Flat-panel X-ray Imaging Detector with Avalanche Gain

描述(由申请人提供)： 该提议的目的是论证基于结构闪烁体-碘化铯(CSL)、增加增益的雪崩非晶硒(a-Se)光导体(我们称为HARP)和有源矩阵(AM)薄膜晶体管(TFT)读出的具有可编程增益的间接平板探测器的可行性，并改善平板X射线成像探测器的低剂量成像性能。我们称正在研究的探测器为SHARP-AMFPI(闪烁器HARP有源矩阵平板成像器)。它将在透视、乳房X光摄影和数字断层合成中提供更好的图像质量，在这些领域，现有的平板探测器无法满足量子噪声的限制。此外，HARP固有的高电场和载流子迁移率允许更好的时间成像性能，从而减少图像伪影和更好的诊断精度。其具体目标是：(1)了解和优化CSL和HARP的基本成像特性，以适应不同的X射线成像应用；(2)使用与优化的CSL层光学耦合的HARP管原型，展示SHARP优异的低剂量和高速性能；(3)识别构建SHARP-AMFPI的潜在实际困难，并开发解决这些困难的工程方法；(4)论证所提议的探测器的实际可行性。我们的研究设计和方法是开发实验和建模技术来研究CSL和HARP的基本成像特性，并用实验结果验证模型的有效性，以便将模型用于优化探测器的设计参数。我们将分三个步骤研究探测器的可行性：首先，利用成熟的HARP电子束读出技术展示雪崩增益对图像质量的优势，然后基于现有的TFT阵列和HARP层沉积技术制作混合原型探测器，以便充分研究这两种器件之间的兼容性问题，最后使用可大规模扩展的程序构建集成的原型探测器，以演示Sharp-AMFPI的最终可行性。它的X射线成像性能将被评估，并与现有的FPI技术进行比较，以便证明其在低剂量和高帧速率下的改进性能。

DESCRIPTION (provided by applicant): The objectives of this proposal are to demonstrate the feasibility of an indirect flat-panel detector with programmable gain based on structured scintillator - cesium iodide (Csl), avalanche amorphous selenium (a-Se) photoconductor (which we call HARP) with increased gain and active matrix (AM) thin film transistor (TFT) readout, and improve the low dose imaging performance of flat-panel x-ray imaging detectors. We call the detector under investigation SHARP-AMFPI (Scintillator HARP Active Matrix Flat Panel Imager). It will provide better image quality in fluoroscopy, behind dense breasts in mammography, and digital tomosynthesis, where existing flat-panel detectors fall short of quantum noise limitation. Furthermore the inherent high electric field and charge carrier mobility in HARP allows better temporal imaging performance which leads to less image artifacts and better diagnosis accuracy. The specific aims are to: (1) understand and optimize the fundamental imaging properties of Csl and HARP for different x-ray imaging applications; (2) demonstrate the excellent low dose and high speed performance of SHARP using a prototype HARP tube optically coupled to optimized Csl layers; (3) identity potential practical difficulties for constructing SHARP-AMFPI and develop engineering methods for solving them; (4) demonstrate the practical feasibility of the proposed detector. Our research design and methods are to develop experimental and modeling techniques to investigate the fundamental imaging properties of Csl and HARP, verify the validity of models with experimental results so that the model can be used to optimize detector design parameters. We will investigate the feasibility of the detector using three gradual steps: First, the advantage of avalanche gain on image quality will be demonstrated using the matured electron beam readout technology for HARP, then a hybrid prototype detector will be made based on existing TFT array and HARP layer deposition technology so that compatibility issues between these two devices can be fully investigated, and finally a integrated prototype detector will be constructed using procedure that is scalable to large areas to demonstrate the ultimate feasibility of SHARP-AMFPI. Its x-ray imaging performance will be evaluated and compared to existing FPI technologies, so that its improved performance at low dose and high frame rates can be demonstrated.