High-Sensitivity Photon-Counting X-ray Detector

描述（由申请人提供）：在本阶段II提案中，我们将继续开发一种新型高灵敏度直接转换X射线探测器，该探测器可以彻底改变数字乳腺X射线摄影，因为它将首次允许对单个光子进行计数，从而提高探测性能。到目前为止，所有商业乳房X线摄影系统都使用集成胶片或检测器。通过将高灵敏度探测器材料碘化汞与新的CMOS技术光子计数读数相结合，我们预计能够在X射线探测器性能方面实现重大突破。利用新技术，我们可以通过从信号中基本上去除暗电流和读出电路噪声来实现信噪比的改善。这些因素是决定积分模式检测器灵敏度的特定限制因素。光子计数将减少输送的剂量并提高系统吞吐量，而不会影响图像质量。这在数字乳腺X射线摄影筛查中很重要，因为要检查大量健康患者。我们通过在第一阶段工作中取得的成就降低了第二阶段工作的技术风险：我们制造了与碘化汞化学兼容的大面积（10 cm x 10 cm）成像电荷积分CMOS读出芯片，调整了我们的碘化汞薄膜生长工艺以用于这些芯片，并创建和测试了碘化汞/CMOS X射线成像仪。我们还设计和制造了用于X射线成像应用的专用光子计数ASIC。在第二阶段，我们将采用ASIC设计，并在碘化汞兼容的CMOS芯片中实现，以生产高灵敏度光子计数X射线成像仪。我们将利用我们的设计经验和新开发的CMOS读出技术，使我们能够为阵列中的每个像素放置一个电荷敏感型放大器、整形放大器、双通道鉴别器和数字事件计数器，所有这些都在每个像素的几何区域内。探测器面板原型的性能测试将在DxRay和加州大学戴维斯分校医学中心进行。我们将把该设备作为OEM组件广泛销售给乳腺X射线摄影系统制造商。

DESCRIPTION (provided by applicant): In this Phase II proposal we will continue the development of a novel high-sensitivity direct-conversion x- ray detector that could revolutionize digital mammography because it will for the first time allow counting of individual photons leading to improved detection performance. Until now all commercial mammography systems have utilized integrating film or detectors. By combining a high-sensitivity detector material, mercuric iodide, with newly available CMOS technology photon-counting readouts, we expect to be able to achieve a significant breakthrough in x-ray detector performance. With the new technology we can realize improvement in the signal to noise ratio by essentially removing the dark current and readout circuitry noise from the signal. These factors are the specific limiting factors that determine the sensitivity of integrating mode detectors. Photon counting will reduce the dose delivered and improve the system throughput without compromising image quality. This is important in digital mammography screening due to the large number of healthy patients who are examined. We have reduced the technological risk of the Phase II work by our accomplishments during the Phase I work: We fabricated large area (10 cm x 10 cm) imaging charge-integrating CMOS readout chips which are chemically compatible with mercuric iodide, adapted our mercuric iodide film growth process for use with these chips, and created and tested HgI2/CMOS x-ray imagers. We also designed and manufactured specialized photon-counting ASICs for x-ray imaging applications. During Phase II we will adapt the ASIC design and implement it in the mercuric-iodide-compatible CMOS chips to produce a high-sensitivity photon-counting x-ray imager. We will take advantage of our design experience and newly-developed CMOS readout technology, allowing us to place a charge-sensitive preamplifier, shaping amplifier, dual discriminators, and digital event counter for each pixel in the array, all within each pixel's geometric area. Performance testing of detector panel prototypes will be performed at both DxRay and the University of California, Davis, Medical Center. We will widely market the device as an OEM component to mammography system manufacturers.