Low-Cost, Low-Dose Flat Panel X-ray Detectors with a Novel Semiconductor

项目总结/摘要 在医学成像的几十年的进步之后，基于X射线的成像模态仍然是现代医学成像的支柱。 一般和有针对性的诊断和治疗成像。随着平板探测器技术的出现，平板 平板X射线成像器（FPXI）现在广泛用于数字射线照相、荧光透视、数字断层合成 图像引导放射治疗和锥形束计算机断层扫描。大多数商业FPXI都是 它是基于X射线发生器，依靠X射线到光子，然后到电子信号的间接转换， 较小的部分是基于非晶硒（a-Se）半导体膜，其直接将吸收的X- 射线转换成电子信号间接FPXI在能量上具有高的检测量子效率（DQE） 在感兴趣的范围内（高达140 kVp），并用于大多数平板成像应用。但 光在反射器中的各向同性传播不利地影响所获得的图像的质量， 需要辐射剂量来获得具有可接受的亮度和对比度的图像。另一方面， 的直接转换面板具有出色的空间分辨率和DQE，但由于低电压， 在较高能量下的a-Se吸收率。因此，直接转换FPXI的使用目前仅限于软- 组织应用，主要是乳房X光检查。在本计划中，我们将开发直接转换FPXI， 新型半导体传感器，在高达140 kVp的X射线能量下具有高灵敏度。在第一阶段， 对该半导体X射线传感器进行了评价，在灵敏度，响应线性， 获得电荷传输性能和稳定性。第二阶段计划的重点是示范 基于新型传感器的X射线成像仪，包括适合过渡到临床测试的大面积FPXI， 以及适用于医疗、科研和工业成像应用的可扩展X射线扫描仪模块。

Project Summary/Abstract After decades of advances in medical imaging, X-ray based imaging modalities are still the backbone of modern general and targeted diagnostic and therapeutic imaging. With the advent of flat panel detector technology, flat panel X-ray imagers (FPXIs) are now widely used in digital radiography, fluoroscopy, digital tomosynthesis, image-guided radiation therapy, and cone beam computed tomography. The majority of commercial FPXIs are based on scintillators and rely on indirect conversion of X-rays to photons and then to electronic signals, and a smaller portion is based on amorphous selenium (a-Se) semiconductor films that directly convert absorbed X- rays to an electronic signal. The indirect FPXIs have high detective quantum efficiency (DQE) over the energy range of interest (up to 140kVp) and are used in most of the flat panel imaging applications. However, the isotropic propagation of light in the scintillators adversely affects the quality of obtained images, and high radiation doses are needed to obtain images with acceptable brightness and contrast. On the other hand, a-Se based direct-conversion panels have excellent spatial resolution and DQE, but only up to 40kVp, due to low absorptivity of a-Se at higher energies. Thus, the use of direct-conversion FPXIs is currently limited only to soft- tissue applications, primarily mammography. In this program, we will develop direct-conversion FPXIs with a novel semiconductor sensor with high sensitivity at X-ray energies up to 140kVp. In Phase I, the feasibility of this semiconductor X-ray sensor was evaluated and excellent results in terms of sensitivity, response linearity, charge transport properties, and stability were obtained. The Phase II program is focused on demonstration of X-ray imagers based on the novel sensor, including large area FPXIs suitable for transitioning to clinical testing, and scalable X-ray scanner modules suitable for medical, scientific research, and industrial imaging applications.