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以使用的分子成像技术改变了癌症治疗的方式。通过PET FDG研究，可以定位和表征全身的肿瘤。然而，PET不能提供高分辨率的解剖信息。因此，现在几乎所有的PET扫描都是与x射线计算机断层扫描（CT）一起进行的。最近，MRI也与PET相结合，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，并提供了CT无法提供的各种功能和光谱信息的潜力。CT通常也占PET/CT扫描辐射剂量的50%以上。PET/CT研究提供的大约25mSv可能是一个很大的剂量，特别是对于儿童或需要每年进行PET扫描以检查复发的癌症患者。生产能够在核磁共振成像的强磁场和射频场下工作的PET电子产品一直是一个挑战。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，ToF能力的PET/MRI扫描仪还没有生产出来。ToF可显著提高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与MRI兼容的PET检测器模块。通过用光纤代替电连接，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。光纤速度快，紧凑，对MRI静电场和射频场的干扰不敏感，并且不需要接地。光纤可以通过为高速通信设计的紧凑型非磁性VCSEL激光器驱动到MRI孔内。时序信息将被一个异步比较器拾取，最大限度地减少对MRI信号的干扰。我的目标是构建两个PET检测器模块，从中可以构建mri兼容的ToF-PET系统。如果成功，我们的工作可能会成为一种强大的新型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. PUBLIC HEALTH RELEVANCE: Positron emission tomography (PET) and magnetic resonance imaging (MRI) are medical imaging technologies that have revolutionized the detection and management of cancer; the majority of cancer patients undergo both studies. Combining these scanners will yield a powerful tool for characterizing patient's cancers while significantly reducing the radiation dose given during a PET scan, and improving the accuracy of registering the two data sets. The proposed research will enable state-of- the art time-of-fligh PET performance to be combined with MRI, dramatically improving the signal to noise ratio of PET/MRI systems for significantly enhanced visualization, characterization, and quantification of molecular, anatomical, and physiological signatures of cancer.