Research & Industry Reports

Biodistribution and PET Imaging of [18F]- Fluoroadenosine Derivatives

Mian M. Alauddin, Antranik Shahinian, Ryan Park, Michael Tohme, John D. Fissekis, and Peter S. Conti, Department of Radiology, PET Imaging Science Center, University of Southern California, Los Angeles, CA, USA

Introduction: Many fluorinated analogues of adenosine nucleoside have been synthesized and studied as potential antitumor and antiviral agents. Earlier we reported radiosynthesis of 2´-deoxy-2´-[18F] fl uoro-1-ß-D-arabinofuranosyladenine ([18F] FAA) and 3´-deoxy-3´-[18F]fluoro-1-ß-D-xylofuranosyladenine ([18F]FXA). Now we report their in vivo studies including blood clearance, biodistribution and micro-PET imaging in tumor-bearing nude mice.

Methods: Tumors were grown in six weeks old athymic nude mice (Harlan, Indianapolis, IN) by inoculation of HT-29 cells, wild type cells in the left flank and transduced cells with HSV-tk on the right flank. When the tumor was about 1 cm in size, animals were injected with these radiotracers for in vivo studies, including blood clearance, micro-PET imaging and biodistribution.

Results: Uptake of [18F]FAA in tumor was 3.3- fold higher than blood, with highest uptake in the spleen. Maximum uptake of [18F]FXA was observed in the heart compared to other organs. There was no tumor uptake of [18F]FXA. Biodistribution results were supported by micro-PET images, which also showed very high uptake of [18F]FAA in spleen and visualization of tumors, and high uptake of [18F]FXA in the heart.

Conclusion: These results suggest that [18F]FAA may be useful for tumor imaging, while [18F]FXA may have potential as a heart imaging agent with PET.