Simultaneous imaging of magnetic resonance imaging and positron emission tomography by means of MRI-compatible optic fiber-based PET: A validation study in ex vivo rat brain

Purpose: We developed a new type of scintillation detector ring for positron emission tomography (PET). In this device the scintillation detectors were connected with 2.6 m length optic fibers to transport scintillation light to a photomultiplier (PMT) located apart from the detector rings. The present study aimed to test the possibility of simultaneous imaging with PET and magnetic resonance imaging (MRI) by means of the present PET device in ex vivo rat brain. Materials and methods: The scintillation detector ring of 4 cm diameter was located in a magnetic field of 0.15 T open MRI. Simultaneous measurements of PET and MRI were performed in ex vivo rat brain after injection of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) 37 MBq and ¹⁸F-NaF 37 MBq. Simultaneous data acquisition was performed for 10 min for PET and 5 min for T1-weighted MRI. Results: Simultaneous imaging of PET and MRI was possible without noticeable image distortion in the PET and MRI scans. In the fusion images, high uptake of ¹⁸F-FDG was identified in the Harderian glands and striatum. High uptake of ¹⁸F-NaF was found in the skull base and vault. Conclusions: The present study indicated the possibility of simultaneous imaging of PET and MRI by means of optic fiber-based scintillation detectors.