Design principles for advanced new low-dose photon-counting x-ray detectors for medical radiography

用于医学放射成像的先进新型低剂量光子计数 X 射线探测器的设计原理

• 批准号: RGPIN-2015-05439
• 负责人: Cunningham, Ian
• 金额: $ 2.19万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=708650
• 关键词: Design; principles; advanced; new; low

X-ray imaging methods have been under development for over 100 years since the discovery of x rays by Röntgen in 1895, and the complete dependency of modern medicine on x-ray-based diagnostic radiography continues to motivate research to improve costs, efficacy, safety and the potential for screening and early diagnoses. However, there are known risks associated with exposure to radiation and it has been estimated that 1 in 200 of all cancer deaths can be attributed to diagnostic x-ray imaging. This critical need to produce better images with less radiation is the driving motivation for this proposal. The ability of a detector to produce high-quality images with low patient exposures is described by the detective quantum efficiency (DQE) of the detector. The DQE is a number between 0 and 1, expressed as a function of spatial frequency, giving performance relative to an ideal detector. Low-frequency DQE values describe how clearly large lesions can be visualized for a given exposure. High-frequency values describe visualization of small structures and fine detail. An improvement in DQE can be used either to increase image quality or reduce patient exposure, depending on the clinical preference. A new generation of detectors is currently under development that can measure the energy of x-ray photons for use in advanced imaging procedures including CT. While it is essential these photon-counting systems be designed to ensure low dose to patients, the tools required to develop optimal designs are primitive and inadequate for the task. As a consequence, we believe some detectors currently under have little chance of success, while others are not being developed to exploit the full potential of advanced applications. The full potential of these new detectors can only be achieved by developing the mathematical tools that relate physical design parameters and materials to the resulting image quality. We will build on previous contributions and the successes of Fourier-based linear systems to develop a cascaded-systems description of signal and noise as it pertains to photon-counting energy-discriminating detectors. We will introduce x-ray photon energy as an independent parameter in a multi-dimensional approach that will, for the first time, accommodate spatial correlations in image signals that result from energy-dependent x-ray interactions. It is these correlations that degrade the DQE of imaging systems, and are ultimately responsible for poor image quality requiring the use of higher radiation exposures to patients. Results from this research will provide the first means to develop optimal detectors for these advanced applications, and to assess and verify their potential to produce high-quality images while maintaining low levels of x-ray exposure to patients.

自1895年Röntgen发现x射线以来，x射线成像方法已经发展了100多年，现代医学完全依赖于基于x射线的诊断放射学，这继续激励着研究，以提高成本、疗效、安全性以及筛查和早期诊断的潜力。然而，已知有与辐射照射有关的风险，据估计，每200例癌症死亡中就有1例可归因于诊断性x射线成像。这种以更少的辐射产生更好的图像的关键需求是该提案的驱动动机。