TY - JOUR T1 - VMAT2 imaging of baboons with two 18F-FP-DTBZ enantiomers JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1206 LP - 1206 VL - 50 IS - supplement 2 AU - M Ichise AU - Mark Slifstein AU - Balu Easwaramoorthy AU - SA Bae AU - A Carpenter AU - A Maffei AU - Ronald Van Heertum AU - H Kung AU - P Harris Y1 - 2009/05/01 UR - http://jnm.snmjournals.org/content/50/supplement_2/1206.abstract N2 - 1206 Objectives PET imaging of vesicular monoamine transporters 2 (VMAT2) with 11C-DTBZ is a promising biomarker of the pancreatic β cell mass. Alternatively, 18F-FP-DTBZ appears promising. One issue is how to estimate pancreatic nonspecific binding. We evaluated if renal cortex or spleen can be used as reference tissue by imaging baboons with both (+) and (-) FP-DTBZ enantiomers, (-) with little VMAT2 affinity. Methods Three male baboons underwent 2 h dynamic scans with (+) (bolus 80 MBq injection). Two of them were also scanned with (-). Additionally, 2 of them had brain scans with (+). Arterial sampling was obtained for input functions. Data were analyzed by kinetic analysis to estimate organ distribution volumes (VT) and specific distribution volumes (VS = BPP) was calculated with (-) pancreatic VT or (+) nonpancreatic organ VT as estimates of nonspecific binding. Results (+) showed excellent pancreatic uptake (10 SUV at 20 min) with a gradual washout. (-) also showed excellent pancreatic uptake (8 SUV at 6 min) but very quickly washed out . (+) in the striatum showed slightly higher uptake. Pancreatic and striatal VT with (+) were 46 ± 7 and 52 ± 7. Pancreatic VT with (-) were 13 ± 1. Renal cortex, spleen and cerebellar VT with (+) were 13 ± 1, 9 ± 2 and 12 ± 4. Using (-) pancreatic, (+) renal cortex, (+) spleen and (+) cerebellar VT as nonspecific binding, pancreatic BPP were 33 ± 9, 34 ± 9, 38 ± 7 and 31 ± 8. Striatal BPP was 40 ± 11. Conclusions 18F-FP-DTBZ allows excellent quantification of pancreatic and brain VMAT2 binding. Renal cortex may be used as the reference tissue. ER -