RT Journal Article SR Electronic T1 PET-Based Human Dosimetry of 18F-Galacto-RGD, a New Radiotracer for Imaging αvβ3 Expression JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 763 OP 769 VO 47 IS 5 A1 Ambros J. Beer A1 Roland Haubner A1 Ingo Wolf A1 Michael Goebel A1 Stephan Luderschmidt A1 Markus Niemeyer A1 Anca-Ligia Grosu A1 Maria-Jose Martinez A1 Hans Jürgen Wester A1 Wolfgang A. Weber A1 Markus Schwaiger YR 2006 UL http://jnm.snmjournals.org/content/47/5/763.abstract AB 18F-Galacto-RGD is a new tracer for PET imaging of αvβ3, a receptor involved in a variety of pathologic processes including angiogenesis and metastasis. Our aim was to study the dosimetry of 18F-galacto-RGD in humans. Methods: Eighteen patients with various tumors (musculoskeletal tumors [n = 10], melanoma [n = 5], breast cancer [n = 2], or head and neck cancer [n = 1]) were examined. After injection of 133–200 MBq of 18F-galacto-RGD, 3 consecutive emission scans from the thorax to the pelvis were acquired at 6.7 ± 2.9, 35.6 ± 7.6, and 70.4 ± 12.2 min after injection. Blood samples (n = 4) for metabolite analysis were taken 10, 30, and 120 min after injection. The OLINDA 1.0 program was used to estimate the absorbed radiation dose. Results: Reversed-phase high-performance liquid chromatography of serum revealed that more than 95% of tracer was intact up to 120 min after injection. 18F-Galacto-RGD showed rapid clearance from the blood pool and primarily renal excretion. Background activity in lung and muscle tissue was low (percentage injected dose per liter at 71 min after injection, 0.56 ± 0.15 and 0.69 ± 0.25, respectively). The calculated effective dose was 18.7 ± 2.4 μSv/MBq, and the highest absorbed radiation dose was in the bladder wall (0.22 ± 0.03 mGy/MBq). Conclusion: 18F-Galacto-RGD demonstrates high metabolic stability, a favorable biodistribution, and a low radiation dose. Consequently, this tracer can safely be used for noninvasive imaging of molecular processes involving the αvβ3 integrin and for the planning and monitoring of therapeutic approaches targeting αvβ3.