Radioembolization, a targeted treatment for advanced-stage liver cancer, is a medical procedure in which millions of radioactive microspheres (20–40 µm in diameter) are released into the blood vessels feeding liver tumors. These microspheres not only reduce blood flow to the tumors; their associated radiation kills the cancerous tissues into which they embed. While effective, this procedure also poses a threat to adjacent (non-target) healthy liver tissues. Recent research (both theoretical and experimental) has established a strong relationship between microsphere injection location (in the artery cross section) and the destination vessel, demonstrating the potential for specific vessel and tumor targeting. One such method for positioning the catheter tip, the subject of this research, is to use magnetic levitation. This paper (the second of a two-part series) details the design, fabrication, and preliminary testing of a large air gap magnetic levitator. This device, with a model-based sliding mode controller, is used to precisely position the microcatheter tip in a dynamically perfused arterial model cross section, allowing for microsphere injections from controlled locations within the cross section. Microsphere distributions were found to be significantly dependent on release location, and the large gap levitator is shown to be a viable option for catheter positioning.

中文翻译：

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用于临床微导管的动脉内定位的大型气隙磁悬浮器：设计，制造和初步实验评估

放射性栓塞是晚期肝癌的靶向治疗，是一种医疗程序，其中数百万个放射性微球体（直径20–40 µm）被释放到喂养肝肿瘤的血管中。这些微球不仅减少了流向肿瘤的血液；它们的相关辐射会杀死它们所嵌入的癌组织。虽然有效，但此过程也对相邻（非目标）健康肝脏组织构成威胁。最近的研究（理论和实验）在微球注射位置（在动脉横截面）和目的血管之间建立了密切的关系，证明了特定血管和肿瘤靶向的潜力。一种定位导管尖端的方法是本研究的主题，即使用磁悬浮。本文（由两部分组成的系列文章的第二部分）详细介绍了大气隙磁悬浮器的设计，制造和初步测试。该设备具有基于模型的滑模控制器，用于将微导管尖端精确定位在动态灌注的动脉模型横截面中，从而允许从横截面内的受控位置进行微球注射。发现微球的分布很大程度上取决于释放位置，并且大间隙悬浮剂被证明是导管定位的可行选择。允许从横截面内的受控位置进行微球注射。发现微球的分布很大程度上取决于释放位置，大间隙悬浮器被证明是导管定位的可行选择。允许从横截面内的受控位置进行微球注射。发现微球的分布很大程度上取决于释放位置，大间隙悬浮器被证明是导管定位的可行选择。