Dynamic Total-Body PET Imaging Unfolds 11 CCholine Kinetics and Dosimetry in Primary Hyperparathyroidism

This study investigated the biodistribution profile, kinetic constants, and dosimetry of 11Ccholine in patients with primary hyperparathyroidism (pHPT) using total-body dynamic PET (dPET) imaging, to establish a baseline and standard reference for clinical practice. Methods: A 50-min dPET acquisition followed by a 20-min static acquisition at 100 ± 10 min postinjection was performed on 6 patients with a clinical diagnosis of primary hyperparathyroidism. Whole-body 11Ccholine distribution and pharmacokinetics were evaluated by SUV, tissue uptake, organ-absorbed doses, and, finally, multitime graphical analysis and kinetic modeling with compartment models. Results: Rapid whole-body uptake of 11Ccholine was observed, with adequate image quality for presurgical localization of parathyroid adenomas seen from 5 min postinjection onward. Average uptake values after 50 min for liver (17.61% ± 2.82%) and bowel (5.77% ± 1.80%), compared with kidneys (2.77% ± 0.24%) and urinary bladder (0.21% ± 0.16%), suggested alternative excretion pathways for 11Ccholine other than renal clearance. Gallbladder (0.019 ± 0.004 mGy/MBq), liver (0.037 ± 0.008 mGy/MBq), pancreas (0.022 ± 0.005 mGy/MBq), kidneys (0.016 ± 0.005 mGy/MBq), and spleen (0.023 ± 0.009 mGy/MBq) were the organs with the highest observed effective doses. These organs also showcased extreme values among Formula: see text, Formula: see text, Formula: see text, and Formula: see text, which provide them with the most distinctive kinetic patterns. Parathyroid adenomas exhibited significantly higher k 3, Ki , and distribution volume, and lower K 1, than reference thyroid tissue (P Conclusion: The high adenoma-to-background uptake of 11Ccholine observed 5 min postinjection onward may facilitate swift imaging protocols. The total-body dynamic approach further highlighted the pivotal role of liver metabolism, minimal renal excretion, and unique kinetic behaviors of parathyroid adenomas. These data advance our understanding of 11Ccholine's uptake and may serve as a reference for future dPET studies.