High Resolution Mammography Sensor

描述（由申请人提供）：辐射监测设备（“RMD”）正在开发一种基于半导体X射线接收器的数字射线照相成像技术。更具体、更有针对性的应用是乳房X线摄影成像（包括乳房断层合成），稍后将描述该技术的优势。作为这项研究的核心，RMD正在开发制造“直接成像”x射线探测器的工艺，这种探测器是用半导体碘化汞（HgI 2）的多晶层制造的。这项工作的一个重要部分将涉及为预期目的定制这些层的电气，化学和物理特性。为了利用碘化汞作为X射线接收器，它必须与非晶硅（a-Si）薄膜晶体管（TFT）阵列耦合。TFT阵列提供形成完整成像器所需的像素、电荷存储和帧读出。为了使数字乳腺X射线摄影术能够充分发挥其潜力，从而产生重大的临床影响，需要改进X射线检测技术。放射性监测部正在研究一种使用碘化汞（HgI 2）作为X射线探测器的“直接”探测方法。HgI 2薄膜充当传感器，由于其高X射线阻止能力，以高量子效率检测入射的X射线。由于在HgI 2中形成电子-空穴对，所检测的X射线图像被直接转换成电子电荷图像。由于以最小的横向扩展有效地收集这些电荷，该方法不会受到在磷光体中观察到的光扩展效应的影响，从而提供高检测效率以及高空间分辨率。碘化汞具有接近理想的乳腺X射线摄影特性，如高停止效率、大增益、良好的电荷传输和良好的稳定性。最后，RMD提出的存款碘化汞薄膜的方法是高度成本效益，可以用来很容易地覆盖大面积，使其非常互补的大尺寸的a-Si：H TFT阵列，越来越多地成为可用的。RMD计划在两种类型的基板上存款和测试关键的碘化汞层：1）简单的导电板，用于测试电体特性，2）一系列的a-Si TFT阵列，将提供关键的成像数据。RMD将执行与层相关的所有制造任务，并对更简单的器件进行大部分评估。为了帮助a-Si TFT的任务，RMD与两个合作者合作， 瓦里安医疗系统和密歇根大学提供材料和测试专业知识。密歇根大学的Mitchell Goodsitt博士加入了我们的团队，为高分辨率乳腺X射线摄影和数字乳腺断层合成摄影（DBT）的特定成像要求提供指导。MGH的丹尼尔科潘斯和理查德摩尔博士也加入了我们的团队，担任临床顾问。Kopans博士和Richard摩尔是乳腺X线摄影和DBT方面的专家，他们将为临床目标提供指导和意见，并在适用于数字乳腺X线摄影和DBT的条件下对我们的成像仪进行评估。公共卫生相关性：RMD公司正计划开发一种新型的乳腺X射线摄影探测器，该探测器有望在低曝光水平下获得非常高的空间分辨率和上级图像。所提出的制造技术既具有成本效益又易于扩展，这两者都有助于消除可能阻碍技术采用的制造障碍。

DESCRIPTION (provided by applicant): Radiation Monitoring Devices (`RMD') is developing a digital radiographic imaging technology that is based upon a semiconductor x-ray receptor. The more specific, targeted application is mammographic imaging (including breast tomosynthesis) for which the benefits of this technology will later be described. At the core of this research, RMD is developing the process for creating `direct imaging' x-ray detectors fabricated from polycrystalline layers of the semiconductor mercuric iodide (HgI2). A significant part of this work will involve tailoring the electrical, chemical and physical properties of these layers for the intended purpose. To utilize HgI2 as an x-ray receptor, it must be coupled with an amorphous silicon (a-Si) thin film transistor (TFT) array. The TFT array provides pixelation, charge storage and frame readout necessary to form a complete imager. In order to enable digital mammography to achieve its full potential and thereby, have a major clinical impact, x-ray detection technology needs to be advanced. RMD is investigating a `direct' detection method using mercuric iodide (HgI2) as the x-ray detector. The HgI2 film acts as the sensor, detecting the incoming x-rays with high quantum efficiency due to its high x-ray stopping power. The detected x-ray image is converted directly into an electronic charge image due to the formation of electron-hole pairs in HgI2. Due to efficient collection of these charges with minimal lateral spreading, this approach does not suffer from the light spreading effects observed in phosphors and thereby, provides high detection efficiency as well as high spatial resolution. HgI2 has nearly ideal characteristics for mammography such as high stopping efficiency, large gain, good charge transport, and good stability. Finally, the method by which RMD is proposing to deposit the HgI2 films is highly cost effective and can be used to readily cover large areas, making it very complimentary to the large sized a-Si:H TFT arrays that are increasingly becoming available. RMD plans to deposit and test the key HgI2 layers on two types of substrates: 1) simple conductive plates for testing electrical bulk properties, and 2) a range of a-Si TFT arrays that will provide the key imaging data. RMD will perform all the fabrication tasks associated with the layers and conduct most evaluations on the simpler devices. To aid with the a-Si TFT tasks, RMD has joined with two collaborators Varian Medical Systems and the University of Michigan to provide materials and expertise with testing. Dr. Mitchell Goodsitt of the University of Michigan has joined our team to provide guidance on the specific imaging requirements for high resolution mammography and digital breast tomosynthesis (DBT). Dr. Daniel Kopans and Richard Moore of MGH have also joined our team as clinical consultants. Dr. Kopans and Richard Moore are specialists in mammography and DBT and will provide guidance and input on clinical goals and evaluate our imagers under conditions applicable to digital mammography and DBT. PUBLIC HEALTH RELEVANCE: RMD is proposing to develop a new type of mammography x-ray detector that holds the promise of very high spatial resolution and superior images at low exposure levels. The proposed fabrication technique is both cost effective and readily scaleable, both helping to remove manufacturing barriers that can impede adoption of technology.