Magnetic Resonance Systems Development

我们正在解决的问题很容易理解：许多人需要永久或半永久植入的医疗设备(例如起搏器)，其中许多人在生活中的某个时候需要磁共振扫描。由于大多数标准医疗设备要么停止在核磁共振系统中运行，要么在磁共振环境中对受试者构成危险，这些人将没有资格接受核磁共振。这实际上导致了对植入医疗器械的受试者的护理标准较低。联邦政府和各省在医疗成像基础设施方面进行了大量投资，特别是在核磁共振方面。但过去这些超过1.5亿美元的MRI投资，并没有转化为医疗器械行业的明显优势。这是因为，与MR兼容的医疗设备的开发是一个高度复杂的问题，其解决方案需要获得专用设施和适当的专业知识，而这在加拿大目前还没有。该项目最终旨在通过促进更安全、更先进的医疗设备的开发，以改善加拿大人的生活，供更安全、更先进的核磁共振系统使用。出于几个原因，磁共振环境对医疗设备尤其具有挑战性。电磁环境既高度复杂又极端。存在着比地球磁场强数千倍的静态磁场。静磁场的空间梯度导致即使是轻微的磁性材料和物体上也会产生巨大的力和力矩。强烈的时变(kHz，或“音频”)梯度场会导致传导器件发热、电磁干扰以及khz机械振动和扭矩。最后，射频(RF)电场和磁场比人类或设备通常接触到的任何东西都要强得多。暴露在射频场中主要会导致显著的器件发热。射频电磁干扰也可能是控制和通信电路中的问题。我们正在提议建立一个全面的计划，用于研究和开发与MR兼容的医疗设备和更广泛的MR技术。我们已经安装了无与伦比的磁共振扫描仪，涵盖了所有相关领域的优势(从占主导地位的1.5T和3T临床领域优势，到新兴的7T人类使用系统，我们拥有全国唯一的7T系统)。为了使我们成为开发和测试与MR兼容的医疗设备和技术的综合“一站式商店”，我们需要额外的专业能力来：(1)在实验室受控、可重复的条件下重建MR系统中假设会影响任何特定医疗设备的那些方面；(2)对设备操作和对这些实验室暴露环境的反应进行仔细、可重复的测量；(3)在重要的实际MR系统中验证结果。在这项应用中，我们计划在磁共振成像的一般领域培训6名研究生和10名本科生，更具体地说，在MR系统开发和MR兼容医疗设备开发领域。

The problem we are addressing is easy enough to understand: many people need permanently or semi-permanently implanted medical devices (e.g. pacemakers), and many of these people will need an MR scan at some point in their lives. Because most standard medical devices either cease to operate within an MRI system or present a danger to the subject when within the MR environment, these people will not be eligible to receive an MRI. This effectively results in a lower standard of care for subjects with implanted medical devices. The federal government and the provinces have made massive investments in medical imaging infrastructure, particularly in MRI. But these past MRI investments, exceeding $150 million, have not translated into a clear advantage for the medical device industry. This is due to the fact that MR-compatible medical device development is a highly complex problem whose solution requires access to a dedicated facility and appropriate expertise, which is currently absent in Canada. This project ultimately aims to improve the lives of Canadians by facilitating the development of safer, more advanced medical devices for use within safer, more advanced MRI systems. The MR environment is especially challenging for medical devices for several reasons. The electromagnetic environment is both highly complex and extreme. Static magnetic fields thousands of times stronger than Earth’s magnetic field are present. Spatial gradients of the static magnetic fields result in massive forces and torques on even slightly magnetic materials and objects. Strong time-varying (kHz, or “audio frequency”) gradient fields result in heating of conductive devices, electromagnetic interference, and kHz mechanical vibrations and torques. Finally, the radiofrequency (RF) electric and magnetic fields are much more intense than anything humans or devices are normally exposed to. Exposure to RF fields primarily results in significant device heating. RF electromagnetic interference can also be a problem in control and communication circuits. We are proposing to establish a comprehensive program for the research and development of MR-compatible medical devices and MR technology more generally. We already have an unrivaled installation of MR scanners, across all relevant field strengths (from the dominant clinical field strengths of 1.5T and 3T, to the emerging 7T systems for human use, of which we have the only installation in the country). In order for us to be a comprehensive “one-stop-shop” for development and testing of MR-compatible medical devices and technology, we need the additional specialized capacity to: (1) recreate those aspects of the MR system that are hypothesized to affect any given medical device, but under the controlled, reproducible conditions of the laboratory; (2) make careful, reproducible measurements of device operation and reaction to these laboratory exposure environments; (3) validate the results in the actual MR systems of importance. In this application we are proposing to train 6 graduate students and 10 undergraduates in the general area of magnetic resonance imaging, and more specifically in the areas of MR systems development and MR compatible medical device development.