Fast Low-dose CT Detector for Small Animal Imaging

描述(申请人提供)：我们正在开发一种快速、低剂量、直接转换的X射线探测器，用于临床前的小动物成像。该探测器具有读出速度快、剂量小、吞吐量高、成本低等优点，将改善动物和标本的显微CT成像。它可以被结合到微型CT系统中，以减少对动物的辐射剂量，并将使目前由于现有X射线探测器的特点而不可行的新程序成为可能。微型CT扫描仪已经成为研究小动物疾病进展和药物开发的不可或缺的工具。通过结合动物研究的简便性和小动物CT的高分辨率，研究比传统技术更快，成本更低。诸如microPET和microSPECT(1)等功能成像系统的制造商也在将Micro-CT探测器集成到他们的系统中，用于解剖定位功能活动、执行衰减校正以及实现基于CT的诊断。尽管这些系统可以进行纵向研究，但多次微型CT扫描会向动物发出大剂量的辐射，这可能会扰乱预定的实验，甚至会杀死受试者。由于X射线到光的低效转换、光到探测器的传输以及光到电信号的转换，当前闪烁体-ccd或-cmos光电二极管阵列x射线探测器的剂量效率受到影响。我们成功地研制出了一种新的直接X射线转换材料--多晶碘化汞，它是一种具有优异电荷收集性能的高Z大禁带化合物半导体。该探测器是一种多晶碘化汞薄膜，用于将入射X射线直接转换为电荷，并与用于电荷读出的CMOS读出结构相耦合。由于高灵敏度的碘化汞薄膜，剂量的减少和产量的提高将会实现。我们希望将该设备作为OEM组件广泛地销售给扫描仪制造商。在该项目的第一阶段，我们开发了一款专门为兼容Hgl2而设计的专用高速大面积CMOS读出芯片。在第二阶段中，我们将定制用于完全优化的CMOS读出芯片的设计，根据需要修改Hgl2沉积，并完成并测试产品原型。探测器原型的测试将在Gamma Medica和加州大学洛杉矶分校儿童医院的小动物CT/SPECT系统中进行。

DESCRIPTION (provided by applicant): We are developing 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 developed a specialized high-speed large-area CMOS readout chip specially designed for compatibility with Hgl2. In this Phase II we will customize the design of the CMOS readout chip for full optimization, modify the Hgl2 deposition as required, and complete and test a product prototype. Testing of detector prototypes will be performed at both Gamma Medica and UCLA Children's Hospital in their small animal CT/SPECT systems.