PT  - JOURNAL ARTICLE
AU  - Steven M. Larson
AU  - Michael Morris
AU  - Ilonka Gunther
AU  - Brad Beattie
AU  - John L. Humm
AU  - Timothy A. Akhurst
AU  - Ronald D. Finn
AU  - Yusuf Erdi
AU  - Keith Pentlow
AU  - Jon Dyke
AU  - Olivia Squire
AU  - William Bornmann
AU  - Timothy McCarthy
AU  - Michael Welch
AU  - Howard Scher
TI  - Tumor Localization of 16β-<sup>18</sup>F-Fluoro-5α-Dihydrotestosterone Versus <sup>18</sup>F-FDG in Patients with Progressive, Metastatic Prostate Cancer
DP  - 2004 Mar 01
TA  - Journal of Nuclear Medicine
PG  - 366--373
VI  - 45
IP  - 3
4099  - http://jnm.snmjournals.org/content/45/3/366.short
4100  - http://jnm.snmjournals.org/content/45/3/366.full
SO  - J Nucl Med2004 Mar 01; 45
AB  - 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.