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While providing good time\u2010of\u2010flight performance, this design limits the spatial resolution and causes radial astigmatism as the depth\u2010of\u2010interaction (DOI) remains unknown.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Purpose<\/jats:title>\n                    <jats:p>We propose an alternative, aiming to combine the advantages of current detectors with the DOI capabilities shown for monolithic concepts, based on semi\u2010monolithic scintillators (slabs). Here, the optical photons spread along one dimension enabling DOI\u2010encoding with a still small readout area beneficial for timing performance.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      An array of eight monolithic LYSO slabs of dimensions 3.9\u00a0\u00d7\u00a032\u00a0\u00d7\u00a019\u00a0mm\n                      <jats:sup>3<\/jats:sup>\n                      was read out by a 64\u2010channel photosensor containing digital SiPMs (DPC3200\u201022\u201044, Philips Digital Photon Counting). The position estimation in the detector's monolithic and DOI direction was based on a calibration with a fan beam collimator and the machine learning technique gradient tree boosting (GTB).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>We achieved a positioning performance in terms of mean absolute error (MAE) of 1.44\u00a0mm for the monolithic direction and 2.12\u00a0mm for DOI considering a wide energy window of 300\u2013700\u00a0keV. The energy resolution was determined to be 11.3%, applying a positional\u2010dependent energy calibration.<\/jats:p>\n                    <jats:p>We established both an analytical and machine\u2010learning\u2010based timing calibration approach and applied them for a first\u2010photon trigger. The analytical timing calibration corrects for electronic and optical time skews leading to 240\u00a0ps coincidence resolving time (CRT) for a pair of slab\u2010detectors. The CRT was significantly improved by utilizing GTB to predict the time difference based on specific training data and applied on top of the analytical calibration. We achieved 209\u00a0ps for the wide energy window and 198\u00a0ps for a narrow selection around the photopeak (411\u2013561\u00a0keV). To maintain the detector's sensitivity, no filters were applied to the data during processing.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Overall, the semi\u2010monolithic detector provides attractive performance characteristics. Especially, a good CRT can be achieved while introducing DOI capabilities to the detector, making the concept suitable for clinical PET scanners.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1002\/mp.16015","type":"journal-article","created":{"date-parts":[[2022,10,19]],"date-time":"2022-10-19T03:54:38Z","timestamp":1666151678000},"page":"7469-7488","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":50,"title":["A semi\u2010monolithic detector providing intrinsic DOI\u2010encoding and sub\u2010200\u00a0ps CRT TOF\u2010capabilities for clinical PET applications"],"prefix":"10.1002","volume":"49","author":[{"given":"Florian","family":"Mueller","sequence":"first","affiliation":[{"name":"Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University  Aachen Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stephan","family":"Naunheim","sequence":"additional","affiliation":[{"name":"Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University  Aachen Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yannick","family":"Kuhl","sequence":"additional","affiliation":[{"name":"Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University  Aachen Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David","family":"Schug","sequence":"additional","affiliation":[{"name":"Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University  Aachen Germany"},{"name":"Hyperion Hybrid Imaging Systems GmbH  Aachen Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Torsten","family":"Solf","sequence":"additional","affiliation":[{"name":"Philips Digital Photon Counting (PDPC)  Aachen Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Volkmar","family":"Schulz","sequence":"additional","affiliation":[{"name":"Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University  Aachen Germany"},{"name":"Hyperion Hybrid Imaging Systems GmbH  Aachen Germany"},{"name":"Fraunhofer Institute for Digital Medicine MEVIS  Aachen Germany"},{"name":"III. 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