Optically coupled readout front-end for an MR-compatible PET system

Researchers in the Molecular Imaging Instrumentation Laboratory at Stanford University have developed a PET (positron emission tomography) detector and front end readout assembly that can operate in a high field MRI (magnetic resonance imaging) system. The combined system allows for the sensitive molecular imaging capabilities of PET to be coupled with the detailed anatomical information provided by MR without causing significant mutual interference.

This invention uses a low power front-end circuit to transmit 511 keV photon detector signal information over telecommunications-grade optical fiber to a region that has low magnetic field. By optical conversion of the detector signals and subsequent transmission through fiber, the technology enables construction of a large field of view PET detector gantry inside an MRI system for clinical imaging while minimizing interference. The technology enables simultaneously collected PET and MR data with uncompromised performance.

Stage of Research
The inventors have finalized the "electro-optical" coupled detector design and have begun production of over 1 hundred units that will be arranged in two rings for a prototype high resolution brain imaging PET insert for a 3T MR system. The inventors have also shown that the approach can also produce 250 ps coincidence time resolution with 3x3x20mm LYSO crystal elements, paving the way for whole-body time-of-flight PET/MRI (simultaneous data acquisition), which to date has not been achieved yet.

Ongoing Research
The inventors are continuing to develop the technology and are building a MR- compatible PET system for use in brain imaging, and are also slightly modifying the technology to realize large FOV whole-body time-of-flight PET/MR.