PT - JOURNAL ARTICLE AU - Jian-Qiang Lu AU - Masanori Ichise AU - Jeih-San Liow AU - Subroto Ghose AU - Doug Vines AU - Robert B. Innis TI - Biodistribution and Radiation Dosimetry of the Serotonin Transporter Ligand <sup>11</sup>C-DASB Determined from Human Whole-Body PET DP - 2004 Sep 01 TA - Journal of Nuclear Medicine PG - 1555--1559 VI - 45 IP - 9 4099 - http://jnm.snmjournals.org/content/45/9/1555.short 4100 - http://jnm.snmjournals.org/content/45/9/1555.full SO - J Nucl Med2004 Sep 01; 45 AB - 11C-Labeled 3-amino-4-(2-dimethylaminomethylphenylsulfanyl)-benzonitrile (DASB) is a selective radioligand for the in vivo quantitation of serotonin transporters (SERTs) using PET. The goal of this study was to provide dosimetry estimates for 11C-DASB based on human whole-body PET. Methods: Dynamic whole-body PET scans were acquired for 7 subjects after the injection of 669 ± 97 MBq (18.1 ± 2.6 mCi) of 11C-DASB. The acquisition for each subject was obtained at 14 time points for a total of 115 min after injection of the radioligand. Regions of interest were placed over compressed planar images of source organs that could be visually identified to generate time–activity curves. Radiation burden to the body was calculated from residence times of these source organs using the MIRDOSE3.1 program. Results: The organs with high radiation burden included the lungs, urinary bladder wall, kidneys, gallbladder wall, heart wall, spleen, and liver. The activity peaked within 10 min after the injection of 11C-DASB for all these organs except two—the excretory organs gallbladder and urinary bladder wall, which had peak activities at 32 and 22 min, respectively. Monoexponential fitting of activity overlying the urinary bladder suggested that approximately 12% of activity was excreted via the urine. Simulations in which the urinary voiding interval was decreased from 4.8 to 0.6 h produced only modest effects on the dose to the urinary bladder wall. With a 2.4-h voiding interval, the calculated effective dose was 6.98 μGy/MBq (25.8 mrem/mCi). Conclusion: The estimated radiation burden of 11C-DASB is relatively modest and would allow multiple PET examinations of the same research subject per year.