Image Reconstruction with Solid Srate SPECR

该项目的主要目标是开发和评估用于SPECT（单光子发射计算机断层扫描）的旋转条形伽玛相机的图像重建方法。条形伽玛相机由CdZnTe探测器和钨条准直器组成。这种固态探测器没有光电倍增管，比普通的Anger相机具有更高的能量分辨率（在140 keV光峰时约为3% FWHM）。为了降低CdZnTe材料的成本，探测器采用窄矩形条。而不是使用平行孔准直器，一组平行的板条定义了一系列的平面来准直入射的光子。因此，测量的投影数据是平面积分，而不是传统Anger相机应用中通常遇到的线积分。放射性分布的测量平面积分由一个因子l/r加权，其中r是从感兴趣点到检测器的距离。该方案的一个重要目标是开发能够精确补偿探测器距离相关灵敏度的重建算法。本提案的另一个重要目标是开发算法，使图像免受截断错误。这将使我们的成像系统成为局部层析成像设备。本提案的另一个重要目标是评估新检测器和重建算法组合的性能。特别的重点将放在发展一个新的固态成像系统，将提供几乎无散射和截断错误的图像。采用会聚条形准直器可实现高图像空间分辨率。这项工作有可能显著提高SPECT成像的诊断能力。该提案将(a)促进非常新颖（高风险、高收益）技术的发展，包括继续支持其成熟和充分利用，(b)促进目标应用的技术系统集成，以及(c)通过促进学术界和工业界之间的伙伴关系改善技术转让。

The main objective of this project is the development and evaluation of image reconstruction methods for a rotating, strip gamma camera for SPECT (single photon emission computed tomography). The strip gamma camera consists of a CdZnTe detector and a tungsten slat collimator. This solid-state detector is photomultiplier-tube free and has higher energy resolution (about 3% FWHM at 140 keV photopeak) than a regular Anger camera. In order to reduce the cost of CdZnTe material, the detector is a narrow rectangular strip. Instead of using a parallel-hole collimator, a set of parallel slats that define a series of planes are used to collimate the incoming photons. As a result, the measured projection data are planar integrals as opposed to the line integrals that are generally encountered in traditional Anger camera applications. The measured planar integral of the radioactivity distribution is weighted by a factor l/r, where r is the distance from the point of interest to the detector. One important goal of this proposal is to develop reconstruction algorithms that can exactly compensate for the detectors distance dependent sensitivity. Another important goal of this proposal is to develop algorithms that make the images immune from truncation errors. This will make our imaging system a local tomographic device. Still another important goal of this proposal is to evaluate the performance of the combination of the new detector and reconstruction algorithms. Special emphasis will be placed on developing a novel solid-state imaging system that will provide nearly scatter-free and truncation-error-free images. High image spatial resolution will be achieved by using convergent slat collimators. The work has the potential to significantly improve the diagnostic capabilities of SPECT imaging. This proposal will (a) promote the development of very novel (high risk, high gain) technologies, including continued support for their maturation and full exploitation, (b) promote system integration of technologies for targeted applications, and (c) improve technology transfer by promoting partnerships between academia and industry.