Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3E 3P4, Canada.
Phys Med Biol. 2013 Jul 21;58(14):N189-200. doi: 10.1088/0031-9155/58/14/N189. Epub 2013 Jun 25.
An iterative position-weighted centre-of-gravity algorithm was developed and tested for positioning events in a silicon photomultiplier (SiPM)-based scintillation detector for positron emission tomography. The algorithm used a Gaussian-based weighting function centred at the current estimate of the event location. The algorithm was applied to the signals from a 4 × 4 array of SiPM detectors that used individual channel readout and a LYSO:Ce scintillator array. Three scintillator array configurations were tested: single layer with 3.17 mm crystal pitch, matched to the SiPM size; single layer with 1.5 mm crystal pitch; and dual layer with 1.67 mm crystal pitch and a ½ crystal offset in the X and Y directions between the two layers. The flood histograms generated by this algorithm were shown to be superior to those generated by the standard centre of gravity. The width of the Gaussian weighting function of the algorithm was optimized for different scintillator array setups. The optimal width of the Gaussian curve was found to depend on the amount of light spread. The algorithm required less than 20 iterations to calculate the position of an event. The rapid convergence of this algorithm will readily allow for implementation on a front-end detector processing field programmable gate array for use in improved real-time event positioning and identification.
一种迭代的基于权重的质心算法被开发并测试用于正电子发射断层扫描中基于硅光电倍增器（SiPM）的闪烁探测器中的事件定位。该算法使用基于高斯的加权函数，中心位于事件位置的当前估计值。该算法应用于使用单个通道读出和 LYSO：Ce 闪烁体阵列的 4×4 个 SiPM 探测器的信号。测试了三种闪烁体阵列配置：与 SiPM 尺寸匹配的 3.17mm 晶体间距的单层；1.5mm 晶体间距的单层；以及具有 1.67mm 晶体间距的双层，在 X 和 Y 方向上两层之间的晶体偏移为 ½。该算法生成的洪水直方图被证明优于标准质心生成的直方图。该算法的高斯权重函数的宽度针对不同的闪烁体阵列设置进行了优化。发现高斯曲线的最佳宽度取决于光的扩散量。该算法只需不到 20 次迭代即可计算事件的位置。该算法的快速收敛将很容易在前端探测器处理现场可编程门阵列上实现，以用于改进的实时事件定位和识别。
