DOI: 10.1007/s00259-018-3977-4Pages: 1344-1361

Feasibility of state of the art PET/CT systems performance harmonisation

1. North Estonia Medical Centre Foundation, Department of Medical Technology

2. University of Szeged, Department of Nuclear Medicine

3. On behalf of EANM Research Limited (EARL)

4. Catharina Hospital, Department of Medical Physics

5. VU University Medical Center, Department of Radiology and Nuclear Medicine

6. Martini Hospital, Department of Radiology

7. Johns Hopkins University, Russell H. Morgan Department of Radiology and Radiological Science

8. University of Groningen, University Medical Centre Groningen, Department of Nuclear Medicine and Molecular Imaging

Correspondence to:
Ronald Boellaard
Tel: +31-(0)50-3613471




The objective of this study was to explore the feasibility of harmonising performance for PET/CT systems equipped with time-of-flight (ToF) and resolution modelling/point spread function (PSF) technologies. A second aim was producing a working prototype of new harmonising criteria with higher contrast recoveries than current EARL standards using various SUV metrics.


Four PET/CT systems with both ToF and PSF capabilities from three major vendors were used to acquire and reconstruct images of the NEMA NU2–2007 body phantom filled conforming EANM EARL guidelines. A total of 15 reconstruction parameter sets of varying pixel size, post filtering and reconstruction type, with three different acquisition durations were used to compare the quantitative performance of the systems. A target range for recovery curves was established such that it would accommodate the highest matching recoveries from all investigated systems. These updated criteria were validated on 18 additional scanners from 16 sites in order to demonstrate the scanners’ ability to meet the new target range.


Each of the four systems was found to be capable of producing harmonising reconstructions with similar recovery curves. The five reconstruction parameter sets producing harmonising results significantly increased SUVmean (25%) and SUVmax (26%) contrast recoveries compared with current EARL specifications. Additional prospective validation performed on 18 scanners from 16 EARL accredited sites demonstrated the feasibility of updated harmonising specifications. SUVpeak was found to significantly reduce the variability in quantitative results while producing lower recoveries in smaller (≤17 mm diameter) sphere sizes.


Harmonising PET/CT systems with ToF and PSF technologies from different vendors was found to be feasible. The harmonisation of such systems would require an update to the current multicentre accreditation program EARL in order to accommodate higher recoveries. SUVpeak should be further investigated as a noise resistant alternative quantitative metric to SUVmax.

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  • Accepted: Feb 12, 2018
  • Online: Mar 2, 2018

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