Comparisons of [18F]-1-deoxy-1-fluoro-scyllo-inositol with [18F]-FDG for PET imaging of inflammation, breast and brain cancer xenografts in athymic mice

Introduction: The aim of the study was to evaluate the uptake of [F-18]-1-deoxy-1-fluoro-scyllo-inositol ([F-18]-scyllo-inositol) in human breast cancer (BC) and glioma xenografts, as well as in inflammatory tissue, in immunocompromised mice. Studies of [F-18]-2-fluoro-2-deoxy-D-glucose ([F-18]-FDG) under the same conditions were also performed. Methods: Radiosynthesis of [F-18]-scyllo-inositol was automated using a commercial synthesis module. Tumour, inflammation and normal tissue uptakes were evaluated by biodistribution studies and positron emission tomography (PET) imaging using [F-18]-scyllo-inositol and [F-18]-FDG in mice bearing subcutaneous MDA-MB-231, MCF-7 and MDA-MB-361 human BC xenografts, intracranial U-87 MG glioma xenografts and turpentine-induced inflammation. Results: The radiosynthesis of [F-18]-scyllo-inositol was automated with good radiochemical yields (24.6%+/- 3.3%, uncorrected for decay, 65 +/- 2 min, n=5) and high specific activities (>= 195 GBq/mu mol at end of synthesis). Uptake of [F-18]-scyllo-inositol was greatest in MDA-MB-231 BC tumours and was comparable to that of [F-18]-FDG (4.6 +/- 0.5 vs. 5.5 +/- 2.1 %ID/g, respectively; P=.40), but was marginally lower in MDA-MB-361 and MCF-7 xenografts. Uptake of [F-18]-scyllo-inositol in inflammation was lower than [F-18]-FDG. While uptake of [F-18]-scyllo-inositol in intracranial U-87 MG xenografts was significantly lower than [F-18]-FDG, the tumour-to-brain ratio was significantly higher (10.6 +/- 2.5 vs. 2.1 +/- 0.6; P=.001). Conclusions: Consistent with biodistribution studies, uptake of [F-18]-scyllo-inositol was successfully visualized by PET imaging in human BC and glioma xenografts, with lower accumulation in inflammatory tissue than [F-18]-FDG. The tumour-to-brain ratio of [F-18]-scyllo-inositol was also significantly higher than that of [F-18]-FDG for visualizing intracranial glioma xenografts in NOD SCID mice, giving a better contrast. (C) 2011 Elsevier Inc. All rights reserved.