双平板多功能核医学成像系统数据校正算法研究

发布时间：2018-02-10 19:09

本文关键词： 双平板 PET γ相机归一化校正几何校正　出处：《东华理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：正电子发射断层成像(Position Emission Tomography,PET)与单光子发射计算机断层成像(Single Photon Emission Computed Tomography)作为两种目前应用最为广泛的核医学成像技术,通过将放射性药物注入人体内,在获取生命体的部分器官的代谢中有着强大的优势,可以为一系列重大疾病的早期诊断及疗效评估提供信息。双平板多功能核医学成像设备作为兼具两种成像模式,采用平板探测器结构,真正实现“一机多用”,具有探测条件灵活,适用场景多样,灵敏度高等优势,有益于临床应用和推广。本论文完成双平板多功能核医学成像系统开展的主要研究工作如下:针对影响图像质量的多种因素进行深入研究与探讨,包括系统探测效率不均匀,以及γ相机成像工作模式下的几何偏移与探测器响应不一致等。对影响图像质量的物理因素和数据的统计特性进行深入研究。PET工作模式下,探测器系统响应一致性主要受到几何效率、本征效率和光子穿过晶体条的有效距离等因素的影响,通过对这些因素的分析,提出了一种基于变量分离技术的归一化校正算法。该方法将几何因素与其他因素剥离,与后续图像重建环节实现无缝衔接,有效地缓解了探测效率不均匀对图像质量的影响,且具有实验方案简洁易行等特点。γ相机工作模式下,细致分析了几何偏移对成像效果的影响,根据应用场景需求,设计了一套几何参数校正算法,该方法通过一系列几何参数建立了投影空间和物体空间的准确映射关系,采用几何参数对探测器在轴向发生的旋转、偏移和倾斜等几何误差和投影数据的坐标关系进行建模,提出了点源移动检测技术方案,通过提取以上几何参数的误差值,优化图像质量。本论文完成双平板多功能核医学系统在两种工作模式下的校正算法的设计与开发,基于GATE模拟对系统进行评价与测试,并将校正算法应用于设备中。
[Abstract]:Positron emission tomography (PET) and single Photon Emission Computed tomography (SPECT) are two of the most widely used nuclear medical imaging techniques, by injecting radioactive drugs into human body. It can provide information for the early diagnosis and evaluation of a series of major diseases. The dual-plate multifunctional nuclear medical imaging device has two imaging modes, and has a strong advantage in obtaining the metabolism of some organs of the living body, and it can provide information for the early diagnosis and evaluation of the curative effect of a series of major diseases. With the flat panel detector structure, the "one machine multipurpose" is realized, which has the advantages of flexible detection conditions, various applicable scenes, high sensitivity, and so on. This paper is beneficial to clinical application and popularization. The main research work of this paper is as follows: the factors that affect the image quality, including the uneven detection efficiency of the system, are studied and discussed in detail. And the geometric migration in 纬 camera imaging mode is not consistent with the detector response. The physical factors affecting the image quality and the statistical characteristics of the data are studied in detail under the working mode of PET. The response consistency of the detector system is mainly affected by geometric efficiency, intrinsic efficiency and effective distance of photons passing through the crystal strip. In this paper, a normalized correction algorithm based on variable separation technique is proposed, in which geometric factors are separated from other factors and connected seamlessly with subsequent image reconstruction, which effectively alleviates the effect of uneven detection efficiency on image quality. The effect of geometric migration on imaging effect is analyzed in detail, and a set of geometric parameter correction algorithm is designed according to the requirements of the application scene. Based on a series of geometric parameters, the accurate mapping relationship between projection space and object space is established, and the geometric errors such as rotation, offset and tilt of the detector in the axial direction and the coordinate relation of the projection data are modeled by geometric parameters. A point source moving detection scheme is proposed to optimize the image quality by extracting the error values of the above geometric parameters. In this paper, the design and development of the correction algorithm for the dual-plate multifunctional nuclear medicine system in two working modes are completed. The system is evaluated and tested based on GATE simulation, and the calibration algorithm is applied to the equipment.
【学位授予单位】：东华理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R817;TP391.41

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