Novel motor design for rotating anode x-ray tubes operating in the fringe field of a magnetic resonance imaging system.
Novel motor design for rotating anode x-ray tubes operating in the fringe field of a magnetic resonance imaging system.
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用于在磁共振成像系统边缘场中运行的旋转阳极 X 射线管的新型电机设计。
DOI：
10.1118/1.4773313
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发表时间：
2013
期刊：
影响因子：
3.8
通讯作者：
Fahrig,Rebecca
中科院分区：
文献类型：
--
作者：
Lillaney,Prasheel;Shin,Mihye;Hinshaw,Waldo;Bennett,NRobert;Pelc,Norbert;Fahrig,Rebecca
目的：在介入手术期间使用混合X射线/MR（XMR）系统进行图像引导可以增强神经系统、肿瘤系统、心血管系统和其他疾病的诊断和治疗。作者提出了一种近距离混合系统设计，其中C形臂透视装置紧邻MR系统的螺线管磁体放置，X射线和MR成像视场之间的最小距离为1.2 m。现有的旋转阳极X射线管设计在MR边缘场环境中失效，因为磁场改变了X射线管中的电子轨迹，并作为感应电机的制动器，降低了阳极的旋转速度。在这项研究中，作者提出了一种新的电机设计，避免了阳极转速reduction.Methods：所提出的设计取代了永磁定子中发现有刷直流电机的径向分量的MR边缘场。X射线管的方向应确保MR边缘场的径向分量与阴极-阳极轴正交。使用反馈位置传感器和作为电滑环的支撑轴承，作者使用电换向来消除对机械电刷和整流器的需要。建议的电机设计的真空兼容的原型组装，并在各种操作条件下的性能进行了评估。原型由3.1英寸的直径为300 kHU的阳极，陶瓷转子为5.6 in.长度为2.9英寸。直径.所有陶瓷部件所选用的材料均为康宁公司开发的可机加工玻璃陶瓷MACOR。整个组件的近似重量为1750 g。研究了电机设计的最大转速、角加速度和加速时间，以及这些参数对转子角偏移、磁场强度和磁场方向的依赖性。作者的组装的谐振特性也进行了评估，以确定其在加速过程中的稳定性，并实施脉冲宽度调制算法来控制motor.Results的旋转速度：在41 mT的磁通密度正交旋转轴（在MR套件中的预期磁通密度的下端）的电机的最大速度被发现是5150转每分钟（rpm）。在59 mT下，达到3000 rpm所需的加速时间约为10 s。具有附接的阳极的组件的共振频率为1310 rpm（21.8Hz），这远低于期望的操作速度。脉宽调制提供了一种有效的方法来控制电机的速度，分辨率为100 rpm。结论：所提出的设计可以直接替代旋转阳极X射线管中使用的传统感应电机。当在MR环境中操作时，其不会遭受降低的旋转速度。原型中铬钢轴承的存在阻止了在更高场强下的测试，未来的设计迭代可以消除这一缺点。原型组件证明了作者设计的概念证明，并克服了MR兼容旋转阳极X射线管的主要障碍之一。
Purpose:Using hybrid x‐ray/MR (XMR) systems for image guidance during interventional procedures could enhance the diagnosis and treatment of neurologic, oncologic, cardiovascular, and other disorders. The authors propose a close proximity hybrid system design in which a C‐arm fluoroscopy unit is placed immediately adjacent to the solenoid magnet of a MR system with a minimum distance of 1.2 m between the x‐ray and MR imaging fields of view. Existing rotating anode x‐ray tube designs fail within MR fringe field environments because the magnetic fields alter the electron trajectories in the x‐ray tube and act as a brake on the induction motor, reducing the rotation speed of the anode. In this study the authors propose a novel motor design that avoids the anode rotation speed reduction.Methods:The proposed design replaces the permanent magnet stator found in brushed dc motors with the radial component of the MR fringe field. The x‐ray tube is oriented such that the radial component of the MR fringe field is orthogonal to the cathode‐anode axis. Using a feedback position sensor and the support bearings as electrical slip rings, the authors use electrical commutation to eliminate the need for mechanical brushes and commutators. A vacuum compatible prototype of the proposed motor design was assembled, and its performance was evaluated at various operating conditions. The prototype consisted of a 3.1 in. diameter anode rated at 300 kHU with a ceramic rotor that was 5.6 in. in length and had a 2.9 in. diameter. The material chosen for all ceramic components was MACOR, a machineable glass ceramic developed by Corning Inc. The approximate weight of the entire assembly was 1750 g. The maximum rotation speed, angular acceleration, and acceleration time of the motor design were investigated, as well as the dependence of these parameters on rotor angular offset, magnetic field strength, and field orientation. The resonance properties of the authors’ assembly were also evaluated to determine its stability during acceleration, and a pulse width modulation algorithm was implemented to control the rotation speed of the motor.Results:At a magnetic flux density of 41 mT orthogonal to the axis of rotation (on the lower end of the expected flux density in the MR suite) the maximum speed of the motor was found to be 5150 revolutions per minute (rpm). The acceleration time necessary to reach 3000 rpm was found to be approximately 10 s at 59 mT. The resonance frequency of the assembly with the anode attached was 1310 rpm (21.8 Hz) which is far below the desired operating speeds. Pulse width modulation provides an effective method to control the speed of the motor with a resolution of 100 rpm.Conclusions:The proposed design can serve as a direct replacement to the conventional induction motor used in rotating anode x‐ray tubes. It does not suffer from a reduced rotation speed when operating in a MR environment. The presence of chromic steel bearings in the prototype prevented testing at the higher field strengths, and future iterations of the design could eliminate this shortcoming. The prototype assembly demonstrates proof of concept of the authors’ design and overcomes one of the major obstacles for a MR compatible rotating anode x‐ray tube.
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介入 X 射线和磁共振成像的兼容性：闭孔 XMR (CBXMR) 系统的可行性。
影响因子：
3.8
作者：
Brzozowski,Lukasz;Ganguly,Arundhuti;Pop,Mihaela;Wen,Zhifei;Bennett,Robert;Fahrig,Rebecca;Rowlands,JA
通讯作者：
Rowlands,JA
旋转阳极 X 射线管。
DOI：
--
发表时间：
1938
期刊：
California and western medicine
影响因子：
--
作者：
R. A. Powers
通讯作者：
R. A. Powers
DOI：
--
发表时间：
1987
期刊：
影响因子：
--
作者：
B. Halliday
通讯作者：
B. Halliday
影响因子：
2.3
作者：
Ray M. Chu;Ramu Tummala;John Kucharczyk;C. Truwit;Robert E. Maxwell
通讯作者：
Robert E. Maxwell
适用于 MR 扫描仪磁场的坚固 X 射线管。
影响因子：
3.8
作者：
Wen,Zhifei;Fahrig,Rebecca;Pelc,NorbertJ
通讯作者：
Pelc,NorbertJ