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

描述(申请人提供)：在过去的十年里，正电子发射断层扫描(PET)通过提供一种临床医生可以接触到的分子成像技术，改变了癌症治疗的方式。通过PET FDG研究，可以定位和描述全身的肿瘤。然而，PET并不能提供高分辨率的解剖信息。因此，几乎所有的正电子发射计算机断层扫描现在都是与X射线计算机断层扫描(CT)一起进行的。最近，磁共振成像也与正电子发射计算机断层扫描相结合，产生补充的分子和解剖数据集。MRI提供了更好的软组织对比度，并有可能获得CT无法提供的各种功能和光谱信息。在PET/CT扫描中，CT通常也占辐射剂量的50%以上。PET/CT研究提供的大约25mSv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。制造能够在磁共振成像的强磁场和射频磁场存在的情况下运行的PET电子设备一直是一个挑战。此外，PET技术应该能够测量光子的“飞行时间”(ToF)，但到目前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)，可用于减少辐射剂量、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功能又与MRI兼容的PET探测器模块。通过用光纤取代电连接，我们假设我们可以将PET信号从MRI孔中发送出来，同时仍然保留光子飞行时间测量所需的计时信息。光纤快速、紧凑、对MRI静电场和射频场的干扰不敏感，并且不需要电气接地。这些光纤可以由专为高速通讯而设计的紧凑型非磁性VCSEL激光器驱动在MRI孔内。定时信息将由异步比较器提取，从而将MRI信号的干扰降至最低。我的目标是构建两个PET探测器模块，从中可以构建一个与MRI兼容的ToF-PET系统。如果成功，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.