MR-Compatible X-Ray Tube

描述（由申请人提供）：我们提议研究和设计一种MR兼容旋转阳极X射线管，该X射线管可在紧邻高场、1.5T闭孔（CB）磁体的位置运行，以最大限度地提高X射线/MR混合系统设计的灵活性。这种X射线管与其他已经证明的组件（如数字平板和高频发生器）集成，将使MRI信息能够在X射线图像引导的关键介入手术（如心脏干细胞输送、中风治疗和肝癌管理）期间获得。由于仅受磁体长度限制的短行程距离，所提出的设计将最大限度地减少患者行程。这将使血管造影术的高分辨率、高对比度和实时成像能力的最佳利用与MRI的出色生理学评估（血流、灌注、软组织运动）和3D软组织成像相结合，从而可以评估手术期间的变化。之前，我们成功证明了放置在0.5T GE Signa-SP开放式磁体（SP-XMR）孔中的静态阳极X射线系统的临床用途，用于指导一系列具有挑战性的手术，包括创建新阴道和动静脉畸形的硬化治疗。对于约50例患者病例中的许多病例，仅在X线下进行介入治疗并不成功或被认为风险太大;相反，临床医生无法仅在MR引导下进行介入治疗。紧密集成的系统的存在使得微创方法成为可能。然而，SP-XMR系统具有适度的X射线输出和专门的磁体设计，这限制了广泛的临床接受。另一方面，操作邻近高场磁体的旋转阳极X射线管产生重大挑战。因此，我们建议进行创新研究，以开发X射线管子组件，包括新的MR兼容电机和电子光学器件，并具有适当的反馈机制，从而创建真正MR兼容的双阳极X射线管。该X射线管可以被放置在当前可用的最短孔磁体（例如，Siemens Espree，4 ft.长度）允许在X射线和MR的视场之间平移小至三英尺。例如，当引导导管从腹股沟进入神经血管系统时，在X射线透视套件中经常会看到这种床平移。新X射线管的初步研究和设计将包括电子束和电机组件的有限元建模，热分布特性建模，然后使用FE模型作为指导，在已知领域内构建和测试组件。然后将最有效和MR兼容的组件组合到X射线管中，并对该管进行测试，以验证管输出、焦斑分布和寿命是否等同于当前最先进的X射线管，这些X射线管用于感兴趣的MR场范围的荧光透视套件中。这种X射线管将使下一代混合XMR系统成为可能。

DESCRIPTION (provided by applicant): We propose to research and design an MR compatible rotating anode x-ray tube that can function immediately adjacent to a high field, 1.5T closed bore (CB) magnet, in order to maximize flexibility of X-ray/MR hybrid system design. Such an x-ray tube, integrated with other already proven components such as digital flat panel and high-frequency generator, would enable MRI information to be accessible during x-ray image-guided critical interventional procedures such as cardiac stem cell delivery, stroke treatment and liver cancer management. With a short travel distance limited only by the length of the magnet, the proposed design would minimize patient travel. This will allow the best utilization of the high resolution, high contrast and real-time imaging capabilities of angiography to be combined with excellent physiology assessment (flow, perfusion, soft tissue motion) and 3D soft tissue imaging of MRI, so that changes during a procedure can be assessed. Previously we successfully demonstrated the clinical use of a static anode x-ray system placed in the bore of a 0.5T GE Signa-SP open magnet (SP-XMR) for guiding a range of challenging procedures including creation of neo-vagina, and sclerotherapy for arteriovenous malformations. For many of the ~50 patient cases, intervention under x-ray alone had not been successful or was considered too risky; conversely, the clinicians could not have carried out the intervention under MR guidance alone. Presence of the closely integrated system enabled a minimally invasive approach. However, the SP-XMR system has modest x-ray output and a specialized magnet design which restrict wide clinical acceptance. On the other hand, operating a rotating anode x-ray tube adjacent to a high-field magnet produces significant challenges. We therefore propose innovative research to develop x-ray tube sub-components including new, MR compatible motors, and electron optics, with appropriate feedback mechanisms, so as to create a truly MR-compatible rotating-anode x-ray tube. This x-ray tube could be placed adjacent to the shortest bore magnets currently available (e.g. Siemens Espree, 4 ft. in length) allowing a translation between fields-of-view of x-ray and MR of as little as three feet. This table translation is seen often in the x-ray fluoroscopy suite when, for example, guiding catheters from the groin into the neurovasculature. Initial research and design of the new x-ray tube will include finite element modeling of both electron beam and motor components, modeling of heat distribution properties, and then using FE models as a guide, construction and testing of the components within known fields. The most efficient and MR compatible components will then be combined into an x-ray tube, and testing of the tube will be carried out to verify that tube output, focal spot distribution and lifetime are equivalent to current state-of-the-art x-ray tubes used in the fluoroscopy suite for the range of MR fields of interest. This x-ray tube will enable the next generation of hybrid XMR systems.