Helical Pinhole SPECT for Small-Scale Quantification

用于小规模定量的螺旋针孔 SPECT

• 批准号: 6601242
• 负责人: SCOTT DEAN METZLER
• 金额: $ 15.09万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-04-01 至 2004-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6601242
• 关键词: X ray spectrometry; bioimaging /biomedical imaging; biomedical equipment development; computed axial tomography; computer program /software; computer simulation; computer system design /evaluation; computer system hardware; phantom model; single photon emission computed tomography; technology /technique development

DESCRIPTION (provided by applicant): The overall goal of this project is to develop a SPECT system that utilizes pinhole collimators following helical orbits for quantifying radiotracer distributions in small animals. SPECT imaging is an inexpensive technique for in vivo quantification of various compounds in small-animal models of human disease. The system will combine the excellent properties of pinhole collimators for studying small objects, dramatically increasing magnification and sensitivity at small radius of rotation (ROR), with the sampling properties of helical orbits. Circular pinhole orbits do not completely sample the object of interest leading to sampling artifacts in the subsequent reconstructions; the artifacts worsen as the ROR decreases, causing a trade-off between sampling and both sensitivity and magnification. On the other hand, helical orbits of pinhole collimators allow complete sampling with a small ROR resulting in artifact-free reconstructions from projection data acquired at high sensitivity and magnification. The primary goal of the feasibility (R21) phase is the demonstration of artifact-free reconstructions from helical pinhole projection data. Following the feasibility phase, the system will be further developed to provide quantitative radiotracer distributions. Quantitative SPECT will require both attenuation and scatter compensation. A transmission source will be added to the system to determine the object's attenuation map, a necessary component for attenuation compensation. Some scatter compensation algorithms also utilize attenuation maps. The attenuation map will facilitate the development of software and techniques for attenuation and scatter compensation without the added complexity in the initial phase of integrating an x-ray computed tomography (XCT) system. In addition, the parameters of the helical orbit, in conjunction with the aperture parameters, will be investigated to determine their relationship to the quality of reconstructions. Experimental phantoms will be the primary tool used to evaluate the system's ability to quantify the radiotracer distribution. Software simulations and numerical calculations will complement experimental results. In the longer term, it is desirable to upgrade the spiral pinhole SPECT system with an XCT system to replace the transmission source. The XCT system, when combined with the SPECT system, will provide inherently co-registered SPECT/XCT images that will fuse functional information with anatomical information. Another long-term vision for this system is its miniaturization to a table-top research instrument.

描述（由申请人提供）： 本项目的总体目标是开发一种SPECT系统，该系统利用针孔准直器按照螺旋轨道定量放射性示踪剂在小动物体内的分布。 SPECT成像是一种廉价的技术，用于在人体疾病的小动物模型中体内定量各种化合物。 该系统将联合收割机结合针孔准直仪研究小物体的优良性能，在小旋转半径时大大提高放大率和灵敏度，并具有螺旋轨道的取样性能。 圆形针孔轨道不完全采样感兴趣的对象，导致采样伪影在随后的重建;伪影恶化的ROR降低，导致采样和灵敏度和放大率之间的权衡。 另一方面，针孔准直器的螺旋轨道允许以小的ROR进行完全采样，从而从以高灵敏度和放大率采集的投影数据进行无伪影重建。 可行性（R21）阶段的主要目标是证明螺旋针孔投影数据的无伪影重建。 在可行性阶段之后，将进一步开发该系统，以提供定量放射性示踪剂分布。定量SPECT需要衰减和散射补偿。 将向系统添加传输源以确定对象的衰减图，这是衰减补偿的必要组件。 一些散射补偿算法还利用衰减图。 衰减图将促进衰减和散射补偿的软件和技术的开发，而不会在集成X射线计算机断层扫描（XCT）系统的初始阶段增加复杂性。 此外，螺旋轨道的参数，结合孔径参数，将进行调查，以确定它们的关系，重建的质量。 实验体模将是用于评估系统量化放射性示踪剂分布的能力的主要工具。 软件模拟和数值计算将补充实验结果。从长远来看，希望用XCT系统升级螺旋针孔SPECT系统以取代透射源。 XCT系统与SPECT系统结合使用时，将提供固有的共配准SPECT/XCT图像，该图像将融合功能信息与解剖信息。 该系统的另一个长期愿景是将其小型化为桌面研究仪器。