Abstract:
In a combined system, a magnetic resonance (MR) scanner includes a magnet configured to generate a static magnetic field at least in a MR examination region from which MR data are acquired. Radiation detectors are configured to detect gamma rays generated by positron-electron annihilation events in a positron emission tomography (PET) examination region. The radiation detectors include electron multiplier elements having a direction of electron acceleration arranged substantially parallel or anti-parallel with the static magnetic field. In some embodiments, the magnet is an open magnet having first and second spaced apart magnet pole pieces disposed on opposite sides of a magnetic resonance examination region, and the radiation detectors include first and second arrays of radiation detectors disposed with the first and second spaced apart magnet pole pieces.
Abstract:
When designing detector arrays for diagnostic imaging devices, such as PET or SPECT devices, a virtual detector, or pixel, combines scintillator crystals with photodetectors in ratios that deviate from the conventional 1:1 ratio. For instance, multiple photodetectors can be glued to a single crystal to create a virtual pixel which can be software-based or hardware-based. Light energy and time stamp information for a gamma ray hit on the crystal can be calculated using a virtualizer processor or using a trigger line network and time-to-digital converter logic. Additionally or alternatively, multiple crystals can be associated with each of a plurality of photodetectors. A gamma ray hit on a specific crystal is then determined by a table lookup of adjacent photodetectors that register equal light intensities, and the crystal common to such photodetectors is identified as the location of the hit.