Fast Photon-Counting CZT Detector for CT Imaging

项目描述（由申请人提供）：该项目的目标是基于高通量光子计数碲化镉锌（CZT）或碲化镉（CdTe）探测器结合CMOS读出阵列，为CT扫描仪开发下一代x射线计算机断层扫描（CT）探测器模块。与目前所有主要CT制造商使用的技术相比，这项新技术将大大提高诊断能力。目前商业上可用的CT系统通常使用具有硅（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。而不是在一个曝光时间积分x射线电流，高通量光子计数用于测量和计数每个x射线单独在一个类似的周期。高通量是必要的，因为在许多CT应用中使用了非常大的x射线通量。例如，CT扫描仪在未衰减的光束中可以产生~100 m光子/mm2/s。在CT扫描的极短时间内测量传输通量（衰减光束）时，需要大的通量来收集足够的光子统计。这种高计数率与对高检测效率的需求相结合，要求在第一阶段开发探测器结构，提供比整个探测器厚度上载流子的传输时间快得多的响应信号。我们将继续开发具有必要功能的探测器模块，以取代现有的CT探测器技术，并提供新的功能：每个单独的x射线计数（和分析），根据x射线能量对事件进行分组，以及x射线光谱成像功能。这些新特征导致：显著降低患者的x射线剂量，通过x射线光谱成像进行组织成分分析，并可能显著改善整体图像质量。公共卫生相关性：到目前为止，所有商用x射线计算机断层扫描（CT）系统都使用集成探测器。通过将高通量光子计数碲化镉锌或碲化镉探测器与CMOS读出阵列相结合，我们将实现x射线CT性能的重大突破。这些新特征可能会显著降低患者的x射线剂量，通过x射线光谱成像对组织进行成分分析，并可能显著提高整体图像质量。

DESCRIPTION (provided by applicant): The goal of the project is to develop the next generation x-ray computed tomography (CT) detector modules for CT scanners based on high-throughput photon-counting cadmium zinc telluride (CZT) or cadmium telluride (CdTe) detectors combined with CMOS readout arrays. This new technology will deliver significant improvements in diagnostic capabilities compared with the technology currently used by all major CT manufacturers. The currently commercially-available CT systems typically use a detector having silicon (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 an exposure time, high-throughput photon counting is used to measure and count each x-ray individually over a similar period. High throughput is necessary as a very large x-ray flux is utilized in many CT applications. For example, CT scanners can produce ~100 Mphotons/mm2/s in the unattenuated beam. The large flux is required to collect sufficient photon statistics in the measurement of the transmitted flux (the attenuated beam) during the very short time frame of a CT scan. This high count rate combined with a need for high detection efficiency required the development in the Phase I of detector structures that provide a response signal much faster than the transit time of carriers over the whole detector thickness. We will continue the development of detector modules with the necessary capabilities to replace existing CT detector technology and provide new features: 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: 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. PUBLIC HEALTH RELEVANCE: Until now, all commercial x-ray computed tomography (CT) systems have utilized integrating detectors. By combining high-throughput photon-counting cadmium zinc telluride or cadmium telluride detectors with CMOS readout arrays, we will achieve a significant breakthrough in x-ray CT performance. 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.