Title :
Calibration procedure for a DOI detector of high resolution PET through a Gaussian mixture model
Author :
Yoshida, Eiji ; Kimura, Yuichi ; Kitamura, Keishi ; Murayama, Hideo
Author_Institution :
Nat. Inst. of Radiol. Sci., Chiba, Japan
Abstract :
A depth of interaction detector is developed for the next generation of positron emission tomography (PET) scanners. The detector unit consists of 8 × 8 crystal blocks with four layers of 2 × 2 Gd2SiO5:Ce arrays coupled to a 52 mm square position sensitive photomultiplier tube (PS-PMT). Each scintillation event is mapped in a two-dimensional (2-D) position histogram through the relative ratio of the output signals of the PS-PMT. To facilitate high spatial resolution imaging, accurate crystal identification is needed. A statistical model based on the approach of a Gaussian mixture model (GMM) is introduced for crystal identification. In the GMM, a cluster center and range attributed to individual peaks in the 2-D position histogram are defined. GMM can simultaneously estimate overlapping regions projected each crystal element. After block separation of 8 × 8 on the 2-D distribution, the crystal element regions are identified by the GMM in each block. The GMM method is applied two times, once for the cluster centers and once for determination of the range. These results are used to generate a look-up-table (LUT). This method successfully identified all crystal elements in the clustering area. By Monte Carlo simulation, we also proved that GMM method could choose LUT patterns to high resolution or high sensitivity with one parameter.
Keywords :
Gaussian distribution; Monte Carlo methods; calibration; photomultipliers; position sensitive particle detectors; positron emission tomography; solid scintillation detectors; table lookup; Gaussian mixture model; Gd2SiO5:Ce arrays; Monte Carlo simulation; block separation; calibration procedure; cluster center; clustering area; crystal blocks; crystal element; crystal identification; depth of interaction detector; high resolution PET; high sensitivity; high spatial resolution imaging; look-up-table; output signals; overlapping regions; position sensitive photomultiplier tube; positron emission tomography scanners; scintillation event; statistical model; two-dimensional position histogram; Calibration; Histograms; Photomultipliers; Position sensitive particle detectors; Positron emission tomography; Sensor arrays; Solid scintillation detectors; Spatial resolution; Table lookup; Two dimensional displays; Crystal identification; DOI; GMM; Gaussian mixture model; PET; depth of interaction; position sensitive photomultiplier tube; positron emission tomography;
Journal_Title :
Nuclear Science, IEEE Transactions on
DOI :
10.1109/TNS.2004.835746