RT Journal Article SR Electronic T1 18F-ICMT-11, a Caspase-3–Specific PET Tracer for Apoptosis: Biodistribution and Radiation Dosimetry JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1551 OP 1556 DO 10.2967/jnumed.112.118760 VO 54 IS 9 A1 Amarnath Challapalli A1 Laura M. Kenny A1 William A. Hallett A1 Kasia Kozlowski A1 Giampaolo Tomasi A1 Mihir Gudi A1 Adil Al-Nahhas A1 R. Charles Coombes A1 Eric O. Aboagye YR 2013 UL http://jnm.snmjournals.org/content/54/9/1551.abstract AB Effective anticancer therapy induces tumor cell death through apoptosis. Noninvasive monitoring of apoptosis during therapy may provide predictive outcome information and help tailor treatment. A caspase-3–specific imaging radiotracer, 18F-(S)-1-((1-(2-fluoroethyl)-1H-[1,2,3]-triazol-4-yl)methyl)-5-(2(2,4-difluorophenoxymethyl)-pyrrolidine-1-sulfonyl)isatin (18F-ICMT-11), has been developed for use in PET studies. We report the safety, biodistribution, and internal radiation dosimetry profiles of 18F-ICMT-11 in 8 healthy human volunteers. Methods: 18F-ICMT-11 was intravenously administered as a bolus injection (mean ± SD, 159 ± 2.75 MBq; range, 154–161 MBq) to 8 healthy volunteers (4 men, 4 women). Whole-body (vertex to mid thigh) PET/CT scans were acquired at 6 time points, up to 4 h after tracer injection. Serial whole blood, plasma, and urine samples were collected for radioactivity measurement and radiotracer stability. In vivo 18F activities were determined from quantitative analysis of the images, and time–activity curves were generated. The total numbers of disintegrations in each organ normalized to injected activity (residence times) were calculated as the area under the curve of the time–activity curve, normalized to injected activities and standard values of organ volumes. Dosimetry calculations were then performed using OLINDA/EXM 1.1. Results: Injection of 18F-ICMT-11 was well tolerated in all subjects, with no serious tracer-related adverse events reported. The mean effective dose averaged over both men and women was estimated to be 0.025 ± 0.004 mSv/MBq (men, 0.022 ± 0.004 mSv/MBq; women, 0.027 ± 0.004 mSv/MBq). The 5 organs receiving the highest absorbed dose (mGy/MBq), averaged over both men and women, were the gallbladder wall (0.59 ± 0.44), small intestine (0.12 ± 0.05), upper large intestinal wall (0.08 ± 0.07), urinary bladder wall (0.08 ± 0.02), and liver (0.07 ± 0.01). Elimination was both renal and via the hepatobiliary system. Conclusion: 18F-ICMT-11 is a safe PET tracer with a dosimetry profile comparable to other common 18F PET tracers. These data support the further development of 18F-ICMT-11 for clinical imaging of apoptosis.