Speaker
Description
Current positron emission tomography (PET) systems use a high number of readout channels to support high spatial resolution, incurring high cost and complexity. Introducing multiplexed light-sharing readouts reduces the number of necessary channels. However, they suffer from edge effects due to differences in light sharing architecture at the scintillator matrix edge compared to the center, diminishing their spatial resolution and signal-to-noise ratio (SNR). We have developed a single-ended readout depth of interaction (DOI) enabled PET detector with 4-to-1 multiplexing mitigating edge effects. The matrix is coupled to light guides and a silicon photomultiplier (SiPM) array on opposing ends. Multiplexed single-ended readout was achieved by coupling adjacent crystal pairs at the matrix center and distant pairs at the matrix edge. Sharing the scintillation light between exactly two different SiPM pixels enables DOI determination, while pairing distant crystals at matrix edges mitigates edge effects. DOI capability was evaluated using optical simulations. The number of photons incident on the two pixels for a range of DOI was recorded. The number of photons incident on the interaction crystal pixel is always higher than on the connected crystal pixel enabling unambiguous determination of the interaction crystal. The ratio of the number of photons incident on the interaction pixel over the coupled pixel increases exponentially with DOI. Crucially, this property is retained for the edge crystals. The ratio values for both edge and center pairs span three orders of magnitude allowing the presented detector architecture to achieve favorable DOI capability across the entire scintillator matrix.