A Short Dynamic Scan Method of Measuring Bone Metabolic Flux Using [<sup>18</sup>F]NaF PET
Tanuj Puri,
Musib M. Siddique,
Michelle L. Frost,
Amelia E. B. Moore,
Glen M. Blake
Affiliations
Tanuj Puri
Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King’s College London, 4th Floor Lambeth Wing, St. Thomas’ Hospital, London SE1 7EH, UK
Musib M. Siddique
Radcliffe Department of Medicine, Level 6 West Wing, John Radcliffe Hospital, Headley Way, Headington, Oxford OX3 9DU, UK
Michelle L. Frost
Institute of Cancer Research Clinical Trials & Statistics Unit (ICR-CTSU), Institute of Cancer Research, 15 Cotswold Road, Sutton SM2 5NG, UK
Amelia E. B. Moore
Department of Cancer Imaging, School of Biomedical Engineering and Imaging Sciences, King’s College London, 4th Floor Lambeth Wing, St. Thomas’ Hospital, London SE1 7EH, UK
Glen M. Blake
Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King’s College London, 4th Floor Lambeth Wing, St. Thomas’ Hospital, London SE1 7EH, UK
[18F]NaF PET measurements of bone metabolic flux (Ki) are conventionally obtained with 60-min dynamic scans analysed using the Hawkins model. However, long scan times make this method expensive and uncomfortable for subjects. Therefore, we evaluated and compared measurements of Ki with shorter scan times analysed with fixed values of the Hawkins model rate constants. The scans were acquired in a trial in 30 postmenopausal women, half treated with teriparatide (TPT) and half untreated. Sixty-minute PET-CT scans of both hips were acquired at baseline and week 12 after injection with 180 MBq [18F]NaF. Scans were analysed using the Hawkins model by fitting bone time–activity curves at seven volumes of interest (VOIs) with a semi-population arterial input function. The model was re-run with fixed rate-constants for dynamic scan times from 0–12 min increasing in 4-min steps up to 0–60 min. Using the Hawkins model with fixed rate-constants, Ki measurements with statistical power equivalent or superior to conventionally analysed 60-min dynamic scans were obtained with scan times as short as 12 min.