Electro-optical Approach to Achieve Time-of-Flight PET/MRI for Cancer Imaging

描述（由申请人提供）：在过去的十年中，正电子发射断层扫描（PET）通过提供临床医生可用的分子成像技术改变了癌症的治疗方式。通过PET FDG研究，可以定位和表征全身的肿瘤。然而，PET不提供高分辨率解剖信息。因此，现在几乎所有的PET扫描都与X射线计算机断层扫描（CT）结合进行。最近，MRI还与PET结合，以产生互补的分子和解剖数据集。MRI提供了更好的软组织对比度，并提供了CT无法提供的各种功能和光谱信息。CT通常也占PET/CT扫描中辐射剂量的50%以上。PET/CT研究提供的约25 mSv剂量可能是一个重要的剂量，特别是对于需要每年进行PET扫描以检查复发的儿科或癌症患者。生产可以在MRI的强磁场和射频场存在下工作的PET电子器件一直具有挑战性。此外，PET技术应该能够测量光子“飞行时间”（ToF），但是迄今为止还没有生产出具有ToF能力的PET/MRI扫描仪。ToF显著提高了PET的信噪比（SNR），可用于降低辐射剂量、缩短扫描时间或提高PET分辨率。我的项目旨在开发既具有飞行时间能力又兼容MRI的PET探测器模块。通过用光纤取代电气连接，我们假设我们可以将PET信号发送出MRI孔，同时仍然保留光子飞行时间测量所需的定时信息。光纤快速、紧凑，对MRI的静电场和射频场的干扰不敏感，并且不需要电气接地。这些光纤可以在MRI孔内由专为高速通信设计的紧凑型非磁性VCSEL激光器驱动。定时信息将由异步比较器拾取，最大限度地减少MRI信号的干扰。我的目标是建立两个PET探测器模块，从中可以建立一个MRI兼容的ToF-PET系统。如果成功的话，我们的工作可能成为一种强大的新癌症成像工具的基础。

DESCRIPTION (provided by applicant): Over the past decade positron emission tomography (PET) has changed the way cancer is managed by providing a molecular imaging technique accessible to clinicians. Through PET FDG studies, tumors throughout the body can be located and characterized. PET however, does not provide high resolution anatomical information. As a result almost all PET scans are now performed in conjunction with X-ray computed tomography (CT) scans. Recently, MRI has also been combined with PET to produce complimentary molecular and anatomical data sets. MRI provides better soft tissue contrast and the potential for a wide variety of functional and spectroscopic information not available from CT. CT also typically accounts for over 50% of the radiation dose in a PET/CT scan. The approximately 25mSv delivered by a PET/CT study can be a significant dose, especially for pediatric, or cancer patients who require annual PET scans to check for recurrence. Producing PET electronics that can operate in the presence of the MRI's strong magnetic and radio frequency fields has been challenging. In addition, the PET technology should be capable of measuring photon "time- of-flight" (ToF), but to date ToF capable PET/MRI scanners have not been produced. ToF significantly increases the signal to noise ratio (SNR) of PET, which can be used to decrease radiation dose, decrease scan time, or increase PET resolution. My project aims to develop PET detector modules that are both time-of-flight capable and MRI compatible. By replacing electrical connections with optical fibers, we hypothesize that we can send PET signals out of the MRI bore while still preserving the timing information necessary for photon time-of-flight measurements. The optical fibers are fast, compact, insensitive to interference from MRI's static and RF fields, and do not require electrical grounding. The fibers can be driven inside the MRI bore by compact non-magnetic VCSEL lasers designed for high speed telecommunications. Timing information will be picked off by an asynchronous comparator, minimizing interference of the MRI signal. My goal is to build two PET detector modules from which an MRI-compatible, ToF-PET system can be built.. If successful, our work could be the basis for a powerful new cancer imaging tool.