title: SPECT-OPT multimodal imaging enables accurate evaluation of radiotracers for β-cell mass assessments.
abstract: Single Photon Emission Computed Tomography (SPECT) has become a promising experimental approach to monitor changes in β-cell mass (BCM) during diabetes progression. SPECT imaging of pancreatic islets is most commonly cross-validated by stereological analysis of histological pancreatic sections after insulin staining. Typically, stereological methods do not accurately determine the total β-cell volume, which is inconvenient when correlating total pancreatic tracer uptake with BCM. Alternative methods are therefore warranted to cross-validate β-cell imaging using radiotracers. In this study, we introduce multimodal SPECT - optical projection tomography (OPT) imaging as an accurate approach to cross-validate radionuclide-based imaging of β-cells. Uptake of a promising radiotracer for β-cell imaging by SPECT, (111)In-exendin-3, was measured by ex vivo-SPECT and cross evaluated by 3D quantitative OPT imaging as well as with histology within healthy and alloxan-treated Brown Norway rat pancreata. SPECT signal was in excellent linear correlation with OPT data as compared to histology. While histological determination of islet spatial distribution was challenging, SPECT and OPT revealed similar distribution patterns of (111)In-exendin-3 and insulin positive β-cell volumes between different pancreatic lobes, both visually and quantitatively. We propose ex vivo SPECT-OPT multimodal imaging as a highly accurate strategy for validating the performance of β-cell radiotracers.
authors.affiliation: Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Wael A
authors.initials: WA
authors.lastname: Eter
authors.affiliation: Umeå Centre for Molecular Medicine, Umeå University, Umeå, Sweden.
authors.forename: Saba
authors.initials: S
authors.lastname: Parween
authors.affiliation: Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Lieke
authors.initials: L
authors.lastname: Joosten
authors.affiliation: Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Cathelijne
authors.initials: C
authors.lastname: Frielink
authors.affiliation: Umeå Centre for Molecular Medicine, Umeå University, Umeå, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Eriksson
authors.affiliation: Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Maarten
authors.initials: M
authors.lastname: Brom
authors.affiliation: Umeå Centre for Molecular Medicine, Umeå University, Umeå, Sweden.
authors.forename: Ulf
authors.initials: U
authors.lastname: Ahlgren
authors.affiliation: Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Martin
authors.initials: M
authors.lastname: Gotthardt
mesh_terms: D000818:Animals; D007205:Indium Radioisotopes / Q000032:analysis*; D007515:Islets of Langerhans / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D064847:Multimodal Imaging; D051381:Rats; D014054:Tomography / Q000379:methods*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
chemical_list: D007205:Indium Radioisotopes