Whole-body biodistribution and radiation dosimetry of 18F-FP-(+)-DTBZ (18F-AV-133): a novel vesicular monoamine transporter 2 imaging agent.
Vesicular monoamine transporter 2 (VMAT2) is highly expressed in the endocrine cells and brain. We investigated the biodistribution and radiation dosimetry of (2R,3R,11bR)-9-(3-(18)F-fluoropropoxy)-3-isobutyl-10-methoxy-2,3,4,6,7,11b-hexahydro-1H-pyrido[2,1-a]isoquinolin-2-ol ((18)F-FP-(+)-dihydrotetrabenazine [DTBZ] or (18)F-AV-133), a potential VMAT2 imaging agent showing encouraging results in humans, to facilitate its future clinical use.


METHODS
Nine healthy human subjects (mean age +/- SD, 58.6 +/- 4.2 y) were enrolled for the whole-body PET scan. Serial images were acquired for 3 h immediately after a bolus injection of 390.7 +/- 22.9 MBq of (18)F-AV-133 per individual. The source organs were delineated on PET/CT images. The OLINDA/EXM application was used to determine the equivalent dose for individual organs.


RESULTS
The radiotracer did not show any noticeable adverse effects for the 9 subjects examined. The radioactivity uptake in the brain was the highest at 7.5% +/- 0.6% injected dose at 10 min after injection. High absorbed doses were found in the pancreas, liver, and upper large intestine wall. The highest-dosed organ, which received 153.3 +/- 23.8 microGy/MBq, was the pancreas. The effective dose equivalent and effective dose for (18)F-AV-133 were 36.5 +/- 2.8 and 27.8 +/- 2.5 microSv/MBq, respectively. These values are comparable to those reported for any other (18)F-labeled radiopharmaceutical.


CONCLUSIONS
(18)F-AV-133 is safe, with appropriate biodistribution and radiation dosimetry for imaging VMAT2 sites in humans.
Lin
Kun-Ju
KJ
Department of Nuclear Medicine and Molecular Imaging Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
Weng
Yi-Hsin
YH
Wey
Shiaw-Pyng
SP
Hsiao
Ing-Tsung
IT
Lu
Chin-Song
CS
Skovronsky
Daniel
D
Chang
Hsiu-Ping
HP
Kung
Mei-Ping
MP
Yen
Tzu-Chen
TC
D064420:Drug-Related Side Effects and Adverse Reactions; D005260:Female; D005462:Fluorine Radioisotopes; D006801:Humans; D008297:Male; D008875:Middle Aged; D057054:Molecular Imaging / Q000379:methods*; D010300:Parkinson Disease / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography; D011874:Radiometry; D013747:Tetrabenazine / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D050493:Vesicular Monoamine Transport Proteins / Q000378:metabolism*
D005462:Fluorine Radioisotopes; D050493:Vesicular Monoamine Transport Proteins; C549477:florbenazine F 18; D013747:Tetrabenazine