title: Image Quality and Diagnostic Performance of a Digital PET Prototype in Patients with Oncologic Diseases: Initial Experience and Comparison with Analog PET.
abstract: We report our initial clinical experience for image quality and diagnostic performance of a digital PET prototype scanner with time-of-flight (DigitalTF), compared with an analog PET scanner with time-of-flight (GeminiTF PET/CT).
  
  
  METHODS
  Twenty-one oncologic patients, mean age 58 y, first underwent clinical (18)F-FDG PET/CT on the GeminiTF. The scanner table was then withdrawn while the patient remained on the table, and the DigitalTF was inserted between the GeminiTF PET and CT scanner. The patients were scanned for a second time using the same PET field of view with CT from the GeminiTF for attenuation correction. Two interpreters reviewed the 2 sets of PET/CT images for overall image quality, lesion conspicuity, and sharpness. They counted the number of suggestive (18)F-FDG-avid lesions and provided the TNM staging for the 5 patients referred for initial staging. Standardized uptake values (SUVs) and SUV gradients as a measure of lesion sharpness were obtained.
  
  
  RESULTS
  The DigitalTF showed better image quality than the GeminiTF. In a side-by-side comparison using a 5-point scale, lesion conspicuity (4.3 ± 0.6), lesion sharpness (4.3 ± 0.6), and diagnostic confidence (3.4 ± 0.7) were better with DigitalTF than with GeminiTF (P < 0.01). In 52 representative lesions, the lesion maximum SUV was 36% higher with DigitalTF than with GeminiTF, lesion-to-blood-pool SUV ratio was 59% higher, and SUV gradient was 51% higher, with good correlation between the 2 scanners. Lesions less than 1.5 cm showed a greater increase in SUV from GeminiTF to DigitalTF than those lesions 1.5 cm or greater. In 5 of 21 patients, DigitalTF showed an additional 8 suggestive lesions that were not seen using GeminiTF. In the 15 restaging patients, the true-negative rate was 100% and true-positive rate was 78% for both scanners. In the 5 patients for initial staging, DigitalTF led to upstaging in 2 patients and showed the same staging in the other 3 patients, compared with GeminiTF.
  
  
  CONCLUSIONS
  DigitalTF provides better image quality, diagnostic confidence, and accuracy than GeminiTF. DigitalTF may be the most beneficial in detecting small tumor lesions and disease staging.
authors.affiliation: Department of Radiology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio Peter.Faulhaber@UHhospitals.org nguyennc@upmc.edu.
authors.forename: Nghi C
authors.initials: NC
authors.lastname: Nguyen
authors.affiliation: Department of Radiology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio.
authors.forename: Jose L
authors.initials: JL
authors.lastname: Vercher-Conejero
authors.affiliation: Epidemiology and Biostatistics, School of Medicine, Case Western Reserve University, Cleveland, Ohio; and.
authors.forename: Abdus
authors.initials: A
authors.lastname: Sattar
authors.affiliation: Philips Healthcare, Advanced Molecular Imaging, Cleveland, Ohio.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Miller
authors.affiliation: Philips Healthcare, Advanced Molecular Imaging, Cleveland, Ohio.
authors.forename: Piotr J
authors.initials: PJ
authors.lastname: Maniawski
authors.affiliation: Department of Radiology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio.
authors.forename: David W
authors.initials: DW
authors.lastname: Jordan
authors.affiliation: Department of Radiology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio.
authors.forename: Raymond F
authors.initials: RF
authors.lastname: Muzic
authors.affiliation: Department of Radiology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio.
authors.forename: Kuan-Hao
authors.initials: KH
authors.lastname: Su
authors.affiliation: Department of Radiology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio.
authors.forename: James K
authors.initials: JK
authors.lastname: O'Donnell
authors.affiliation: Department of Radiology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio Peter.Faulhaber@UHhospitals.org nguyennc@upmc.edu.
authors.forename: Peter F
authors.initials: PF
authors.lastname: Faulhaber
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation*; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000000981:diagnostic imaging*; D010865:Pilot Projects; D049268:Positron-Emission Tomography / Q000295:instrumentation* / Q000379:methods; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*
keywords: 18F-FDG PET; digital PET; direct photon counting; oncology