DIGITAL X-RAY IMAGERS BASED ON HGI2 POLYCRYSTALLINE FILM

本提案的目标是开发一种基于Hgl2多晶膜耦合到大面积非晶硅（a- si:H）薄膜晶体管（TFT）寻址读出阵列的数字x射线成像新探测器技术。与利用闪烁荧光粉耦合到a-Si:H读出阵列的探测器相比，这种新型成像探测器在优化后将提供对x射线的灵敏度和优越的空间分辨率的数量级提高。探测器灵敏度的提高将使患者获得同等质量图像的辐射剂量减少10倍。空间分辨率的提高将对图像质量产生直接影响，而图像质量在许多医疗诊断程序（如乳房x线照相术）中具有至关重要的意义。此外，数字能力将允许方便的无胶片图像采集、检索和存储。数字图像处理、计算机辅助诊断以及提供实时图像的能力在许多医学诊断中具有明显的优势。在本提案的第一阶段，我们将开发在厚度、多晶增益尺寸、层均匀性和良好电性能方面高度控制Hgl2薄膜生长的技术。薄膜沉积最初将用1英寸到2英寸见方的样品进行。样品的厚度将从100 - 500微米增长。开发的增长方法将很容易扩展到更大的区域。该工艺将优化为低生产成本。在第二阶段，我们将完成Hgl2胶片的开发，并使用商用面板a- si:H读出器构建大面积（约10“x10”）x射线成像探测器。这种新的x射线成像仪将在我们的实验室和加州大学洛杉矶分校医学院使用狭缝和幻影进行灵敏度、空间分辨率和成像能力的表征。拟议的商业应用：在医学诊断应用、材料的非破坏性评估、生物和其他材料样品的x射线衍射以及天文观测方面，对数字射线照相探测器的应用有着浓厚的兴趣。保守估计，仅在医疗领域，每年每1000人就有800多张x射线图像。由于它们将提供数量级的性能改进，所提出的探测器将对这个巨大的商业市场细分具有很高的吸引力。

The goal of this proposal is to develop a new detector technology for digital x-ray imaging based on Hgl2 polycrystalline films coupled to large area fiat panel amorphous silicon (a-Si:H) thin-film transistor (TFT)addressed readout arrays. This novel Imaging detector when optimized will provide order of magnitude improvements in sensitivity to x-rays and superior spatial resolution compared to detectors utilizing scintillating phosphors coupled to a-Si:H readout arrays. The increased sensitivity of the detector will allow for a ten-old reduction in radiation dose to a patient for an equivalent quality image. The enhancement of the spatial resolution will have a direct impact on the quality of the image1 which has paramount importance in many medical diagnostic procedures such as mammography. In addition, digital capabilities will allow for convenient film-less image acquisition, retrieval, and storage. Digital image processing, computer-assisted diagnosis, and the ability to provide real time images have distinct advantages in many medical diagnostics. During Phase I of this proposal we will develop techniques for highly controlled growth of polycrystalline Hgl2 films In terms of their thickness, sizes of the polycrystalline gains, uniformity of layers and good electrical properties. The film depositions will initially be done with samples ranging from 1" to 2" square. The thickness of the samples will be grown from 1OO-5O0 microm. The developed growth methods will be easily scalable to much larger areas. The process will be optimized for low production cost. In Phase II we will finalize the Hgl2 film development and construct large area (about 10" x10") x-ray imaging detector using a commercial fiat panel a-Si:H readout This new x-ray imager will then be characterized for sensitivity, spatial resolution and imaging capabilities in our laboratory and at UCLA School of Medicine with the use of slits and phantoms. PROPOSED COMMERCIAL APPLICATION: There is a strong interest in application of digital radiographic detectors for medical diagnostic applications, non-destructive evaluation of materials, x-ray diffraction of biological and other material samples, and astronomical observations. Conservative estimates are that in the medical area alone there are over 800 x-ray images produced per 1000 population per year. The proposed detectors will be highly attractive to this enormous commercial market segment due to the order of magnitude performance improvements that they will offer.