title: Multicenter harmonization of 89Zr PET/CT performance.
abstract: This study investigated the feasibility of quantitative accuracy and harmonized image quality in (89)Zr-PET/CT multicenter studies.
  
  
  METHODS
  Five PET/CT scanners from 3 vendors were included. (89)Zr activity was measured in a central dose calibrator before delivery. Local activity assays were based on volume as well as on the local dose calibrator. Accuracy and image noise were determined from a cross calibration experiment. Image quality was assessed from recovery coefficients derived from different volume-of-interest (VOI) methods (VOI A 50%, based on a 3-dimensional isocontour at 50% of the maximum voxel value with local background correction; VOI Max, based on the voxel with the highest uptake; and VOI 3Dpeak, based on a spheric VOI of 1.2-cm diameter positioned so as to maximize the enclosed average). PET images were analyzed before and after postreconstruction smoothing, applied to match image noise.
  
  
  RESULTS
  PET/CT accuracy and image noise ranged from -3% to 10% and from 13% to 22%, respectively. VOI 3Dpeak produced the most reproducible recovery coefficients. After calibration of the local dose calibrator to the central dose calibrator, differences between the local activity assays were within 6%.
  
  
  CONCLUSIONS
  This study showed that quantitative accuracy and harmonized image quality can be reached in (89)Zr PET/CT multicenter studies.
authors.affiliation: Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Nikolaos E
authors.initials: NE
authors.lastname: Makris
authors.forename: Ronald
authors.initials: R
authors.lastname: Boellaard
authors.forename: Eric P
authors.initials: EP
authors.lastname: Visser
authors.forename: Johan R
authors.initials: JR
authors.lastname: de Jong
authors.forename: Bruno
authors.initials: B
authors.lastname: Vanderlinden
authors.forename: Roel
authors.initials: R
authors.lastname: Wierts
authors.forename: Berlinda J
authors.initials: BJ
authors.lastname: van der Veen
authors.forename: Henri J N M
authors.initials: HJ
authors.lastname: Greuter
authors.forename: Danielle J
authors.initials: DJ
authors.lastname: Vugts
authors.forename: Guus A M S
authors.initials: GA
authors.lastname: van Dongen
authors.forename: Adriaan A
authors.initials: AA
authors.lastname: Lammertsma
authors.forename: Marc C
authors.initials: MC
authors.lastname: Huisman
mesh_terms: D000465:Algorithms; D002138:Calibration; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D015337:Multicenter Studies as Topic; D064847:Multimodal Imaging / Q000379:methods*; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography / Q000379:methods*; D011868:Radioisotopes / Q000494:pharmacology*; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods*; D015040:Zirconium / Q000494:pharmacology*
chemical_list: D011868:Radioisotopes; D015040:Zirconium
keywords: 89Zr-PET; cross calibration; harmonization; image quality; multi-center