Fast calibration of SPECT monolithic scintillation detectors using un-collimated sources
Fast calibration of SPECT monolithic scintillation detectors using un-collimated sources
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DOI：
10.1088/0031-9155/58/14/4807
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发表时间：
2013-07-21
影响因子：
3.5
通讯作者：
Vandenberghe, Stefaan
中科院分区：
文献类型：
--
作者：
Espana, Samuel;Deprez, Karel;Vandenberghe, Stefaan
用于正电子发射断层摄影和单光子发射计算机断层摄影（SPECT）成像的单片闪烁探测器与像素化探测器相比具有许多优点。单片晶体的使用允许降低每单位体积的闪烁体成本，并且沿着增加灵敏度以及检测器的能量和定时分辨率。此外，在厚探测器上，可以在没有附加硬件的情况下确定相互作用的深度。然而，已经提出了昂贵且复杂的校准程序来实现单片检测器的最佳检测器性能。这阻碍了它们在商业系统中的使用。因此，需要可以在组装的系统上执行的简单校准例程。这项工作的主要目标是开发一个简化的校准程序的基础上获得的训练数据。与其他使用附加到机器人阶段的束源采集的训练数据的方法相比，所提出的方法使用具有在合理的时间内采集的简单几何形状的静态未准直活动源。一旦获得数据，检测器的校准分三步完成：基于k均值聚类方法的能量校准，基于自组织映射算法的自组织，以及基于Monge-Kantorovich网格自适应的失真校正。使用SPECT探测器对所提出的校准方法进行了2D定位验证。通过与现有的校准方法（最大似然估计）进行比较，获得了类似的结果。总之，我们提出了一种新的单片闪烁探测器的校准方法，大大简化了它们的使用与SPECT系统的最佳性能。
Monolithic scintillation detectors for positron emission tomography and single-photon emission computed tomography (SPECT) imaging have many advantages over pixelated detectors. The use of monolithic crystals allows for reducing the scintillator cost per unit volume and increasing the sensitivity along with the energy and timing resolution of the detector. In addition, on thick detectors the depth-of-interaction can be determined without additional hardware. However, costly and complex calibration procedures have been proposed to achieve optimal detector performance for monolithic detectors. This hampers their use in commercial systems. There is thus, a need for simple calibration routines that can be performed on assembled systems. The main goal of this work is to develop a simplified calibration procedure based on acquired training data. In comparison with other methods that use training data acquired with beam sources attached to robotic stages, the proposed method uses a static un-collimated activity source with simple geometry acquiring in a reasonable time. Once the data are acquired, the calibration of the detector is accomplished in three steps: energy calibration based on the k-means clustering method, self-organization based on the self-organizing maps algorithm, and distortion correction based on the Monge-Kantorovich grid adaptation. The proposed calibration method was validated for 2D positioning using a SPECT detector. Similar results were obtained by comparison with an existing calibration method (maximum likelihood estimation). In conclusion, we proposed a novel calibration method for monolithic scintillation detectors that greatly simplifies their use with optimal performance in SPECT systems.