Time Domian Electron Paramagnetic Resonance Imaging

项目1：时域电子顺磁共振成像： 在氧含量范围为0%（缺氧）至21%（常氧）的规定条件下，使用含有三苯甲基造影剂Oxo 63、Oxo 31和Oxo 71的体模样本，通过时域电子顺磁共振成像（EPRI）对氧成像进行了确认。对这些样品进行的成像实验显示出光谱响应，这与氧含量一致。 随后，对梯度大小、视场、成像时间和图像分辨率等成像实验条件进行了研究，得出了最佳的活体成像实验条件。对诸如荷瘤小鼠的活体动物的研究表明，肿瘤和诸如肾、心脏、肝脏等的正常器官积累了显著水平的造影剂，并且造影剂分布的图像提供了足够的图像强度以提取生理信息。 关于仪器，扫描仪现在已经具备使用具有纳秒时间分辨率的成形RF脉冲提供均匀RF激励的能力。此外，数据采集系统现已开发，以提供快速数据采集的能力，使得现在可以在不到5分钟的时间内收集具有亚毫米空间分辨率的三维图像。 有了这些能力，体内实验可以进行高时间和空间分辨率。数据分析程序，以提取空间共注册的功能信息，现在正在测试，使常规的体内研究可以进行。

Project 1: Time Domian Electron Paramagnetic Resonance Imaging: The validation of oxygen imaging by Time Domain Electron Paramagnetic Resonance Imaging (EPRI) has been validated using phantom samples containing the trityl contrast agents Oxo 63, Oxo 31, and Oxo 71 under defined conditions of oxygen content in the range of 0% oxygen (anoxia) to 21 % oxygen (normoxia). Imaging experiments carried out on these samples showed spectral responses, which were in agreement with the oxygen content. Subsequently, experimental conditions in imaging studies such as the gradient magnitudes, field of view, imaging times and image resolution were studied and optimal conditions were arrived at for in vivo imaging experiments. Studies on live animals such as tumor bearing mice suggest that tumors and normal organs such as kidneys, heart, liver etc accumulate significant levels of the contrast agent and images of the contrast agent distribution provides enough image intensity to extract physiological information. With respect to instrumentation, the scanner has been now provided with capabilities to provide uniform RF excitation using shaped RF pulses with nanosecond time resolution. Additionally, data acquisition system has now been developed to provide capabilities for rapid data acquisition making it now possible to collect three-dimensional images with sub-mm spatial resolution in less than 5 minutes. With these capabilities, in vivo experiments can be carried out with high temporal and spatial resolution. Data analyses procedures to extract spatially co-registered functional information are now being tested so that routine in vivo studies can be performed.