ISSN:
1619-7089
Keywords:
Single-photon emission tomography
;
D-2 dopamine receptor
;
Brain imaging
;
Basal ganglia
;
Eye uptake
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Preliminary study of iodine-123 labeled IBF, (S)-5-iodo-7-N-[(1-ethyl-2-pyrrolidinyl)methyl] carboxamido-2, 3-dihydrobenzofuran, has demonstrated the potential of using this agent to evaluate the status of the CNS D-2 dopamine receptor in humans. To further characterize this ligand and evaluate single-photon emission tomography (SPET) quantitation, a detailed biodistribution study in monkeys (Macaca fascicularis) with 123I- and 125I-IBF was performed. The dual tracer was simultaneously injected for in vivo imaging, biodistribution, and ex vivo autoradiography in the same monkey. After the injection, SPET data (10 min/frame × 15) were collected with a triple-head gamma camera. Dynamic imaging data indicated that IBF localized in basal ganglia (BG) with a half life of 90-120 min. Other regions, i.e., cerebellum (CB) and cortex (CX), showed very low uptake. At 2.2 h after the injection, the monkey was sacrificed. Organ distribution data indicated that, as expected, there was a significant uptake in basal ganglia (0.029% ID/g), and the BG/CB and BG/CX ratios were 17.8 and 14.2 respectively. Lower ratios were obtained from SPET image analysis (BG/CB=3.5 at 2.5h). The eye uptake was observed with SPET, but was only quantified on autoradiograms with significant uptake (0.017% ID/g). Autoradiography of the eye demonstrated that predominant uptake was localized in the ciliary body and the choroid. The selective retention and high BG/CB ratio of 123I-IBF make it a useful agent for in vivo D-2 dopamine receptor imaging with SPET.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00171012
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