evaluate how well the PG images reconstructed using a SV-PSF model reproduce the distal falloff of the proton beam. SV-PSF parameters were estimated by simulation data of point sources at various positions. Simulated PGs were produced in a water phantom irradiated with a proton beam. Compared to the LM-OSEM algorithm, the LM-OSEM-SV-PSF algorithm improved the quality of the reconstructed PG images and the estimation of PG falloff positions. In addition, the 4.44 and 5.25 MeV PG emissions can be accurately reconstructed using the LM-OSEM-SV-PSF algorithm. However, for the 2.31 and 6.13 MeV PG emissions, the LM-OSEM-SV-PSF reconstruction provides limited improvement. We also found that the LM-OSEM algorithm followed by a shift-variant Richardson-Lucy deconvolution could reconstruct images with quality visually similar to the LM-OSEM-SV-PSF reconstructed images while requiring shorter computation time. PMID: 29189207 [PubMed - as supplied by publisher]
Source: Physics in Medicine and Biology - Category: Physics Authors: Tags: Phys Med Biol Source Type: research