Advanced brain dopamine transporter imaging in mice using small-animal SPECT/CT

• Published in: EJNMMI research 2012-09, Vol.2 (1), p.55-55, Article 55
• Main Authors: Pitkonen, Miia, Hippeläinen, Eero, Raki, Mari, Andressoo, Jaan-Olle, Urtti, Arto, Männistö, Pekka T, Savolainen, Sauli, Saarma, Mart, Bergström, Kim
• Format: Article
• Language: English
• Subjects: Cardiac Imaging; Imaging; Medicin och hälsovetenskap; Medicine; Medicine & Public Health; Nuclear Medicine; Oncology; Original Research; Orthopedics; Radiology
• ISSN: 2191-219X; 2191-219X
• DOI: 10.1186/2191-219X-2-55

Background Iodine-123-β-CIT, a single-photon emission computed tomography (SPECT) ligand for dopamine transporters (DATs), has been used for in vivo studies in humans, monkeys, and rats but has not yet been used extensively in mice. To validate the imaging and analysis methods for preclinical DAT imaging, wild-type healthy mice were scanned using 123 I-β-CIT. Methods The pharmacokinetics and reliability of 123 I-β-CIT in mice ( n = 8) were studied with a multipinhole SPECT/CT camera after intravenous injection of 123 I-β-CIT (38 ± 3 MBq). Kinetic imaging of three mice was continued for 7 h postinjection to obtain the time-activity curves in the striatum and cerebellum volumes. Five mice had repeated measures 4 h post- 123 I-β-CIT injection to provide an indication of test-retest reliability. The same five mice served as a basis for a healthy mean SPECT template. Results Specific binding of 123 I-β-CIT within the mouse striatum could be clearly visualized with SPECT. The kinetics of 123 I-β-CIT was similar to that in previously published autoradiography studies. Binding potential mean values of the test-retest studies were 6.6 ± 15.7% and 6.6 ± 4.6%, respectively, and the variability was 9%. The SPECT template was aggregated from the first and second imaging of the test-retest animals. No significant difference between the templates ( P > 0.05) was found. From the test template, a striatal volume of 22.3 mm 3 was defined. Conclusions This study demonstrates that high-resolution SPECT/CT is capable of accurate, repeatable, and semiquantitative measurement of 123 I-β-CIT DAT binding in the mouse brain. This methodology will enable further studies on DAT density and neuroprotective properties of drugs in mice.