Advanced detector technology for Digital Breast Tomosynthesis

x射线成像探测器依赖于x射线量子到电子信号的间接或直接转换，在商业系统中最常用的是间接方法。在这种情况下，多阶段转换过程从闪烁体将x射线量子转换为光子开始。光子依次扩散通过荧光粉，然后被一组光电二极管转换成电子。在直接方法中，x射线量子被光导体吸收，直接产生电子空穴对。电子空穴对被偏置场分开，在成像阵列中产生电子信号。直接转换的固有优点是：(a)高空间分辨率，(b)将剂量效率提高到最低所需的辐射暴露，以及(c)直接转换探测器系统更简单，因此由于避免了对单独集成的光电二极管的需要，因此可能更经济地制造。数字x射线成像的理想应用包括高分辨率低剂量高分辨率x射线成像，如数字乳腺断层合成（DBT），这是一种先进的乳腺癌成像技术，已经出现，以解决标准二维乳房x光检查对大量患者不确定的性质。NSERC联盟基金的目标是开展材料科学研究，研究基于两种不同多晶型氧化铅（PbO）光导体的新型x射线光导结构，用于直接转换x射线探测器，并证明PbO技术用于DBT应用的技术可行性。与现有的商业方法相比，PbO光导体新技术将实现更高的灵敏度和更高的空间分辨率。我们创新的辐射医学探测器方法提高了癌症检测的诊断能力和效率，同时减少了与辐射医学成像相关的剂量。因此，加拿大公民和世界各地的其他个人将受益于高质量和辐射安全的诊断成像。

X-ray imaging detectors rely on indirect or direct conversion of x-ray quanta to an electron signal, with the indirect method most commonly on commercial systems. In this case the multi-stage conversion process begins with a scintillator converting x-ray quanta into optical photons. The optical photons in turn diffuse through a phosphor and then are converted to electrons by an array of photodiodes. In the direct method, the x-ray quanta are absorbed in a photoconductor that directly creates electron hole pairs. The electron hole pair is separated by a bias field to generate an electron signal in the imaging array. The advantages inherent in direct conversion are: (a) high spatial resolution, (b) improved dose efficiency down to the lowest required radiation exposure, and (c) the direct conversion detector system is simpler, and hence potentially more economical to manufacture since the need for separately integrated photodiodes is avoided. Applications in digital x-ray imaging that are ideal for this technology include high resolution low-dose high-resolution x-ray imaging, such Digital Breast Tomosynthesis (DBT), which is an advanced breast cancer imaging technique that has emerged to address the inconclusive nature of standard 2D mammography for a large group of patients.The goals of this NSERC Alliance Grant is to undertake material science research into a new x-ray photoconductive structure based on two different polymorphs of lead oxide (PbO) photoconductor for direct conversion x-ray detectors, and to demonstrate the technical feasibility PbO technology for DBT applications. The new technology of PbO photoconductors will achieve higher sensitivity and improved spatial resolution compared to existing commercial methods. Our innovative approach to radiation medical detector improves the diagnostic capabilities and efficiencies of cancer detection, while reducing the dose associated with radiation medical imaging. As a result, the citizens of Canada and other individuals world-wide, will benefit from high quality and radiation-safe diagnostic imaging.