Redox imaging of tumors with a novel compact and portable EPRI device and its potential for multimodal imaging

The redox state of tumors is involved in cancer cell survival and resistance to therapy, and energy metabolism affects the redox balance. Therefore, an accurate grasping of them is important for effective cancer therapy. Recently, multimodal imaging , which combines different imaging modalities, has attracted much attention. Electron paramagnetic resonance imaging (EPRI) is a method for noninvasively visualization of the redox state by measuring nitroxyl radical probes and creating redox maps showing the reducing power of tissues. Conventional EPRI devices are difficult to combine with PET for metabolic assessment due to their untransferable size. To overcome this problem, we have developed a compact and portable EPRI device. Here, we used this device to compare redox maps of tumors before and after therapy in the same mouse. In addition, we compared the redox maps with autoradiographic images using 2-deoxy-2-[ 18 F]fluoro-D-glucose ([ 18 F]FDG) for application to multimodal imaging with PET.