Validation of the Octamouse for Simultaneous 18F-Fallypride Small-Animal PET Recordings from 8 Mice

Journal of Nuclear Medicine

Shanshan Zhang¹  Björn Wängler¹  Paul Cumming¹  Franz Josef Gildehaus¹  Peter Bartenstein¹  Stefan Förster¹  Axel Rominger¹  Erik Mille¹  Guido Böning¹  Sebastian Nowak¹ 

关键词: Octamouse holder;    dopamine D_2/3 receptor;    fallypride;    small-animal PET;    mouse brain;   

DOI  :  10.2967/jnumed.110.078451

学科分类：医学（综合）

来源: Society of Nuclear Medicine

【 摘 要 】

Data collection in preclinical small-animal PET studies has been hindered by the small number of recordings typically obtained for a single radiosynthesis. Therefore, we tested procedures for obtaining 8 simultaneous small-animal PET recordings from the brains of 8 mice using an acrylic anesthesia distributor (the Octamouse), with the dopamine D2/3 ligand 18F-fallypride serving as a test substance for brain receptor imaging. Methods: The effect of scatter correction on the small-animal PET recordings was first evaluated in phantom studies in which sources of different radioactivity concentration were placed within the chambers of the Octamouse. Next, potential effects of mass on the 18F-fallypride binding potential (BPND) in the striatum were tested in groups of mice receiving 18F-fallypride at 2 different specific activities (140 and 50 GBq/μmol), with and without scatter correction. Finally, the relationship between BPND and injected dose of 18F-fallypride (3.5–17 MBq/mouse) was tested. Results: Scatter correction improved the contrast between sources and air space within the Octamouse phantom. The magnitude of 18F-fallypride BPND in mouse striatum was invariant across the tested range of specific activities, and scatter correction increased BPND by a mean of 6%; covariances of the inter- and intraoperator variability of BPND were 10%. There was a positive correlation between radiochemical dose and BPND with (R2 = 0.53) and without (R2 = 0.63) scatter correction, which was driven by increasing area under the percentage injected dose curve in the striatum. Conclusion: The quantitation of emission sources placed within the Octamouse is linear over a wide range of source activities. In the striatum of living mice, the magnitude of 18F-fallypride BPND was highly reproducible between operators and was constant over a 3-fold range of specific activities, indicating a lack of significant occupancy. Scatter correction improved quantitation but did not entirely correct for the dependence of BPND on injected dose, which was deemed to arise because of effects propagating from detector dead time when the total radiochemical dose in the field of view exceeded 50 MBq. Given this consideration, we were still able to quantify 18F-fallypride BPND in 16 mice from a single radiosynthesis, an economy that should be generalizable to brain studies of diverse radioligands.

【 授权许可】

Unknown