Investigation of Depth of Interaction Encoding for a Pixelated LSO Array with a Single Multi-Channel PMT.
Investigation of Depth of Interaction Encoding for a Pixelated LSO Array with a Single Multi-Channel PMT.
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DOI：
10.1109/tns.2009.2016094
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发表时间：
2009-10-07
影响因子：
1.8
通讯作者：
Cherry SR
中科院分区：
文献类型：
--
作者：
Yang Y;Wu Y;Cherry SR
研究了一种利用单通道光电倍增管实现像素化LSO阵列相互作用深度编码的新方法。在该方法中，利用LSO元件之间的光学串扰并检查PMT所有通道上的信号的标准偏差（扩展）来估计DOI信息。在Hamamatsu H7546 64通道PMT上对晶体尺寸为1.3×1.3×20 mm 3的未抛光和抛光6×6 LSO阵列进行了评估。将阵列放置在PMT的中心，并将PMT的中心16个通道单独读出并数字化。对于未抛光的阵列，所有晶体都在泛色直方图中分辨。获得了8 mm的平均DOI分辨率。在使用所测量的DOI信息校正信号幅度之后，能量分辨率为± 25%。对于抛光阵列，泛洪直方图上级未抛光阵列，但无法测量DOI信息。使用未抛光的晶体，这种方法可能是一种实用的方法，以实现有限的DOI信息的PET探测器。所有PMT通道的标准偏差可以使用电阻网络轻松获得。只有五个信号（四个信号用于确定x-y位置，一个信号用于测量标准偏差）需要数字化，并且该方法仅需要单个光子检测器来读出阵列。与phoswich探测器不同，该方法不需要将闪烁体阵列分割成层。测得的DOI分辨率比用双端读出方法获得的分辨率差得多，然而，它与用双层phoswich探测器获得的分辨率相似。
A new approach to depth of interaction (DOI) encoding for a pixelated LSO array using a single multi-channel PMT was investigated. In this method the DOI information was estimated by taking advantage of optical crosstalk between LSO elements and examining the standard deviation (spread) of signals on all channels of the PMT. Unpolished and polished 6×6 LSO arrays with a crystal size of 1.3×1.3×20 mm3 were evaluated on a Hamamatsu H7546 64-channel PMT. The arrays were placed on the center of the PMT and the central 16 channels of the PMT were individually read out and digitized. For the unpolished array, all crystals were resolved in the flood histogram. An average DOI resolution of 8 mm was obtained. The energy resolution was ∼25% after the signal amplitude was corrected using the measured DOI information. For the polished array, the flood histogram was superior to the unpolished array, however no DOI information could be measured. Using unpolished crystals, this method could be a practical way to achieve limited DOI information in PET detectors. The standard deviation of all PMT channels can be readily obtained using a resistor network. Only five signals (four signals to determine the x-y position and one signal measuring the standard deviation) need to be digitized, and this method only requires a single photon detector to read out the array. Unlike phoswich detectors, the method does not require segmenting the scintillator array into layers. The measured DOI resolution was much worse than that obtained with the dual-ended readout method, however, it was similar to that obtained with a two-layer phoswich detector.