Time Domian Electron Paramagnetic Resonance Imaging

仪器：我们成功地为EPRI集成了一个通用谐振器组件 在10 mT和MRI在7 T之间利用两种模态之间的300 MHz的公共RF。 有了这种能力，我们已经开发了动物处理和扫描协议， 连续的EPRI和MRI，而无需在扫描之间移动对象。这对于以下方面至关重要： 由于EPRI扫描仪和MRI扫描仪位于大楼的两个角落， 10.所做的研究证明了这些实验的可行性，图像可以 共同注册。此外，MRI方案在实验上和 以计算地导出血流相关特性，从而与所生成的EPRI相关联 pO 2图。一种新的谐振器组件正在设计中，EPRI的工作频率为300 MHz， MHz的MRI，以允许使用3 T MRI进行类似的研究，目前可在附近获得 在同一层楼的EPRI扫描仪。这将使我们能够扩大研究，因为它提供了 额外的MRI时间，这是目前的限制因素。我们还完成了 一个更大尺寸的共振器，直径为7厘米，这将使我们能够获得 关于EPRI在更大尺寸上的可行性的信息，以了解与射频致热相关的问题 和图像保真度。这些信息将有助于评估这项技术对人类的影响 使用.该磁体在最近完成的大孔径尺寸磁体/梯度中进行了测试， 成功地获得了来自所定义对象的图像。我们还增加了 通过结合更灵敏的数字化仪改进信号采集系统。在 在采购软件方面，进行了重大改进，以尽量减少采购系统的间接费用。 - 控制软件，使得能够在更短的时间间隔内获取图像。图像 重建软件也进行了优化，以处理大型数据集与适当的用户 接口，使得图像可以在采集后立即容易地重建， 罐内条件的任何变化都可以立即进行。我们现在正在进行例行的体内实验 多模态肿瘤成像的纵向成像能力的研究，使我们能够 在两周的时间内检查同一只动物，并检查治疗可能对 氧合、血流、代谢状态。

Instrumentation: We have successfully integrated a common resonator assembly for EPRI at 10 mT and MRI at 7 T taking advantage of a common RF of 300 MHz between the two modalities. With this capability, we have developed animal handling and scanning protocols to permit sequential EPRI and MRI without having to move the object between scans. This is critical for the success of the study since the EPRI scanner and MRI scanner are at two corners of Building 10. The studies done demonstrate the feasibility of these experiments and that the images can be co-registered. Additionally MRI protocols were optimized both experimentally and computationally to derive blood flow related properties to correlate with the EPRI generated pO2 maps. A new resonator assembly is being designed to operate at 300 MHz for EPRI and at 128 MHz for MRI to permit similar studies using a 3 T MRI now available in near proximity to the EPRI scanner on the same floor. This will allow us to expand the studies since it gives additional MRI time, which is currently the limiting factor. We also completed construction of a larger size resonator for EPRI with a diameter of 7 cm which will allow us to acquire information on the feasibility of EPRI on larger sizes to learn issues related to RF heating and image fidelity. This information will be valuable in evaluating this technique for human use. This magnet was tested in the recently completed large bore size magnet/gradients and images from defined objects were successfully obtained. We have also made additional improvements in the signal acquisition system by incorporating more sensitive digitizers. In terms of acquisition software, significant improvements were made to minimize overheads in the control software making it possible to acquire images in shorter time intervals. The image reconstruction software is also optimized to handle large data sets with appropriate user interfaces so that images can be readily reconstructed immediately after acquisition so that any changes in the can conditions can be made instantly. We are now conducting routine in vivo studies on multimodality tumor imaging with longitudinal imaging capabilities allowing us to examine the same animal over a two week period and examijne the impact treatments may have on oxygenation, blood flow, metabolic status.