Advances in Calibration and Data-Processing for a clinical semi-monolithic DOI-capable PET Detector reaching sub-200 ps Timing Resolution

Abstract

Total- and Whole-Body-PET scanners utilize numerous detectors introducing further challenges besides spatial, energy, and time resolution, such as fast calibration and cost-efficiency. Semi-monolithic detectors (called slabs) combine the advantages of pixelated and monolithic scintillators, providing intrinsic depth-of-interaction (DOI) capabilities, high density of optical photons as well as reduced dead time at a competitive cost compared to classical segmented arrays. Here, we present recent advances made in the different aspects of detector calibration and data processing. An array of 8 monolithic LYSO slabs of dimensions 3.9 x 32 x 19 mm3was coupled to a 64-channel photosensor array based on digital SiPMs (DPC 3200-22-44). Positioning calibration was performed using the supervised ML algorithm gradient tree boosting (GTB) and a fan beam collimator with multiple simultaneous irradiations allowing for fast calibration routines. The timing calibration includes an analytical correction of the detector time skews following GTB-based improvements. We achieved a spatial resolution in terms of mean absolute error (MAE) of 1.22 mm in planar and 1.86 mm in DOI direction, a coincidence resolution time (CRT) of 186 ps, and an energy resolution of 11.3%. The performance is better than or comparable to currently established clinical detectors following a segmented design concept. We put a special focus on the easy and fast applicability of the calibration methods to demonstrate a pathway for the broad translation of slab-based detectors into clinical PET systems.

Authors 7

1. Florian Mueller Aachen Institute for Experimental Molecular Imaging Department of Physics of Molecular Imaging Systems

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University,Institute for Experimental Molecular Imaging,Department of Physics of Molecular Imaging Systems,Aachen,North Rhine-Westphalia,Germany

   Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen, North Rhine-Westphalia, Germany

2. Yannick Kuhl Aachen Institute for Experimental Molecular Imaging Department of Physics of Molecular Imaging Systems

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University,Institute for Experimental Molecular Imaging,Department of Physics of Molecular Imaging Systems,Aachen,North Rhine-Westphalia,Germany

   Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen, North Rhine-Westphalia, Germany

3. Stephan Naunheim Aachen Institute for Experimental Molecular Imaging Department of Physics of Molecular Imaging Systems

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University,Institute for Experimental Molecular Imaging,Department of Physics of Molecular Imaging Systems,Aachen,North Rhine-Westphalia,Germany

   Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen, North Rhine-Westphalia, Germany

4. M. Bovelett Aachen Institute for Experimental Molecular Imaging Department of Physics of Molecular Imaging Systems

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University,Institute for Experimental Molecular Imaging,Department of Physics of Molecular Imaging Systems,Aachen,North Rhine-Westphalia,Germany

   Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen, North Rhine-Westphalia, Germany

5. T.-M. Mai Aachen Institute for Experimental Molecular Imaging Department of Physics of Molecular Imaging Systems

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University,Institute for Experimental Molecular Imaging,Department of Physics of Molecular Imaging Systems,Aachen,North Rhine-Westphalia,Germany

   Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen, North Rhine-Westphalia, Germany

6. David Schug Aachen Institute for Experimental Molecular Imaging Department of Physics of Molecular Imaging Systems

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University,Institute for Experimental Molecular Imaging,Department of Physics of Molecular Imaging Systems,Aachen,North Rhine-Westphalia,Germany

   Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen, North Rhine-Westphalia, Germany

   Hyperion Hybrid Imaging System, Aachen, North Rhine-Westphalia, Germany

7. Volkmar Schulz Aachen Institute for Experimental Molecular Imaging Department of Physics of Molecular Imaging Systems

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University,Institute for Experimental Molecular Imaging,Department of Physics of Molecular Imaging Systems,Aachen,North Rhine-Westphalia,Germany

   Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen, North Rhine-Westphalia, Germany

   Hyperion Hybrid Imaging System, Aachen, North Rhine-Westphalia, Germany