DEVELOPMENT OF A NMR-PET TOMOGRAPHIC SCANNER

核磁共振和正电子发射断层扫描 是目前用于活体研究的补充技术 大脑和心脏组织的解剖和新陈代谢。两者之间的相关性 组织解剖和功能目前是通过获得 PET数据在一台扫描仪上，核磁共振数据在另一台扫描仪上。PET和核磁共振 图像被传输到计算机，在那里它们通常被 受托标记的使用。这种将两者结合在一起的方法 医疗模式可能会导致注册错误以及患者不适 因为这两种成像程序都很耗时。收集核磁共振和 将宠物数据放在一台扫描仪中应该可以解决上述问题。 在磁场中获得PET图像的另一个好处是 是核磁共振所需要的)是预期的空间分辨率的提高 一张PET图像。固有的PET分辨率的物理限制是 由正电子射程和湮没光子的角度偏差定义 它们通常被认为是不可变的。然而，这是有可能的 在强磁场存在的情况下，正电子的作用范围可以受到限制 菲尔德。这一主张的实验证明将消除或显著 减少PET分辨率的基本限制之一。 本次调查的具体目的包括： 一、对仪器的改进，使正电子探测器电子学 不受强磁场的屏蔽或使其不受强磁场的影响。光管 将用于将闪烁晶体耦合到光电倍增管 不受磁场影响的管子。 正电子射程作为正电子能量和正电子能量函数的测量 磁场强度。一个正电子源将被移过一对 探测符合光子的对置准直光子探测器 作为位置的函数。由此得到的LSF(线扩展函数) 数据将被用来确定正电子射程。LSF应该是 如果正电子射程受到磁场的显著影响，则减小。 这项研究将为联合航空公司的发展奠定基础 核磁共振-PET扫描仪。这种装置的好处是提高了分辨率 PET图像，PET和核磁共振数据的关联，无需 信用标记，降低了成本(选址和人员)，因为这两种扫描 都是在同一个单位获得的，减少了患者的不适。

Nuclear magnetic resonance (NMR) and positron emission tomography (PET) are complimentary techniques that are presently used to study in vivo anatomy and metabolism of brain and heart tissues. Correlation between tissue anatomy and functionality is currently accomplished by obtaining PET data on one scanner and NMR data on another scanner. PET and NMR images are transferred to a computer where they are usually overlaid by the use of fiduciary markers. This method of combining the two modalities can lead to registration errors as well as patient discomfort because both imaging procedures are time consuming. Collecting NMR and PET data in one scanner should solve the aforementioned problems. An additional benefit of obtaining PET images in a magnetic field (which is needed for NMR) is the anticipated increase in spatial resolution of a PET image. The physical limitations of intrinsic PET resolution are defined by positron range and angular deviation of annihilation photons which are generally assumed to be immutable. However it is possible that positron range can be limited in the presence of a strong magnetic field. Experimental proof of this claim will remove or significantly reduce one of the fundamental limitations of PET resolution. The specific aims of this investigation include: I. Modification of instrumentation so positron detector electronics are shielded from or made impervious to strong magnetic fields. Lightpipes will be used to couple the scintillation crystals to photomultiplier tubes that are shielded from the magnetic field. II. Measurement of positron range as a function of positron energy and magnetic field strength. A positron source will be moved past a pair of opposed well collimated photon detectors to detect coincidence photons as a function of position. The LSF (Line Spread Function) from this data will be used to determine positron range. The LSF should be reduced if positron range is significantly affected by a magnetic field. This research should lay the foundations for the development of combined NMR-PET scanner. The benefits of such a unit are enhanced resolution of PET images, correlation of PET and NMR data without the need for fiduciary markers, reduced cost (siting and staff) because both scans are acquired in the same unit and less patient discomfort.