Simultaneous PET and MR imaging

Abstract

We have developed a prototype PET detector which is compatible with a clinical MRI system to provide simultaneous PET and MR imaging. This single-slice PET system consists of 48 2 x 2 x 10 mm3 LSO crystals in a 38 mm diameter ring configuration that can be placed inside the receiver coil of the MRI system, coupled to three multi-channel photomultipliers housed outside the main magnetic field via 4 m long and 2 mm diameter optical fibres. The PET system exhibits 2 mm spatial resolution, 41% energy resolution at 511 keV and 20 ns timing resolution. Simultaneous PET and MR phantom images were successfully acquired.

Towards quantitative PET/MRI: a review of MR-based attenuation correction techniques

“…Although preclinical PET/MR prototype systems [10] have been around since the early 1990's, MR-AC is still work in progress. While early preclinical PET/MR design concepts did not include means for AC [6,7], a relatively simple two-class AC scheme was suggested for the first clinical prototype [5].…”

Novel Quantitative Techniques in Hybrid (PET-MR) Imaging of Brain Tumors

“…Initially, intramodality image registration methods were used and were found to be inadequate, which prompted the idea of simultaneous PET-MR prototypes for animal imaging. 11 PET has very high sensitivity for tracking biomarkers in vivo but has poor resolving power for morphology, whereas MR imaging has lower sensitivity, but produces high soft tissue contrast. Combining PET and MR imaging in a single platform to harness the synergy of these 2 modalities is very intuitive and logical.…”

“…Hybrid PET-MR technology was initially developed for imaging small animal models of human disease, 11,12,15,16 and through many years of technical improvements was shown to be feasible in imaging the human brain 17,18 and the whole body. 14,19 Combining PET and MR for simultaneous acquisition of spatially and temporally correlated PET-MR data sets is technically challenging owing to the strong magnetic fields in the MR subsystem.…”

“…5 Biologic brain tumor target volume has shown to be defined more accurately and rationally when 11 C-choline PET is combined with MR imaging. 6 It has been shown that 11 C-choline PET has a higher sensitivity and specificity in distinguishing recurrent brain tumors from radionecrosis compared with 18 F-fluoro-deoxy-glucose ( 18 F-FDG) PET and MR imaging. 7 The diagnostic accuracy can benefit from coregistration of PET and MR imaging, enabling the fusion of high-resolution morphologic images with corresponding biologic information.…”

Whole-body hybrid PET/MRI: ready for clinical use?

“…In the early 1990s Simon Cherry and Paul Marsden saw a need for PET/MR in small-animal imaging studies to combine high soft-tissue contrast with molecular information provided by PET [8,9]. PET/MR was destined to remain in the preclinical arena for another decade until, in 2006, the first simultaneous MR and PET images of the human brain were acquired [10].…”