Parizh Michael, Lvovsky Yuri, Sumption Michael
General Electric Global Research.
General Electric Healthcare.
Supercond Sci Technol. 2017 Jan;30(1):014007. doi: 10.1088/0953-2048/30/1/014007. Epub 2016 Nov 16.
Magnetic Resonance Imaging (MRI), a powerful medical diagnostic tool, is the largest commercial application of superconductivity. The superconducting magnet is the largest and most expensive component of an MRI system. The magnet configuration is determined by competing requirements including optimized functional performance, patient comfort, ease of siting in a hospital environment, minimum acquisition and lifecycle cost including service. In this paper, we analyze conductor requirements for commercial MRI magnets beyond traditional NbTi conductors, while avoiding links to a particular magnet configuration or design decisions. Potential conductor candidates include MgB, ReBCO and BSCCO options. The analysis shows that no MRI-ready non-NbTi conductor is commercially available at the moment. For some conductors, MRI specifications will be difficult to achieve in principle. For others, cost is a key barrier. In some cases, the prospects for developing an MRI-ready conductor are more favorable, but significant developments are still needed. The key needs include the development of, or significant improvements in: (a) conductors specifically designed for MRI applications, with form-fit-and-function readily integratable into the present MRI magnet technology with minimum modifications. Preferably, similar conductors should be available from multiple vendors; (b) conductors with improved quench characteristics, i.e. the ability to carry significant current without damage while in the resistive state; (c) insulation which is compatible with manufacturing and refrigeration technologies; (d) dramatic increases in production and long-length quality control, including large-volume conductor manufacturing technology. In-situ MgB is, perhaps, the closest to meeting commercial and technical requirements to become suitable for commercial MRI. Conductor technology is an important, but not the only, issue in introduction of HTS / MgB conductor into commercial MRI magnets. These new conductors, even when they meet the above requirements, will likely require numerous modifications and developments in the associated magnet technology.
磁共振成像（MRI）是一种强大的医学诊断工具，是超导性在商业上的最大应用。超导磁体是MRI系统中最大且最昂贵的组件。磁体配置由相互竞争的要求决定，这些要求包括优化的功能性能、患者舒适度、在医院环境中易于安装、包括服务在内的最低购置和生命周期成本。在本文中，我们分析了除传统铌钛（NbTi）导体之外的商用MRI磁体的导体要求，同时避免与特定的磁体配置或设计决策产生关联。潜在的导体候选材料包括MgB、稀土钡铜氧（ReBCO）和铋锶钙铜氧（BSCCO）等选项。分析表明，目前尚无适用于MRI的非NbTi商用导体。对于某些导体，原则上很难达到MRI的规格要求。对于其他一些导体，成本是关键障碍。在某些情况下，开发适用于MRI的导体的前景较为乐观，但仍需要重大进展。关键需求包括开发或大幅改进以下方面：（a）专门为MRI应用设计的导体，其形状、配合和功能应能以最小的修改轻松集成到当前的MRI磁体技术中。最好有多个供应商能提供类似的导体；（b）具有改进失超特性的导体，即在电阻状态下能够承载大电流而不损坏的能力；（c）与制造和制冷技术兼容的绝缘材料；（d）大幅提高生产和长长度质量控制，包括大批量导体制造技术。原位MgB可能是最接近满足商业和技术要求从而适用于商用MRI的材料。导体技术是将高温超导（HTS）/MgB导体引入商用MRI磁体的一个重要但并非唯一的问题。即使这些新导体满足上述要求，相关磁体技术可能仍需要进行大量修改和开发。
