Radiology Department, Stanford University, Stanford,CA 94305, USA.
IEEE Trans Med Imaging. 2011 Jul;30(7):1341-52. doi: 10.1109/TMI.2011.2113379. Epub 2011 Feb 10.
In this work, we propose a new method to increase the accuracy of identifying true coincidence events for positron emission tomography (PET). This approach requires 3-D detectors with the ability to position each photon interaction in multi-interaction photon events. When multiple interactions occur in the detector, the incident direction of the photon can be estimated using the Compton scatter kinematics (Compton Collimation). If the difference between the estimated incident direction of the photon relative to a second, coincident photon lies within a certain angular range around colinearity, the line of response between the two photons is identified as a true coincidence and used for image reconstruction. We present an algorithm for choosing the incident photon direction window threshold that maximizes the noise equivalent counts of the PET system. For simulated data, the direction window removed 56%-67% of random coincidences while retaining > 94% of true coincidences from image reconstruction as well as accurately extracted 70% of true coincidences from multiple coincidences.
在这项工作中，我们提出了一种新的方法来提高正电子发射断层扫描 (PET) 中识别真正符合事件的准确性。这种方法需要具有在多相互作用光子事件中定位每个光子相互作用的能力的 3-D 探测器。当探测器中发生多次相互作用时，可以使用康普顿散射运动学 (康普顿准直) 来估计光子的入射方向。如果相对于第二个符合光子的光子的估计入射方向之间的差异在共线性周围的某个角度范围内，则两个光子之间的响应线被识别为真正的符合，并用于图像重建。我们提出了一种用于选择入射光子方向窗口阈值的算法，该算法可以最大化 PET 系统的噪声等效计数。对于模拟数据，该方向窗口去除了 56%-67%的随机符合事件，同时从图像重建中保留了 >94%的真实符合事件，并且还从多个符合事件中准确提取了 70%的真实符合事件。
