Dale L Bailey1,2, Michael S Hofman3, Nicholas J Forwood4,2, Graeme J O'Keefe5, Andrew M Scott5,6, Winifred M van Wyngaardt7, Bonnie Howe7, Olga Kovacev8, Roslyn J Francis8,9. 1. Department of Nuclear Medicine, Royal North Shore Hospital, Sydney, Australia dale.bailey@sydney.edu.au. 2. Faculty of Health Sciences, University of Sydney, Sydney, Australia. 3. Molecular Imaging, Department of Cancer Imaging, Peter MacCallum Cancer Institute, Melbourne, Australia. 4. Department of Nuclear Medicine, Royal North Shore Hospital, Sydney, Australia. 5. Department of Molecular Imaging and Therapy, Austin Health, and University of Melbourne, Melbourne, Australia. 6. Olivia Newton-John Cancer Research Institute and La Trobe University, Melbourne, Australia. 7. Radionuclide Metrology Group, Nuclear Stewardship, ANSTO, Sydney, Australia. 8. Australasian Radiopharmaceutical Trials Network (ARTnet), Australia; and. 9. Department of Nuclear Medicine, Sir Charles Gairdner Hospital, Perth, Australia.
Abstract
We report the discovery of a systematic miscalibration during the work-up process for site validation of a multicenter clinical PET imaging trial using 68Ga, which manifested as a consistent and reproducible underestimation in the quantitative accuracy (assessed by SUV) of a range of PET systems from different manufacturers at several different facilities around Australia. Methods: Sites were asked to follow a strict preparation protocol to create a radioactive phantom with 68Ga to be imaged using a standard clinical protocol before commencing imaging in the trial. All sites had routinely used 68Ga for clinical PET imaging for many years. The reconstructed image data were transferred to an imaging core laboratory for analysis, along with information about ancillary equipment such as the radionuclide dose calibrator. Fourteen PET systems were assessed from 10 nuclear medicine facilities in Australia, with the aim for each PET system being to produce images within 5% of the true SUV. Results: At initial testing, 10 of the 14 PET systems underestimated the SUV by 15% on average (range, 13%-23%). Multiple PET systems at one site, from two different manufacturers, were all similarly affected, suggesting a common cause. We eventually identified an incorrect factory-shipped dose calibrator setting from a single manufacturer as being the cause. The calibrator setting for 68Ga was subsequently adjusted by the users so that the reconstructed images produced accurate values. Conclusion: PET imaging involves a chain of measurements and calibrations to produce accurate quantitative performance. Testing of the entire chain is simple, however, and should form part of any quality assurance program or prequalifying site assessment before commencing a quantitative imaging trial or clinical imaging.
We report the discovery of a systematic miscalibration during the work-up process for site validation of a multicenter clinical PET imaging trial using 68Ga, which manifested as a consistent and reproducible underestimation in the quantitative accuracy (assessed by SUV) of a range of PET systems from different manufacturers at several different facilities around Australia. Methods: Sites were asked to follow a strict preparation protocol to create a radioactive phantom with 68Ga to be imaged using a standard clinical protocol before commencing imaging in the trial. All sites had routinely used 68Ga for clinical PET imaging for many years. The reconstructed image data were transferred to an imaging core laboratory for analysis, along with information about ancillary equipment such as the radionuclide dose calibrator. Fourteen PET systems were assessed from 10 nuclear medicine facilities in Australia, with the aim for each PET system being to produce images within 5% of the true SUV. Results: At initial testing, 10 of the 14 PET systems underestimated the SUV by 15% on average (range, 13%-23%). Multiple PET systems at one site, from two different manufacturers, were all similarly affected, suggesting a common cause. We eventually identified an incorrect factory-shipped dose calibrator setting from a single manufacturer as being the cause. The calibrator setting for 68Ga was subsequently adjusted by the users so that the reconstructed images produced accurate values. Conclusion: PET imaging involves a chain of measurements and calibrations to produce accurate quantitative performance. Testing of the entire chain is simple, however, and should form part of any quality assurance program or prequalifying site assessment before commencing a quantitative imaging trial or clinical imaging.
Authors: Mathieu Gaudreault; David Chang; Nicholas Hardcastle; Price Jackson; Tomas Kron; Michael S Hofman; Shankar Siva Journal: Clin Transl Radiat Oncol Date: 2022-05-17
Authors: Daphne M V Huizing; Daniëlle Koopman; Jorn A van Dalen; Martin Gotthardt; Ronald Boellaard; Terez Sera; Michiel Sinaasappel; Marcel P M Stokkel; Berlinda J de Wit-van der Veen Journal: EJNMMI Phys Date: 2019-11-08
Authors: Mathieu Gaudreault; David Chang; Nicholas Hardcastle; Price Jackson; Tomas Kron; Gerard G Hanna; Michael S Hofman; Shankar Siva Journal: Front Oncol Date: 2022-04-12 Impact factor: 5.738