MR-Compatible X-Ray Tube

描述（由申请人提供）：我们建议研究和设计一种MR兼容的旋转阳极x射线管，该x射线管可以直接与高场1.5T闭孔（CB）磁铁相邻，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射线管与其他已被证实的组件（如数字平板和高频发生器）集成在一起，将使MRI信息能够在x射线图像引导的关键介入程序（如心脏干细胞输送、中风治疗和肝癌管理）中获得。由于移动距离短，仅受磁铁长度的限制，所提出的设计将最大限度地减少患者的移动。这将允许最好地利用血管造影的高分辨率、高对比度和实时成像能力，结合出色的生理评估（血流、灌注、软组织运动）和MRI的3D软组织成像，从而可以评估手术过程中的变化。在此之前，我们成功演示了将静态阳极x射线系统放置在0.5T GE Signa-SP开放式磁体（SP-XMR）的孔中，用于指导一系列具有挑战性的手术，包括新阴道的创建和动静脉畸形的硬化治疗。在约50例患者中，许多患者仅在x光下进行干预并不成功或被认为风险太大；相反，临床医生不可能单独在MR指导下进行干预。紧密集成系统的存在使微创入路成为可能。然而，SP-XMR系统具有适度的x射线输出和专门的磁铁设计，这限制了临床的广泛接受。另一方面，在高场磁体附近操作旋转阳极x射线管会产生重大挑战。因此，我们提出创新研究，开发x射线管子组件，包括新的，磁共振兼容电机和电子光学元件，并具有适当的反馈机制，从而创建一个真正的磁共振兼容旋转阳极x射线管。这种x射线管可以放置在目前可用的最短磁体附近（例如西门子Espree，长度为4英尺），允许x射线和MR之间的视场转换仅为3英尺。这种表平移在x线透视组中经常出现，例如，从腹股沟引导导管进入神经血管。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，然后使用有限元模型作为指导，在已知领域内对组件进行构建和测试。然后将最高效且与MR兼容的组件组合成一个x射线管，并对该管进行测试，以验证该管的输出、焦斑分布和寿命与当前最先进的x射线管相当，用于MR感兴趣的领域范围的荧光检查套件。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.