title: Performance of a whole-body PET scanner using curve-plate NaI(Tl) detectors.
abstract: A whole-body PET scanner, without interplane septa, has been designed to achieve high performance in clinical applications. The C-PET scanner, an advancement of the PENN PET scanners, is unique in the use of 6 curved NaI(Tl) detectors (2.54 cm thick). The scanner has a ring diameter of 90 cm, a patient port diameter of 56 cm, and an axial field of view of 25.6 cm. A (137)Cs point source is used for transmission scans.
  
  
  METHODS
  Following the protocols of the International Electrotechnical Commission ([IEC] 61675-1) and the National Electrical Manufacturers Association ([NEMA] NU-2-1994 and an updated version, NU2-2001), point and line sources, as well as uniform cylinders, were used to determine the performance characteristics of the C-PET scanner. An image-quality phantom and patient data were used to evaluate image quality under clinical scanning conditions. Data were rebinned with Fourier rebinning into 2-dimensional (slice-oriented) datasets and reconstructed with an iterative reconstruction algorithm.
  
  
  RESULTS
  The spatial resolution for a point source in the transaxial direction was 4.6 mm (full width at half maximum) at the center, and the axial resolution was 5.7 mm. For the NU2-1994 analysis, the sensitivity was 12.7 cps/Bq/mL (444 kcps/microCi/mL), the scatter fraction was 25%, and the peak noise equivalent count rate (NEC) for a uniform cylinder (diameter = 20 cm, length = 19 cm) was 49 kcps at an activity concentration of 11.2 kBq/mL. For the IEC protocol, the peak NEC was 41 kcps at 12.3 kBq/mL, and for the NU2-2001 protocol, the peak NEC was 14 kcps at 3.8 kBq/mL. The NU2-2001 NEC value differed significantly because of differences in the data analysis and the use of a 70-cm-long phantom.
  
  
  CONCLUSIONS
  Compared with previous PENN PET scanners, the C-PET, with its curved detectors and improvements in pulse shaping, integration dead time, and triggering, has an improved count-rate capability and spatial resolution. With the refinements in the singles transmission technique and iterative reconstruction, image quality is improved and scan time is shortened. With single-event transmission scans interleaved between sequential emission scans, a whole-body study can be completed in <1 h. Overall, C-PET is a cost-effective PET scanner that performs well in a broad variety of clinical applications.
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: L E
authors.initials: LE
authors.lastname: Adam
authors.forename: J S
authors.initials: JS
authors.lastname: Karp
authors.forename: M E
authors.initials: ME
authors.lastname: Daube-Witherspoon
authors.forename: R J
authors.initials: RJ
authors.lastname: Smith
mesh_terms: D000328:Adult; D004867:Equipment Design; D005260:Female; D006689:Hodgkin Disease / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted; D019047:Phantoms, Imaging; D012974:Sodium Iodide; D013793:Thallium; D014055:Tomography, Emission-Computed / Q000295:instrumentation*
chemical_list: D013793:Thallium; D012974:Sodium Iodide