[18F]BAY 85-8050 (TIM-1): A novel tumor specific probe for PET/CT imaging - Dosimetry

1434 Objectives The glutamatic acid derivative TIM-1 (4-[18F]Fluoro glutamic acid), a new PET tracer for the detection of malignant diseases, displayed promising results in patients with NSCLC, breast cancer and malignant melanoma. The aim of this study was to provide dosimetry estimates for TIM-1 based on human whole-body PET/CT measurements. Methods PET/CT scans were performed in 5 healthy volunteers (mean age: 53 years; range 51 to 55: 3 male, 2 female). Human subjects were imaged for up to 270 min using a Siemens Biograph 64 TruePoint PET/CT scanner (7 bed positions/frame, 1 min /bed position, iterative re-construction) after i.v. injection of 305±17.6 MBq TIM-1. Whole body and organ-specific VOIs were created for each subject (whole body, brain, heart, blood pool, pancreas, kidneys, bone, urinary bladder) using PMOD v.3.1. Time Activity Curves (TACs) were determined for the whole body and all regions. TACS were fitted to exponential equations to determine the effective doses (EDs). Estimates of the absorbed dose were calculated using the FDA approved OLINDA software. Results Preliminary results show that uptake was highest in the kidneys due to the renal excretion of the tracer, followed by pancreas, osteogenic cells and heart wall. The individual values of the organ doses were: kidneys (25,3±4,4 μSv/MBq), pancreas (18,7±1,8 μSv/MBq), osteogenic cells (12,1±2,2 μSv/MBq) and heart wall (11,6±1,3 μSv/MBq). The calculated effective dose was 8,8±0,9 μSv/MBq. Conclusions Based on the distribution and dose estimates, the estimated radiation dose for TIM-1 is favourable with 2,64±0,2 mSv at a patient dose of 300 MBq, and therefore lower than that of [18F]FDG. Research Support The trial is sponsored and supported by Bayer Schering Pharma