TY - JOUR T1 - Biodistribution and Radiation Dosimetry of <sup>18</sup>F-CP-18, a Potential Apoptosis Imaging Agent, as Determined from PET/CT Scans in Healthy Volunteers JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 2087 LP - 2092 DO - 10.2967/jnumed.113.119800 VL - 54 IS - 12 AU - Mohan Doss AU - Hartmuth C. Kolb AU - Joseph C. Walsh AU - Vani Mocharla AU - Hong Fan AU - Ashok Chaudhary AU - Zhihong Zhu AU - R. Katherine Alpaugh AU - Miriam N. Lango AU - Jian Q. Yu Y1 - 2013/12/01 UR - http://jnm.snmjournals.org/content/54/12/2087.abstract N2 - 18F-CP-18, or (18S,21S,24S,27S,30S)-27-(2-carboxyethyl)-21-(carboxymethyl)-30-((2S,3R,4R,5R,6S)-6-((2-(4-(3-F18-fluoropropyl)-1H-1,2,3-triazol-1-yl)acetamido)methyl)-3,4,5-trihydroxytetrahydro-2H-pyran-2-carboxamido)-24-isopropyl-18-methyl-17,20,23,26,29-pentaoxo-4,7,10,13-tetraoxa-16,19,22,25,28-pentaazadotriacontane-1,32-dioic acid, is being evaluated as a tissue apoptosis marker for PET imaging. The purpose of this study was to determine the biodistribution and estimate the normal-organ radiation-absorbed doses and effective dose from 18F-CP-18. Methods: Successive whole-body PET/CT scans were obtained at approximately 7, 45, 90, 130, and 170 min after intravenous injection of 18F-CP-18 in 7 healthy human volunteers. Blood samples and urine were collected between the PET/CT scans, and the biostability of 18F-CP-18 was assessed using high-performance liquid chromatography. The PET scans were analyzed to determine the radiotracer uptake in different organs. OLINDA/EXM software was used to calculate human radiation doses based on the biodistribution of the tracer. Results: 18F-CP-18 was 54% intact in human blood at 135 min after injection. The tracer cleared rapidly from the blood pool with a half-life of approximately 30 min. Relatively high 18F-CP-18 uptake was observed in the kidneys and bladder, with diffuse uptake in the liver and heart. The mean standardized uptake values (SUVs) in the bladder, kidneys, heart, and liver at around 50 min after injection were approximately 65, 6, 1.5, and 1.5, respectively. The calculated effective dose was 38 ± 4 μSv/MBq, with the urinary bladder wall having the highest absorbed dose at 536 ± 61 μGy/MBq using a 4.8-h bladder-voiding interval for the male phantom. For a 1-h voiding interval, these doses were reduced to 15 ± 2 μSv/MBq and 142 ± 15 μGy/MBq, respectively. For a typical injected activity of 555 MBq, the effective dose would be 21.1 ± 2.2 mSv for the 4.8-h interval, reduced to 8.3 ± 1.1 mSv for the 1-h interval. Conclusion: 18F-CP-18 cleared rapidly through the renal system. The urinary bladder wall received the highest radiation dose and was deemed the critical organ. Both the effective dose and the bladder dose can be reduced by frequent voiding. From the radiation dosimetry perspective, the apoptosis imaging agent 18F-CP-18 is suitable for human use. ER -