PT - JOURNAL ARTICLE AU - Mori, Tetsuya AU - Kiyono, Yasushi AU - Asai, Tatsuya AU - Yoshii, Yukie AU - Okazawa, Hidehiko AU - Dence, Carmen AU - Welch, Michael AU - Fujibayashi, Yasuhisa TI - Automated synthesis of 16β-[<sup>18</sup>F]fluoro-5α-dihydrotestosterone using a plastic cassette-type FDG synthesizer DP - 2010 May 01 TA - Journal of Nuclear Medicine PG - 1525--1525 VI - 51 IP - supplement 2 4099 - http://jnm.snmjournals.org/content/51/supplement_2/1525.short 4100 - http://jnm.snmjournals.org/content/51/supplement_2/1525.full SO - J Nucl Med2010 May 01; 51 AB - 1525 Objectives Androgen receptor (AR) expression is an important factor to predict tumor responsiveness to hormonal therapy in prostate cancer. 16β-[18F]fluoro-5α-dihydrotestosterone ([18F]FDHT) is a candidate for AR PET radiopharmaceutical, however, the reported method was prevented to using automatic modules because of complex reaction conditions. In this study, we developed an automatic synthesis method for [18F]FDHT using a plastic cassette-type FDG synthesizer. Methods We chose a TRACERlab MXFDG as the module for [18F]FDHT synthesis because it has the flexibility programming and accepts modification to the cassette layout in aseptic condition. Optimum labeling condition was investigated by changing several factors (amount of precursor and NaBH4, temperature and time of labeling, reduction and hydrolysis etc.) and the optimized condition is as follows: 4 mg of 16β-[[(trifluoromethyl)sulfonyl]oxy]-3,3-(ethylenedioxy)androstan-17-one in acetonitrile was heated at 125oC for 10 min with dried [18F]fluoride. The resultant solution was evaporated, and then reduced with NaBH4 in ethanol at RT. The hydrolysis with 0.1N HCl was carried out for 15 min. Results The reduction with NaBH4 was completed in 5 min. The hydrolysis was inadequacy at RT for 15 min but it was accomplished at 85oC. The radiochemical yield estimated by analytical HPLC was 52.4 ± 8.6% (n=10). The synthesis time was 55 min. Conclusions The automatic synthesis of [18F]FDHT was achieved in a cassette-type FDG synthesizer. This system would be helped routine preparation of [18F]FDHT in clinical PET center without radio-chemist