Superhigh Sensitivity SPECT Imaging with Dense Camera Arrays

描述(由申请人提供)：该项目的长期目标是开发一种新颖的SPECT系统设计，通过在不牺牲成像分辨率的情况下提供极大的提高灵敏度来解决SPECT仪器最有限的方面之一。 该方法基于一种被称为密集摄像机阵列(DCA)的新型检测系统。正如我们已经在SEC中描述的蒙特卡洛研究中所展示的那样。C..2，基于DCA探测器的小动物SPECT系统可以在保持良好的空间分辨率的同时，将光子探测效率提高到1%(而现代临床前SPECT仪器的典型水平为0.1%-0.01%)。这种敏感度的显著提高可能会使我们在临床前和(潜在)临床实践中使用SPECT成像的方式发生根本性的变化，因为它提供了显著降低的检测极限，并允许使用当前一代SPECT仪器难以实施的新成像程序。密集相机阵列(DCA)的设计灵感来自于经常在苍蝇和飞蛾等小型无脊椎动物身上发现的复眼。DCA相机由大量紧密排列的独立微针孔伽马相机元件组成(例如，每平方厘米10-20个独立相机元件)。每个微型摄像元件覆盖穿过物体的狭窄视角。当构建具有多个DCA的SPECT系统时，系统中将有非常大量(多达数千个)的微型相机元件指向对象并同时收集伽马射线。这是在保持良好成像分辨率的同时获得超高检测效率的关键。建造DCA相机的关键挑战之一是需要一种最先进的探测器技术，提供超高的3-D空间分辨率(例如100 mm)、出色的能量分辨率、足够的计数能力和对高能伽马射线的非常高的阻止能力。这将使我们能够将10-20个独立的微型摄像元件放入1平方厘米的面积中，并确保每个微型摄像元件具有足够的分辨率。在这个项目中，我们将利用最近开发的配备混合像素-波形读出系统的小像素CdTe/CZT探测器来构建DCA相机的原型。

DESCRIPTION (provided by applicant): The long-term goal of this project is to develop a novel SPECT system design that tackles one of the most limiting aspects of SPECT instrumentations by offering a greatly improved sensitivity without sacrificing imaging resolution. This proposed approach is based on the use of a novel detection system called dense- camera-array (DCA). As we have demonstrated with a Monte Carlo study described in Sec. C.2, a small animal SPECT system based on the DCA detectors could a photon detection efficiency of >1% (as compared to the typical levels of 0.1%-0.01% found in modern pre-clinical SPECT instrumentations), while maintaining an excellent spatial resolution. This dramatic increase in sensitivity could potentially provide a radical change in how we might employ SPECT imagining in both pre-clinical and (potentially) clinical practice, by offering a dramatically lowered detecton limit and allowing for new imaging procedures that would be difficult to implement with the current generation of SPECT instrumentations. The design of dense camera array (DCA) is inspired by the compound eyes often found on small invertebrates, such as flies and moths. A DCA camera consists of a large number of independent micro-pinhole-gamma- camera-elements closely packed in a dense array (e.g. 10-20 independent camera-elements per cm2). Each of the micro-camera-elements covers a narrow view angular through the object. When constructing a SPECT system with multiple DCAs, there will be a very large number (up to several thousand) of micro-camera- elements in the system pointing towards the object and collecting gamma rays simultaneously. This is the key for attaining a super-high detection efficiency, while maintaining an excellent imaging resolution. One of the key challenges for constructing the DCA camera is the need for a state-of-art detector technology that offers an ultrahigh 3-D spatial resolution (e.g. 100mm), an excellent energy resolution, an adequate count-rate capability and a very high stopping power for energetic gamma rays. This would allow us to pack 10-20 independent micro-camera-elements into 1 cm2 area, and to ensure each micro-camera-element having a sufficient resolving power. For this project, we will utilize a recently developed small-pixel CdTe/CZT detector equipped with a hybrid pixel-waveform readout system to construct the prototype DCA cameras.