@article {Larson366, author = {Steven M. Larson and Michael Morris and Ilonka Gunther and Brad Beattie and John L. Humm and Timothy A. Akhurst and Ronald D. Finn and Yusuf Erdi and Keith Pentlow and Jon Dyke and Olivia Squire and William Bornmann and Timothy McCarthy and Michael Welch and Howard Scher}, title = {Tumor Localization of 16β-18F-Fluoro-5α-Dihydrotestosterone Versus 18F-FDG in Patients with Progressive, Metastatic Prostate Cancer }, volume = {45}, number = {3}, pages = {366--373}, year = {2004}, publisher = {Society of Nuclear Medicine}, abstract = {This trial was an initial assessment of the feasibility, in vivo targeting, and biokinetics of 16β-18F-fluoro-5α-dihydrotestosterone (18F-FDHT) PET in patients with metastatic prostate cancer to assess androgen receptor expression. Methods: Seven patients with progressive clinically metastatic prostate cancer underwent 18F-FDG and 18F-FDHT PET scans in addition to conventional imaging methods. Three patients had their studies repeated 1 mo later, 2 while on testosterone therapy, and the third after treatment with 17-allylamino-17-demethoxygeldanamycin (17-AAG). High-pressure liquid radiochromatography was used to separate 18F-FDHT from radiolabeled metabolites. Lesion-by-lesion comparisons between the 18F-FDHT, 18F-FDG, and conventional imaging methods were performed. Results: Metabolism of 18F-FDHT was rapid, with 80\% conversion within 10 min to radiolabeled metabolites that circulated bound to plasma proteins. Tumor uptake was rapid and tumor retention was prolonged. Fifty-nine lesions were identified by conventional imaging methods. 18F-FDG PET was positive in 57 of 59 lesions (97\%), with an average lesion maximum standardized uptake value (SUVmax) = 5.22. 18F-FDHT PET was positive in 46 of 59 lesions (78\%), with the average positive lesion SUVmax = 5.28. Treatment with testosterone resulted in diminished 18F-FDHT uptake at the tumor site. Conclusion: 18F-FDHT localizes to tumor sites in patients with progressive clinically metastatic prostate cancer and may be a promising agent to analyze antigen receptors and their impact on the clinical management of prostate cancer.}, issn = {0161-5505}, URL = {https://jnm.snmjournals.org/content/45/3/366}, eprint = {https://jnm.snmjournals.org/content/45/3/366.full.pdf}, journal = {Journal of Nuclear Medicine} }