Fast low-dose CT detector for small animal imaging

描述（由申请人提供）： 我们将开发一种快速、低剂量、直接转换的X射线探测器，用于临床前小动物成像。该探测器将改善动物和标本的微CT成像，具有快速读出、减少剂量、高通量和低探测器成本。它可以集成到微型CT系统中，以减少传递给动物的辐射剂量，并将实现由于目前X射线探测器的特性而目前不可行的新程序。微型CT扫描仪已成为研究疾病进展和小动物药物开发不可或缺的一部分。通过将动物研究的便利性与小动物CT的高分辨率相结合，研究速度更快，成本比传统技术更低。功能成像系统（如microPET和microSPECT（1））的制造商也将微型CT探测器集成到其系统中，用于解剖学定位功能活动，执行衰减校正，并实现基于CT的诊断。虽然这些系统可以进行纵向研究，但多个微型CT扫描会向动物提供大量辐射剂量，这可能会干扰预期的实验，甚至杀死受试者。当前的闪烁器-CCD或CMOS光电二极管阵列X射线检测器的剂量效率由于X射线到光的低效转换、光到检测器的传输以及光到电信号的转换而受到损害。我们已经成功地开发了一种新的直接X射线转换材料，多晶碘化汞，这是一种高Z大带隙化合物半导体具有出色的电荷收集性能。建议的探测器是一个薄膜的多晶碘化汞的入射X射线直接转换成电荷，耦合到CMOS读出结构的电荷读出。由于碘化汞薄膜的极高灵敏度，将实现剂量减少和吞吐量提高。我们希望将该设备作为OEM组件广泛销售给扫描仪制造商。在项目的第一阶段，我们将开发晶圆级处理，以适应现有的CMOS读出设备与Hgl 2薄膜，薄膜沉积技术和最终组装测试兼容。在第二阶段，我们将定制CMOS读出芯片的设计，以实现全面优化，根据需要修改Hgl 2沉积，并完成产品原型。探测器原型的第二阶段测试将在Photon Imaging和UCSF的新小动物CT/SPECT系统中进行。

DESCRIPTION (provided by applicant): We will develop a fast, low-dose, direct-conversion x-ray detector for pre-clinical small animal imaging. The detector will improve micro-CT imaging of animal and specimen with fast readout, reduced dose, high throughput, and low detector cost. It can be incorporated into micro-CT systems to reduce the radiation dose delivered to animals and will enable new procedures that are not currently feasible due to the characteristics of present x-ray detectors. Micro-CT scanners have become integral to the study of disease progression and to drug development in small animals. By combining the ease of animal studies with the high resolution of small-animal CT, research is faster and at a lower cost than with conventional techniques. Manufacturers of functional imaging systems such as microPET and microSPECT (1) are also integrating micro-CT detectors into their systems for localizing functional activity anatomically, performing attenuation correction, and for enabling CT-based diagnostics. Although these systems enable longitudinal studies, multiple micro-CT scans deliver a large radiation dose to the animal, which can perturb the intended experiment or even kill the subject. The dose efficiency of current scintillator-CCD or -CMOS photodiode array x-ray detectors is compromised by inefficient conversion of x-rays to light, transport of the light to the detector, and conversion of the light to electric signal. We have successfully developed a new direct x-ray converter material, polycrystalline mercuric iodide, which is a high-Z large bandgap compound semiconductor with outstanding charge collection properties. The proposed detector is a thin film of poly-crystalline mercuric iodide for direct conversion of incident x-rays into charge, coupled to a CMOS readout structure for charge readout. Dose reduction and improved throughput will be achieved due to the very high sensitivity of mercuric iodide films. We expect to widely market the device as an OEM component to scanner manufacturers. In Phase I of the project, we will develop wafer-level processing to adapt an existing CMOS readout device for compatibility with the Hgl2 film, the film deposition techniques, and final assembly testing. In Phase II we will customize the design of the CMOS readout chip for full optimization, modify the Hgl2 deposition as required, and complete a product prototype. Phase II testing of detector prototypes will be performed at both Photon Imaging and UCSF in their new small animal CT/SPECT systems.