title: A combined time-of-flight and depth-of-interaction detector for total-body positron emission tomography.
abstract: OBJECTIVE
  In support of a project to build a total-body PET scanner with an axial field-of-view of 2 m, the authors are developing simple, cost-effective block detectors with combined time-of-flight (TOF) and depth-of-interaction (DOI) capabilities.
  
  
  METHODS
  This work focuses on investigating the potential of phosphor-coated crystals with conventional PMT-based block detector readout to provide DOI information while preserving timing resolution. The authors explored a variety of phosphor-coating configurations with single crystals and crystal arrays. Several pulse shape discrimination techniques were investigated, including decay time, delayed charge integration (DCI), and average signal shapes.
  
  
  RESULTS
  Pulse shape discrimination based on DCI provided the lowest DOI positioning error: 2 mm DOI positioning error was obtained with single phosphor-coated crystals while 3-3.5 mm DOI error was measured with the block detector module. Minimal timing resolution degradation was observed with single phosphor-coated crystals compared to uncoated crystals, and a timing resolution of 442 ps was obtained with phosphor-coated crystals in the block detector compared to 404 ps without phosphor coating. Flood maps showed a slight degradation in crystal resolvability with phosphor-coated crystals; however, all crystals could be resolved. Energy resolution was degraded by 3%-7% with phosphor-coated crystals compared to uncoated crystals.
  
  
  CONCLUSIONS
  These results demonstrate the feasibility of obtaining TOF-DOI capabilities with simple block detector readout using phosphor-coated crystals.
authors: Department of Biomedical Engineering, University of California, Davis, One Shields Avenue, Davis, California 95616.
authors: Eric
authors: E
authors: Berg
authors: Department of Biomedical Engineering, University of California, Davis, One Shields Avenue, Davis, California 95616.
authors: Emilie
authors: E
authors: Roncali
authors: Molecular Imaging, Siemens Healthcare, Knoxville, Tennessee 37932.
authors: Maciej
authors: M
authors: Kapusta
authors: Department of Biomedical Engineering, University of California, Davis, One Shields Avenue, Davis, California 95616.
authors: Junwei
authors: J
authors: Du
authors: Department of Biomedical Engineering, University of California, Davis, One Shields Avenue, Davis, California 95616.
authors: Simon R
authors: SR
authors: Cherry
mesh_terms: D003362:Cost-Benefit Analysis; D049268:Positron-Emission Tomography / Q000191:economics / Q000295:instrumentation*; D059629:Signal-To-Noise Ratio; D013997:Time Factors; D051598:Whole Body Imaging / Q000191:economics / Q000295:instrumentation*