Print Email Facebook Twitter Optimizing modelling in iterative image reconstruction for preclinical pinhole PET Title Optimizing modelling in iterative image reconstruction for preclinical pinhole PET Author Goorden, M.C. (TU Delft RST/Biomedical Imaging) van Roosmalen, J. (TU Delft RST/Biomedical Imaging) van der Have, F. (TU Delft RST/Biomedical Imaging; MILabs B.V.) Beekman, F.J. (TU Delft RST/Biomedical Imaging; MILabs B.V.; University Medical Center Utrecht) Date 2016-04-19 Abstract The recently developed versatile emission computed tomography (VECTor) technology enables high-energy SPECT and simultaneous SPECT and PET of small animals at sub-mm resolutions. VECTor uses dedicated clustered pinhole collimators mounted in a scanner with three stationary large-area NaI(Tl) gamma detectors. Here, we develop and validate dedicated image reconstruction methods that compensate for image degradation by incorporating accurate models for the transport of high-energy annihilation gamma photons. Ray tracing software was used to calculate photon transport through the collimator structures and into the gamma detector. Input to this code are several geometric parameters estimated from system calibration with a scanning 99mTc point source. Effects on reconstructed images of (i) modelling variable depth-of-interaction (DOI) in the detector, (ii) incorporating photon paths that go through multiple pinholes ('multiple-pinhole paths' (MPP)), and (iii) including various amounts of point spread function (PSF) tail were evaluated. Imaging 18F in resolution and uniformity phantoms showed that including large parts of PSFs is essential to obtain good contrast-noise characteristics and that DOI modelling is highly effective in removing deformations of small structures, together leading to 0.75 mm resolution PET images of a hot-rod Derenzo phantom. Moreover, MPP modelling reduced the level of background noise. These improvements were also clearly visible in mouse images. Performance of VECTor can thus be significantly improved by accurately modelling annihilation gamma photon transport. Subject image reconstructionpositron emission tomography (PET)single photon emission computed tomography (SPECT) To reference this document use: http://resolver.tudelft.nl/uuid:3c0270ba-1595-4b74-9300-35026becf912 DOI https://doi.org/10.1088/0031-9155/61/10/3712 Embargo date 2017-04-19 ISSN 0031-9155 Source Physics in Medicine and Biology, 61 (10), 3712-3733 Part of collection Institutional Repository Document type journal article Rights © 2016 M.C. Goorden, J. van Roosmalen, F. van der Have, F.J. Beekman Files PDF reconpaper_final.pdf 1.32 MB Close viewer /islandora/object/uuid:3c0270ba-1595-4b74-9300-35026becf912/datastream/OBJ/view