title: Harmonizing FDG PET quantification while maintaining optimal lesion detection: prospective multicentre validation in 517 oncology patients.
abstract: OBJECTIVE
  Point-spread function (PSF) or PSF + time-of-flight (TOF) reconstruction may improve lesion detection in oncologic PET, but can alter quantitation resulting in variable standardized uptake values (SUVs) between different PET systems. This study aims to validate a proprietary software tool (EQ.PET) to harmonize SUVs across different PET systems independent of the reconstruction algorithm used.
  
  
  METHODS
  NEMA NU2 phantom data were used to calculate the appropriate filter for each PSF or PSF+TOF reconstruction from three different PET systems, in order to obtain EANM compliant recovery coefficients. PET data from 517 oncology patients were reconstructed with a PSF or PSF+TOF reconstruction for optimal tumour detection and an ordered subset expectation maximization (OSEM3D) reconstruction known to fulfil EANM guidelines. Post-reconstruction, the proprietary filter was applied to the PSF or PSF+TOF data (PSFEQ or PSF+TOFEQ). SUVs for PSF or PSF+TOF and PSFEQ or PSF+TOFEQ were compared to SUVs for the OSEM3D reconstruction. The impact of potential confounders on the EQ.PET methodology including lesion and patient characteristics was studied, as was the adherence to imaging guidelines.
  
  
  RESULTS
  For the 1380 tumour lesions studied, Bland-Altman analysis showed a mean ratio between PSF or PSF+TOF and OSEM3D of 1.46 (95%CI: 0.86-2.06) and 1.23 (95%CI: 0.95-1.51) for SUVmax and SUVpeak, respectively. Application of the proprietary filter improved these ratios to 1.02 (95%CI: 0.88-1.16) and 1.04 (95%CI: 0.92-1.17) for SUVmax and SUVpeak, respectively. The influence of the different confounding factors studied (lesion size, location, radial offset and patient's BMI) was less than 5%. Adherence to the European Association of Nuclear Medicine (EANM) guidelines for tumour imaging was good.
  
  
  CONCLUSIONS
  These data indicate that it is not necessary to sacrifice the superior lesion detection and image quality achieved by newer reconstruction techniques in the quest for harmonizing quantitative comparability between PET systems.
authors.affiliation: Nuclear Medicine Department, François Baclesse Cancer Centre, Caen, France.
authors.forename: Elske
authors.initials: E
authors.lastname: Quak
authors.affiliation: Nuclear Medicine Department, University Hospital and EA3878 (GETBO) IFR 148, Brest, France.
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Le Roux
authors.affiliation: Centre for Molecular Imaging, Peter MacCallum Cancer Centre, East Melbourne and University of Melbourne, Melbourne, Australia.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Hofman
authors.affiliation: Nuclear Medicine Department, University Hospital and EA3878 (GETBO) IFR 148, Brest, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Robin
authors.affiliation: Nuclear Medicine Department, University Hospital and EA3878 (GETBO) IFR 148, Brest, France.
authors.forename: David
authors.initials: D
authors.lastname: Bourhis
authors.affiliation: Centre for Molecular Imaging, Peter MacCallum Cancer Centre, East Melbourne and University of Melbourne, Melbourne, Australia.
authors.forename: Jason
authors.initials: J
authors.lastname: Callahan
authors.affiliation: Centre for Molecular Imaging, Peter MacCallum Cancer Centre, East Melbourne and University of Melbourne, Melbourne, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Binns
authors.affiliation: Nuclear Medicine Department, University Hospital, Avenue Côte de Nacre, 14000, Caen, France.
authors.forename: Cédric
authors.initials: C
authors.lastname: Desmonts
authors.affiliation: Nuclear Medicine Department, University Hospital and EA3878 (GETBO) IFR 148, Brest, France.
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Salaun
authors.affiliation: Centre for Molecular Imaging, Peter MacCallum Cancer Centre, East Melbourne and University of Melbourne, Melbourne, Australia.
authors.forename: Rodney J
authors.initials: RJ
authors.lastname: Hicks
authors.affiliation: Nuclear Medicine Department, François Baclesse Cancer Centre, Caen, France. aide-n@chu-caen.fr.|Nuclear Medicine Department, University Hospital, Avenue Côte de Nacre, 14000, Caen, France. aide-n@chu-caen.fr.|INSERM 1199, François Baclesse Cancer Centre, Caen, France. aide-n@chu-caen.fr.|Normandie University, Caen, France. aide-n@chu-caen.fr.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Aide
mesh_terms: D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008113:Liver Neoplasms / Q000000981:diagnostic imaging*; D008228:Lymphoma, Non-Hodgkin / Q000000981:diagnostic imaging*; D008297:Male; D008545:Melanoma / Q000000981:diagnostic imaging*; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods* / Q000592:standards; D019275:Radiopharmaceuticals
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: FDG PET/CT; Harmonization; Quantification; Standardized uptake value; Tumour imaging