J Nucl Med. 2012; 53 (Supplement 1):2388
Instrumentation & Data AnalysisMTA II: Instrumentation Posters |
Compressed sensing for the multiplexing of large area silicon photomultiplier PET detectors: Acquisition and calibration
Peter Olcott1,
Ealgoo Kim2,
Garry Chinn2 and
Craig Levin2
1 Bio-engineering, Stanford University, Stanford, CA
2 Radiology, Stanford Medical School, Stanford, CA
Abstract No. 2388
Objectives: Potential clinical silicon photomultiplier based PET systems will consist of tens of thousands of individual sensors. Compressed sensing electronics can be used to multiplex a large number of individual readout sensors to significantly reduce the number of readout channels.
Methods: Using brute force optimization method, a two level sensing matrix based on a 2-weight constant weight code C1[128:32] followed by a 3 weight constant weight code C2[32:16] was designed. These codes consists of discrete resistor elements either connected or not connected to intermediate or output signals. A PET block detector PCB and electronics were fabricated that can multiplex 128 3.2 mm x 3.2 mm solid-state photomultiplier pixels arranged into a 16 x 8 array. Signals from the detector were acquired by a custom 16 channel simultaneously sampling 12-bit 65 Msps ADC acquisition system. Each of the signals was summed to form a trigger, and the peak value for each event on each channel was captured simultaneously. For calibration, we placed a single 4 x 4 array of 3.2 mm x 3.2 mm x 20 mm LYSO crystals onto one of the populated detectors and collected a uniform flood calibration dataset using a 125μCi Ge source. We used a KNN Density clustering method to calculate the centroids of the calibration flood irradiation that were mapped through the sensing matrix and captured by the 16 ADC channels.
Results: All 16 crystals were clearly segmented from the 16 dimensional output data using the new KNN-density clustering method. After correcting for the gain non-uniformities of the SiPM sensor, we measured a preliminary 23.7 +/- 1.2% FWHM energy resolution at 511 keV.
Conclusions: We have successfully fabricated, performed data acquisition, developed a new calibration method, and done preliminary calibration for a compressed sensing PET detector.
Research Support: This work was funded in part by a Stanford SIGF Bio-X Graduate Fellowship
