title: Performance comparison of high quantum efficiency and normal quantum efficiency photomultiplier tubes and position sensitive photomultiplier tubes for high resolution PET and SPECT detectors.
abstract: OBJECTIVE
  Recently, photomultiplier tubes (PMTs) and position sensitive PMTs (PSPMTs) with higher quantum efficiencies (HQE) have been developed. However, it remains unclear whether they actually improve such performances as the energy and spatial resolution for PET and SPECT detectors.
  
  
  METHODS
  The authors evaluated the quantum efficiencies (QEs) for PMTs and PSPMTs and measured the energy resolution of a 3-in. round HQE PMT combined with various scintillators and compared the results with a conventional normal quantum efficiency (NQE) PMT of the same type. The authors also measured the position and energy performance of a 2-in. square HQE PSPMT combined with scintillator blocks and compared them with a NQE PSPMT of the same size.
  
  
  RESULTS
  The energy resolution of the 3-in. round HQE PMT showed higher energy resolution than the NQE with all scintillators. The improvement of the energy resolution was smaller, for all measurements, than the expected value from the quantum efficiency of the PMT but was higher for the scintillators with smaller light outputs. The energy and position performance of the HQE PSPMT based block detectors showed higher position and energy performance than those with NQE.
  
  
  CONCLUSIONS
  From these results, the authors conclude that both HQE PMT and PSPMT contribute to improve the energy and position performance for PET and SPECT detectors. Significant performance improvements will be expected in PET and SPECT systems by the use of the HQE PMTs or PSPMTs.
authors.affiliation: Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan. s-yama@met.nagoya-u.ac.jp
authors.forename: Seiichi
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Watabe
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Kato
authors.forename: Jun
authors.initials: J
authors.lastname: Hatazawa
mesh_terms: D005720:Gamma Rays; D017785:Photons; D049268:Positron-Emission Tomography / Q000295:instrumentation*; D012588:Scintillation Counting / Q000295:instrumentation*; D015899:Tomography, Emission-Computed, Single-Photon / Q000295:instrumentation*