Dual-radiotracer translational SPECT neuroimaging. Comparison of three methods for the simultaneous brain imaging of D 2/3 and 5-HT 2A receptors

Article Article scientifique Article Dual-radiotracer translational SPECT neuroimaging. Comparison of three methods for the simultaneous brain imaging of D 2/3 and 5-HT 2A receptors eng 2018 author Tsartsalis Stergios 0000-0002-6565-6313 782369 author Tournier Benjamin 705309 author Habiby Alaoui Sélim 823723 author Ben Hamadi Meriem 690823 author Barca Cristina 692170 author Ginovart Nathalie 0000-0003-1684-6599 637504 author Millet Philippe 0000-0002-5803-0478 668343 528-540 10.1016/j.neuroimage.2018.04.063 29723640 1053-8119 http://linkinghub.elsevier.com/retrieve/pii/S1053811918303835 PURPOSE: SPECT imaging with two radiotracers at the same time is feasible if two different radioisotopes are employed, given their distinct energy emission spectra. In the case of (123)I and (125)I, dual SPECT imaging is not straightforward: (123)I emits photons at a principal energy emission spectrum of 143.1-179.9keV. However, it also emits at a secondary energy spectrum (15-45keV) that overlaps with the one of (125)I and the resulting cross-talk of emissions impedes the accurate quantification of (125)I. In this paper, we describe three different methods for the correction of this cross-talk and the simultaneous in vivo [(123)I]IBZM and [(125)I]R91150 imaging of D2/3 and 5-HT2A receptors in the rat brain. METHODS: Three methods were evaluated for the correction of the effect of cross-talk in a series of simultaneous, [(123)I]IBZM and [(125)I]R91150 in vivo and phantom SPECT scans. Method 1 employs a dual-energy window (DEW) approach, in which the cross-talk on (125)I is considered a stable fraction of the energy emitted from (123)I at the principal emission spectrum. The coefficient describing the relationship between the emission of (123)I at the principal and the secondary spectrum was estimated from a series of single-radiotracer [(123)I]IBZM SPECT studies. In Method 2, spectral factor analysis (FA) is applied to separate the radioactivity from (123)I and (125)I on the basis of their distinct emission patterns across the energy spectrum. Method 3 uses a modified simplified reference tissue model (SRTMC) to describe the kinetics of [(125)I]R91150. [...] RESULTS: Average regional BPND values of [(125)I]R91150, estimated on the cross-talk corrected dual-radiotracer SPECT studies provided satisfactory correlations with the BPND values for [(123)I]R91150 from single-radiotracer studies: r=0.92, p<0.001 for Method 1, r=0.92, p<0.001 for Method 2, r=0.92, p<0.001, for Method 3. The coefficient describing the ratio of the (123)I-emitted radioactivity at the (125)I-emission spectrum to the radioactivity that it emits at its principal emission spectrum was 0.34 in vivo. Dual-radiotracer in vivo SPECT studies corrected with Method 1 demonstrated a positive correlation between D2/3 and 5-HT2A receptor binding in the rat nucleus accumbens at the voxel level. At the VOI-level, a positive correlation was confirmed in the same region (r=0.78, p<0.01). CONCLUSION: Dual-radiotracer SPECT imaging using (123)I and (125)I-labeled radiotracers is feasible if the cross-talk of (123)I on the (125)I emission spectrum is properly corrected. The most straightforward approach is Method 1, in which a fraction (34%) of the radioactivity emitted from (123)I at its principal energy spectrum is subtracted from the measured radioactivity at the spectrum of (125)I. With this method, a positive correlation between the binding of [(123)I]IBZM and [(125)I]R91150 was demonstrated in the rat nucleus accumbens. This result highlights the interest of dual-radiotracer SPECT imaging to study multiple neurotransmitter systems at the same time and under the same biological conditions. 5-HT(2A) receptor D(2/3) receptor Dual-radiotracer Ibzm Spect Simultaneous SPECT Dewey 616.89 Swiss National Science Foundation Studying the neurochemical determinants of antipsychotic efficacy and side effect profile: a translational dopamine D2 and serotonin 2A receptor neuroimaging approach 156829 CH Project funding 60 Département de psychiatrie 225 false 1250 Imagerie de la transmission dopaminergique dans les troubles addictifs 989 1221 Neuroimagerie moléculaire en psychiatrie 983 NeuroImage 176 34d1c883-93a6-4802-8399-d1ff9843231e Article (Published version) Restricted Tsartsalis-2018.pdf 2134330 application/pdf restrictedAccess Faculté de médecine / Section de médecine clinique / Département de psychiatrie

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Dual-radiotracer translational SPECT neuroimaging. Comparison of three methods for the simultaneous brain imaging of D 2/3 and 5-HT 2A receptors	NeuroImage			2018	577	5

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