Implementation of a Virtual Ring for DOI-Based PET Reconstruction for Open-Field Mouse Brain PET

The Open-Field Mouse Brain PET scanner will facilitate many new neuroscientific studies by enabling the brain of a fully conscious mouse to be imaged as the animal responds to changes in its environment. A key requirement of this system is sub-millimeter spatial resolution throughout the whole field of view, using DOI-based detectors and reconstruction. The DOI reconstruction, however, presents challenges due to the unusual box-shaped geometry of the scanner and the large number of possible LoRs, which makes calculation of the sensitivity matrix time-consuming. Here we present the first results of a virtual ring implementation for computationally efficient DOI-based PET reconstruction. The effects of DOI are observed in the PSFs, with the long tails from the diamond-shaped PSFs being significantly reduced by DOI modeling in the reconstruction. However, further optimization of the virtual ring is needed to achieve the desired spatial resolution.