Fast Photon-counting CZT Detector for CT Imaging

项目描述（由申请人提供）：项目目标是基于高通量光子计数碲化镉锌（CZT）探测器与CMOS读出阵列相结合，为x射线CT扫描仪开发下一代CT探测器模块。这项新技术将显著提高诊断能力。我们将开发一种新的检测器模块，与目前所有主要CT制造商使用的技术基本原理相比，它增加了几个新的重要功能。目前商业上可用的CT系统通常使用具有硅（Si） （p-n结）光电二极管的探测器，该探测器与闪烁体光学耦合，闪烁体以电流积分模式工作，其中x射线产生的信号在一段时间内被集成到每个像素中，然后再读取集成电荷。使用这些电流模式检测器的结果通常比使用本产品中提出的技术所能达到的图像质量差。光子计数不是在一段时间内对x射线电流进行积分，而是在类似的时间内对每个x射线进行测量和计数。通过这样做，可以获得以下附加功能：对每个单独的x射线进行计数（和分析），根据x射线能量对事件进行分组，以及x射线光谱成像能力。这些新特征导致：可能显著降低患者的x射线剂量，通过光谱x射线成像进行组织成分分析，并可能显著改善整体图像质量。在第一阶段，我们将为每个单独的像素元素开发和测试漂移结构，以大大提高探测器系统的计数能力，这是由于x射线CT探测器上的大x射线通量入射而产生的关键特性。我们将通过模拟来选择最优结构，然后在高质量的CZT探测器上测量该结构的实际性能。第一阶段的工作将降低第二阶段成功完成的风险，在第二阶段，我们将构建探测器模块原型，该原型将由以（一维或二维）阵列排列的单个探测器模块（瓷砖）组成，从而形成整个探测器。每个探测器模块（瓦片）构成一个像素化的半导体探测器，允许x射线的直接转换。此外，它使用高度先进的下一代集成电路，以产生数字x射线CT图像，其中每个单独的x射线被计数和分析。

DESCRIPTION (provided by applicant): The goal of the project is to develop the next generation CT detector modules for x-ray CT scanners based on high-throughput photon-counting cadmium zinc telluride (CZT) detectors combined with CMOS readout arrays. This new technology will deliver significant improvements in diagnostic capabilities. We will develop a novel detector module which adds several new important features compared with the basic principles of technology currently used by all major CT manufacturers. The currently commercially-available CT systems typically use a detector having silicon (Si) (p-n junction) photodiodes that are optically coupled to a scintillator which is operated in a current-integrating mode where the signals generated from the x-rays are integrated in each pixel over a time before the integrated charge is read out. The use of these current-mode detectors results in generally poorer image quality than could be achieved by using the technology proposed in the product presented here. Instead of integrating the x-ray current over a time, photon counting is used to measure and count each x-ray individually over a similar time. By doing this, the following additional features can be obtained: counting (and analysis) of each individual x-ray, binning events according to x-ray energies, and spectroscopic x-ray imaging capabilities. These new features lead to: potentially significantly reduced x-ray dose to the patient, compositional analysis of tissue through spectroscopic x-ray imaging, and potentially significant improvement in overall image quality. In Phase I we will develop and test a drift structure for each individual pixel element to greatly increase the count-rat capability of the detector system, a critical characteristic due to the large x-ray flux incident on x-ray CT detectors. We will choose an optimal structure by performing simulations and then measuring the actual performance of the structure on high-quality CZT detectors. The Phase I work will reduce the risk for the successful completion of Phase II, where we will construct the detector module prototype which will consist of individual detector modules (tiles) arranged in a (one- or two- dimensional) array so as to form the entire detector. Each detector module (tile) constitutes a pixillated semiconductor detector that allows for direct conversion of the x-rays. In addition it uses highly advanced next generation integrated circuits in order to produce digital x-ray CT images where each individual x-ray is counted and analyzed.