Biodistribution and radiation dosimetry of Flutemetamol (18F) injection in Japanese healthy volunteers

1510 Objectives Flutemetamol (18F) Injection is a radiopharmaceutical under development by GE Healthcare for amyloid plaque detection. The biodistribution and radiation dosimetry profiles of this radiopharmaceutical have been assessed in Japanese healthy volunteers (HVs). Methods The biodistribution of 18F following the intravenous administration of Flutemetamol (18F) Injection was measured in 6 healthy adult Japanese males using PET imaging and assays of 18F activity in whole blood, plasma and urine. Whole-body mages were acquired on a GE Discovery PET-CT scanner at up to 12 time points to 4 hours post-injection. 18F activity content was quantified at these time points in up to 15 source regions. 18F activity in red bone marrow was estimated from that measured in the lumbar vertebrae. Normalised cumulated activities (NCAs) were evaluated and organ absorbed doses calculated following the MIRD schema using the OLINDA/EXM software. The effective dose E was calculated. Results Biodistribution Initial 18F activity was primarily in liver (16.5%), brain (8.4%) and lung (7.7%). The three source regions with the highest NCAs were liver (0.520 MBq h/MBq), urinary bladder contents (0.398 MBq h/MBq) and small intestine contents (0.201 MBq h/MBq). Excretion of activity was primarily renal with 40% excreted through this pathway and 32% of the injected 18F activity excreted into the intestinal contents. Dosimetry The three organs / tissues with the highest absorbed doses were urinary bladder wall (0.114 mGy/MBq), kidneys (0.075 mGy/MBq) and liver (0.069 mGy/MBq). The E was 0.026 mSv/MBq. Conclusions There is a high brain uptake of [18F]flutemetamol, thus requiring only 185 MBq administered activity for imaging. This administered activity yields an effective dose of 4.8 mSv. The dosimetry profile of Flutemetamol (18F) Injection is comparable to most PET diagnostic radiopharmaceuticals