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Table 1 System specification and performance parameters of the Siemens HRRT and GE SIGNA PET/MR system

From: Cross-validation study between the HRRT and the PET component of the SIGNA PET/MRI system with focus on neuroimaging

  HRRT SIGNA PET/MR
Crystal material LSO/LYSO Lutetium based
Crystal dimensions [mm3] 2.44 × 2.44 × 10 4.0 × 5.3 × 25
Number of crystals 119,808 20,160
Detector PMTs Si-PM
FOV (axial vs. transaxial) [cm] 25.2 x 31.2 25 × 60
Reported resolution (radial × tangential × axial) [mm] 2.3 × 2.3 × 2.5a [7, 12] 3.48 × 3.43 × 4.67b [8]
Reported sensitivity 2.9%c [12] 23.3 cps/kBqd [8]
Special characteristics DOI correction TOF (timing resolution < 400 ps), simultaneous PET/MRI
  1. aAt 1 cm tangential offset to the center of the FOV (reconstructed with a 3D ordinary Poisson-ordered subset expectation-maximization algorithm (OP-OSEM))
  2. bAt 1 cm tangential offset to the center of the FOV (reconstructed with a TOF OSEM algorithm with filter)
  3. cAt the center FOV based on the NEMA 2001 evaluation protocol; note that measured activity was normalized by the line source length in the scanner FOV (25 cm), rather than its entire length (70 cm)
  4. dAt the center FOV based on the NEMA 2012 evaluation protocol. Sensitivity of 23.3 cps/kBq is equivalent to 2.3%. When expressed in the same units as the sensitivity measured for the HRRT, the GE SIGNA sensitivity is estimated to be 6.5%