@misc{oai:repo.qst.go.jp:00083757,
 author = {Hideaki, Tashima and Go, Akamatsu and Taichi, Yamashita and Taiga, Yamaya and Hideaki, Tashima and Go, Akamatsu and Taichi, Yamashita and Taiga, Yamaya},
 month = {Oct},
 note = {Scatter correction is essential for quantitative PET imaging. The current standard method corrects the scatter effect on each measured data bin in the projection domain with a scatter component estimated by model-based scatter simulation. However, the scatter components are not calculated for all the data bins due to the computational burden. Instead, coarsely sampled data bins are interpolated for each measured data bin. In our helmet-type PET, the interpolation for the hemispherical arrangement of block detectors is complex compared with conventional cylindrical PET scanners with large gantry bore diameters. Therefore, we propose an image domain scatter correction method to avoid interpolating data in the projection domain to improve correction accuracy. We modeled an uncorrected image as the sum of a radioactivity image and a scatter image. The proposed method alternatively updates the uncorrected radioactivity image and the scatter image. To update the scatter image, we first reconstructed a coarsely sampled scatter image from coarsely sampled scatter components estimated by model-based scatter simulation with a radioactivity image generated by subtracting the latest scatter image from the latest uncorrected image. Then the coarsely sampled scatter image was up-sampled to a fully sampled scatter image. Finally, we obtained a scatter corrected image by subtracting the latest scatter image from the latest uncorrected radioactivity image. We implemented the proposed method with the list-mode OSEM and the single scatter simulation for the time-of-flight helmet-type PET prototype. An experiment with the Hoffman brain phantom showed that the proposed method improved the gray matter to white matter contrast from 45% to 51% compared with the conventional correction method with projection domain interpolation., IEEE NSS MIC 2021},
 title = {Development of Scatter Correction with Image-domain Interpolation for TOF Helmet-type PET},
 year = {2021}
}