PT  - JOURNAL ARTICLE
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
TI  - VMAT2 imaging of baboons with two 18F-FP-DTBZ enantiomers
DP  - 2009 May 01
TA  - Journal of Nuclear Medicine
PG  - 1206--1206
VI  - 50
IP  - supplement 2
4099  - http://jnm.snmjournals.org/content/50/supplement_2/1206.short
4100  - http://jnm.snmjournals.org/content/50/supplement_2/1206.full
SO  - J Nucl Med2009 May 01; 50
AB  - 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.