MR-Compatible X-Ray Tube

描述(申请人提供)：为了最大限度地提高X射线/磁共振混合系统设计的灵活性，我们建议研究和设计一种与MR兼容的旋转阳极X射线管，它可以直接与高场、1.5T闭孔(CB)磁体相邻工作。这种X射线管与其他已经得到验证的组件，如数字平板和高频发生器相结合，将使磁共振成像信息能够在X射线图像引导的关键介入手术中获得，如心脏干细胞输送、中风治疗和肝癌治疗。由于较短的旅行距离仅受磁铁长度的限制，拟议的设计将使患者的旅行减少到最少。这将使血管造影的高分辨率、高对比度和实时成像能力与出色的生理评估(血流、灌注、软组织运动)和MRI的3D软组织成像相结合，从而可以评估手术过程中的变化。此前，我们成功地展示了放置在0.5T GE Signa-SP开放式磁铁(SP-XMR)内孔中的静态阳极X射线系统的临床应用，用于指导一系列具有挑战性的程序，包括创建新阴道和动静脉畸形的硬化治疗。对于约50例患者中的许多病例，仅在X光下进行干预并不成功或被认为风险太大；相反，临床医生不能仅在MR引导下进行干预。紧密集成的系统的存在使微创方法成为可能。然而，SP-XMR系统具有适中的X射线输出和特殊的磁铁设计，这限制了其在临床上的广泛接受。另一方面，在高场磁铁附近操作旋转的阳极X射线管会带来巨大的挑战。因此，我们建议进行创新研究，开发具有适当反馈机制的新型MR兼容电机和电子光学等X射线管子组件，以创建真正与MR兼容的旋转阳极X射线管。该X射线管可以放置在当前可用的最短口径磁铁(例如，西门子Espree，4英尺)附近。长度)允许X射线视场和MR视场之间的平移，仅为三英尺。例如，当引导导管从腹股沟进入神经血管系统时，这种台面平移经常出现在x射线透视套装中。新X射线管的初步研究和设计将包括对电子束和电机组件进行有限元建模，对热分布特性进行建模，然后使用有限元模型作为指导，在已知领域内对组件进行建造和测试。然后，最有效且与MR兼容的部件将被组合成X射线管，并将对该管进行测试，以验证管输出、焦点分布和寿命与当前在荧光透视仪中用于MR感兴趣区域范围的最先进的X射线管相同。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.