[Development of a new redox molecular imaging method].

ABSTRACT

For indirect tissue observation, electron-spin, Overhauser-enhanced, dynamic nuclear polarization magnetic resonance imaging (DNP-MRI) is a useful technique. However, its sensitivity and resolution are low compared with the clinical MRI apparatus. By switching to electron spin resonance (ESR) excitation, the magnetic field of the NMR detection, field cycle technique, which aims to improve resolution, was proposed. However, the effect of eddy currents or current value was altered unsatisfactorily. A team at Kyushu University proposed a new DNP-MRI technique capable of improving NMR detection field by preparing in advance a magnetic field, which was connected by the sample transport system. By developing a mobile MRI method that can be used while moving, and fastening the sample in a disk that rotates at a constant speed, they have developed a circular transport DNP-MRI method that greatly reduces the load on the sample. The circular transport DNP-MRI system comprises a circular sample transport system, detection of an MRI magnetic field of 1.5 T, and ESR excitation magnetic field of 20 mT. The developed DNP-MRI had a clear glass tube phantom and resolution of 0.15 mm, and was successful in imaging multiple radical resonant points. It has been commercialized by Japan Redox Limited. In the process of equipment commercialization, a new digital spectrometer has been developed, which expanded the MRI apparatus.