Human [123I]5-I-A-85380 dynamic SPECT studies in normals: Kinetic analysis and parametric imaging

Yun Zhou, James R. Brasic, John L. Musachio, Stephen R. Zukin, Hiroto Kuwabara, Andrew H. Crabb, Christopher J. Endres, John Hilton, Hong Fan, Dean F. Wong

Research output: Contribution to conferencePaperpeer-review

10 Scopus citations


[123I]5-I-A-85380 ([123I]5-IA) is a ligand specific for the α4β2 nicotinic acetylcholine receptor (nAChR) subtype. It was reported that distribution volume (DV) is an appropriate measurement for α4β2 nAChR density in baboon [123I]5-IA dynamic SPECT studies. To evaluate the kinetics obtained from human [123I]5-IA dynamic SPECT, three different methods were applied to region of interest (ROI) kinetics analysis as folows: A: a 2-compartment 3-parameters model, B: 3-compartment 5-parameter model, and C: same model as in B but fitting with a constraint of ratio of K1/k2e estimated by fitting occipital kinetics to model in A. The DV was estimated as DV = K1/k2 for A, and DV=(K1/k2)(1+k3/k4) for B and C. Nonlinear least squares fitting using Marquardt algorithm was performed for A-C. Akaike information criterion (AIC) and R2 were used for evaluation of fitting results. A linear parametric imaging algorithm derived from model in method A was used for generating images of K1 and DV. Four normal human [123I]5-IA dynamic studies were evaluated by A-C. In each study, after a bolus of [123I]5-IA (5∼10 mCi, specific activity>10 Ci/umol) was injected intravenously, a dynamic scanning with 20 acquisitions over 6 hour was started immediately on a Trionix TriadXLT scanner. 30-40 arterial plasma samples were taken during the study and HPLC was performed to determine the metabolite-corrected arterial plasma radioactivity as input function. The ROI regions (cerebellum, frontal cortex, occipital cortex, pones, and thalamus) were drawn on co-registered MRI images. Results show that A fits to all ROI kinetics very well (R2>0.99), and paired T-test for AIC showed there is no statistical significantly improvement of model fitting from B, C methods The K1 and DV images are of good image quality. Conclusion: A is best for ROI kinetic analysis and parametric imaging for DV and K1.

Original languageEnglish
Number of pages6
StatePublished - 2001
Event2001 IEEE Nuclear Science Symposium Conference Record - San Diego, CA, United States
Duration: Nov 4 2001Nov 10 2001


Conference2001 IEEE Nuclear Science Symposium Conference Record
Country/TerritoryUnited States
CitySan Diego, CA


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