X-ray scatter imaging: Cross sections, collimation, speed, and signal extraction

尽管在核磁共振成像、核医学和超声波方面取得了进步，但x射线成像仍然是医学上观察人体内部的主要工具。物理学的创新现在提出了利用x射线捕捉更多信息的新方法。**今天所有的医学x射线成像都使用“主”x射线或透射x射线来形成患者的“阴影”图像。然而，散射x射线占图像接收器辐射的90%，是另一个信息源。我们实验室的重点是开发一种既使用散射又使用初级的x射线成像系统。**我们将：(1)使用卡尔顿大学开发的仪器，完成组织衍射信号库的建立，特别是脑灰质和白质，以及骨代谢示踪剂。(2)继续在萨斯卡通的加拿大光源（CLS）同步加速器上的工作，设计用于x射线散射成像的辐射束（准直）几何形状。我们正在使用CLS的生物医学成像和治疗光束线，其单能光束和辐射仪器为机器开发提供了理想的环境。我们寻求在患者身上与像素化散射检测器串联扫描单个窄波束之间的最佳权衡，这将非常缓慢，但将明确地捕获所有散射信息，而多波束几何形状中的散射模式重叠，这将加快采集速度，但需要使用解缠算法。到目前为止，我们已经用数字探测器演示了五束成像，并成功地解开了纠缠。(3)我们将开始生物医学应用，从骨代谢成像示踪剂和前列腺成像开始。(4)我们将把这一概念应用于医院等标准x射线系统。**这些x射线成像的创新是可商业化的，适用于医学以外的工业无损检测、安全成像和所有其他x射线通过物体照射的领域。一旦基本方法确立，我们将寻求进一步的资金来帮助商业化。****************************

Despite the advances in mri, nuclear medicine, and ultrasound, x-ray imaging remains the main tool used in medicine to look inside the body. Physics innovations now suggest new ways of using x rays to capture more information.** All medical x-ray imaging today uses the "primary" or transmitted x rays to form a "shadow" picture of the patient. Scattered x rays, however, comprise up to 90% of the radiation at the image receptor and are another information source. Our lab's focus is to develop an x-ray imaging system that uses scatter as well as primary.** We will: (1) Complete building a library of diffraction signals of tissues, notably brain grey and white matter, and tracers for bone metabolism, using instrumentation developed at Carleton University. (2) Continue our work at the Canadian Light Source (CLS) synchrotron in Saskatoon to design geometries of the radiation beam (collimation) for x-ray scatter imaging. We are using the BioMedical Imaging & Therapy beamline at CLS, whose monoenergetic beam and radiation instrumentation provide an ideal environment for machine development. We seek the best tradeoff between scanning a single narrow beam in tandem with a pixelated scatter detector over the patient, which will be prohibitively slow but will capture all scatter information unambiguously, versus multibeam geometries in which the scatter patterns overlap, which will speed acquisition but require untangling algorithms to use. So far, we have demonstrated 5-beam imaging with a digital detector and successful disentanglement. (3) We will commence biomedical applications, starting with imaging tracers for bone metabolism, and prostate imaging. (4) We will transfer the concept to standard x-ray systems such as in hospitals.** These innovations in x-ray imaging are commercializable and applicable beyond medicine to industrial nondestructive testing, to security imaging, and to all other areas in which x rays are shone through an object. We will seek further funding to help commercialize once the basic approach has been established.****************************