RT Journal Article SR Electronic T1 Biodistribution and Radiation Dosimetry Estimates of 1-(2′-Deoxy-2′-18F-Fluoro-1-β-d-Arabinofuranosyl)-5-Bromouracil: PET Imaging Studies in Dogs JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1916 OP 1922 VO 46 IS 11 A1 Sridhar Nimmagadda A1 Thomas J. Mangner A1 Haihao Sun A1 Raymond W. Klecker, Jr. A1 Otto Muzik A1 Jawana M. Lawhorn-Crews A1 Kirk A. Douglas A1 Jerry M. Collins A1 Anthony F. Shields YR 2005 UL http://jnm.snmjournals.org/content/46/11/1916.abstract AB This study reports on the biodistribution and radiation estimates of 1-(2′-deoxy-2′-18F-fluoro-1-β-d-arabinofuranosyl)-5-bromouracil (18F-FBAU), a potential tracer for imaging DNA synthesis. Methods: Three normal dogs were intravenously administered 18F-FBAU and a dynamic PET scan was performed for 60 min over the upper abdomen followed by a whole-body scan for a total of 150 min. Blood samples were collected at stipulated time intervals to evaluate tracer clearance and metabolism. Tissue samples of various organs were analyzed for tracer uptake and DNA incorporation. Dynamic accumulation of the tracer in different organs was derived from reconstructed PET images. The radiation dosimetry of 18F-FBAU was evaluated using the MIRD method. Results: At 60 min after injection, blood analysis found >90% of the activity in unmetabolized form. At 2 h after injection, 18F-FBAU uptake was highest in proliferating tissues (mean SUVs: marrow, 2.6; small intestine, 4.0), whereas nonproliferative tissues showed little uptake (mean SUVs: muscle, 0.75; lung, 0.70; heart, 0.85; liver, 1.28). Dynamic image analysis over 60 min showed progressive uptake of the tracer in marrow. Extraction studies demonstrated that most of the activity in proliferative tissues was in the acid-insoluble fraction (marrow, 83%; small intestine, 73%), consistent with incorporation into DNA. In nonproliferative tissue, most of the activity was not found in the acid-insoluble fraction (>84% for heart, muscle, and liver). Conclusion: These results demonstrate that 18F-FBAU was resistant to metabolism, readily incorporated into DNA in proliferating tissues, and showed good contrast between organs of variable DNA synthesis. These findings indicate that 18F-FBAU may find use in measuring DNA synthesis with PET.