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），其中许多人将在他们生命中的某个时刻需要进行核磁共振扫描。由于大多数标准医疗设备在核磁共振系统中停止工作或在核磁共振环境中对受试者产生危险，因此这些人将没有资格接受核磁共振检查。这有效地降低了对植入医疗设备的受试者的护理标准。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，尤其是核磁共振成像。但过去这些超过1.5亿美元的核磁共振投资，并没有转化为医疗器械行业的明显优势。这是因为兼容核磁共振的医疗装置的开发是一个高度复杂的问题，其解决方案需要使用专用设施和适当的专门知识，而这在加拿大目前是缺乏的。这个项目的最终目的是通过促进开发更安全、更先进的医疗设备，在更安全、更先进的核磁共振成像系统中使用，来改善加拿大人的生活。由于几个原因，MR环境对医疗设备来说尤其具有挑战性。电磁环境是高度复杂和极端的。静态磁场比地球磁场强几千倍。静磁场的空间梯度会对即使是轻微磁性的材料和物体产生巨大的力和力矩。强时变（千赫，或“音频”）梯度场导致导电器件发热、电磁干扰和千赫机械振动和扭矩。最后，射频（RF）电场和磁场比人类或设备通常暴露的任何东西都要强烈得多。暴露于射频场主要导致显著器件发热。射频电磁干扰也可能是控制和通信电路中的一个问题。我们建议建立一个全面的项目来研究和开发兼容核磁共振的医疗设备和更广泛的核磁共振技术。我们已经拥有无与伦比的MR扫描仪安装，涵盖所有相关场强（从占主导地位的1.5T和3T临床场强，到新兴的用于人类使用的7T系统，我们在国内拥有唯一的安装）。为了使我们成为开发和测试核磁共振兼容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：(1)重新创建假设影响任何给定医疗设备的核磁共振系统的那些方面，但在实验室的受控、可复制条件下；(2)对设备操作和对实验室暴露环境的反应进行仔细的、可重复的测量；(3)在实际MR系统中验证结果的重要性。在这个申请中，我们建议在磁共振成像的一般领域培养6名研究生和10名本科生，更具体地说，在磁共振系统开发和磁共振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 developmentof 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 givenmedical device, but under the controlled, reproducible conditions of the laboratory;(2) make careful, reproducible measurements of device operation and reaction to theselaboratory 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.