Back-irradiated flat panel imager with avalanche gain

总结 本计画的目的是发展一种背照式主动矩阵平板显示器 具有可编程雪崩增益的AMFPI成像器。它将具有宽动态范围，高 检测量子效率（DQE）和高帧速率。所提出的检测器采用 三个主要组成部分：结构化碘化铯（CsI）闪烁体，厚度高达 是现有AMFPI的两倍;雪崩非晶硒（a-Se）光电导体， HARP（高增益雪崩冲非晶光电导体），将光 来自CsI的光子充电并提供可编程增益;以及大面积金属氧化物 (MO)薄膜晶体管（TFT）阵列，以每帧100帧的速度电子读取图像 第二次（fps）。建议的探测器被称为BI-SHARP-AMFPI（背辐射闪烁体- HARP有源矩阵平板成像器）。它能够产生x射线量子噪声 X射线成像（0.1 μR）预期最低剂量下的图像有限， 每个像素只有一个X射线光子。对于高剂量应用（例如，射线照相术）， 将降低HARP，以确保宽动态范围，而不会出现探测器饱和。有了BI， 大多数X射线在更靠近光学传感器的地方相互作用，从而允许更厚的CsI 以改善CBCT中使用的高kVp下的DQE。MOTFT中的载流子迁移率大于 比a-Si TFT高一个数量级，允许高达100 fps的读出速率， 在CBCT中，这些目标将通过以下三个具体方面来实现： 目的：（1）优化BI-SHARP-AMFPI探测器配置;（2）开发最佳HARP BI-SHARP-AMFPI的传感器结构;（3）开发原型BI-SHARP-AMFPI，以证明 可行性和验证设计考虑因素。一旦这些目标实现， AMFPI准备临床翻译将产生，并允许重大进展， 最苛刻的X射线成像应用：实时成像和CBCT， 介入手术。

Summary The objective of this proposal is to develop a back-irradiated (BI) active matrix flat-panel imager (AMFPI) with programmable avalanche gain. It will have wide dynamic range, high detective quantum efficiency (DQE) and high frame rate. The proposed detector employs three major components: a structured cesium iodide (CsI) scintillator with thickness up to twice that in existing AMFPI; an avalanche amorphous selenium (a-Se) photoconductor, HARP (High-gain Avalanche Rushing amorphous Photoconductor), to convert the optical photons from CsI to charge and provide a programmable gain; and a large area metal-oxide (MO) thin film transistor (TFT) array to read out the image electronically at 100 frames per second (fps). The proposed detector is called BI-SHARP-AMFPI (Back-Irradiated Scintillator- HARP Active Matrix Flat-Panel Imager). It is capable of producing x-ray quantum noise limited images at the lowest dose expected for x-ray imaging (0.1 μR), which virtually has only one x-ray photon per pixel. For high dose applications (e.g. radiography) the gain of HARP will be decreased to ensure wide dynamic range without detector saturation. With BI, the majority of x-rays interact closer to the optical sensor, thereby permitting much thicker CsI to improve DQE at high kVp used in CBCT. The carrier mobility in MOTFT is more than an order of magnitude higher than a-Si TFT, permitting readout rate up to 100 fps, which is desired in CBCT. The objectives will be accomplished through the following three specific aims: (1) Optimize BI-SHARP-AMFPI detector configuration; (2) Develop the optimal HARP sensor structure for BI-SHARP-AMFPI; (3) Develop prototype BI-SHARP-AMFPI to prove feasibility and validate design considerations. Once these aims are accomplished a new AMFPI ready for clinical translation will be resulted, and permit major advancements in the most demanding x-ray imaging application: real-time imaging and CBCT for guidance of interventional procedures.