Evaluation of Pancreatic VMAT2 Binding with Active and Inactive Enantiomers of [18 F]FP-DTBZ in Healthy Subjects and Patients with Type 1 Diabetes
Abstract
Previous studies demonstrated the utility of [18F]fluoropropyl-(+)-dihydrotetrabenazine ([18F]FP-(+)-DTBZ) as a positron emission tomography (PET) radiotracer for the vesicular monoamine transporter type 2 (VMAT2) to quantify beta cell mass in healthy control (HC) and type 1 diabetes mellitus (T1DM) groups. Quantification of specific binding requires measurement of non-displaceable uptake. Our goal was to identify a reference tissue (renal cortex or spleen) to quantify pancreatic non-specific binding of [18F]FP-(+)-DTBZ with the inactive enantiomer, [18F]FP-(-)-DTBZ. This was the first human study of [18F]FP-(-)-DTBZ. Six HCs and four T1DM patients were scanned on separate days after injection of [18F]FP-(+)-DTBZ or [18F]FP-(-)-DTBZ. Distribution volumes (VT) and standardized uptake values (SUVs) were compared between groups. Three methods for calculation of non-displaceable uptake (VND) or reference SUV were applied: (1) use of [18F]FP-(+)-DTBZ reference VT as VND, assuming VND is uniform across organs; (2) use of [18F]FP-(-)-DTBZ pancreatic VT as VND, assuming that VND is uniform between enantiomers in the pancreas; and (3) use of a scaled [18F]FP-(+)-DTBZ reference VT as VND, assuming that a ratio of non-displaceable uptake ...Continue Reading
References
Citations
An Efficient Automated Radiosynthesis and Bioactivity Confirmation of VMAT2 Tracer [18F]FP-(+)-DTBZ.
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