Magnetic induced hyperthermia using thermosensitive ferromagnetic material

使用热敏铁磁材料的磁感应热疗

• 批准号: 16390389
• 负责人: OGAWA Jun-ichi
• 金额: $ 7.81万
• 依托单位: Akita University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16390389/
• 关键词: hyperthermia; Curie point; malignant tumor; thermosensitive magnetic particle; magnetic field; thermal self regulation; 低侵襲; 回転磁場

Background : Magnetic induction heating of thermosensitive material can be used to produce highly localized hyperthermia in deep-seated tumors. The Curie temperature is a transition point at which the development of a particular temperature within the material results in loss of its magnetic properties ; as such, when this temperature is reached, there is cessation of current, and thus heat production stops. Low Curie temperature improves the performance of automatic temperature control throughout the tumor can be achieved by the self-regulating character of thermosensitive materials. We have developed the thermosensitive ferromagnetic particles, which was designed to produce enough heat by eddy current and also to have low Curie point at 43 degrees temperature to provide automatic temperature control.Method : Thermosensitive ferromagnetic particles (diameter : 40-150μm, dose : 500mg) were placed into the 1%-agar and intra-lesional temperatures were measured continuously using ceramics … More thermometer during exposure to magnetic field (600A, 188kHz) by induction heating system.Results : When exposed to magnetic field, these ferromagnetic particles show a sharp rise in the rate of heat production at temperatures at the Curie point in 5 minutes, and the tissue temperature stabilized at the Curie point with good temperature homogeneity throughout the volume heated.Conclusion : This minimally invasive method is attractive for ; 1)constant automatic temperature control in tumor was provided by low Curie point without measuring temperature, 2)the diameter of thermosensitive ferromagnetic particle is 40-100μm, which is larger than capillary blood vessel and lymphatic vessel, particles remain into the injected site, so this method make it possible to be received treatment as outpatients repeatedly without percutaneous puncture every treatment, like RF cauterization. Those results showed that the magnetic induced hyperthermia using thermosensitive ferromagnetic particle, which have low Curie point at 43 degrees temperature to provide automatic temperature control, might be made shift for clinical use in future. Less

背景：热敏材料的磁感应加热可用于在深部肿瘤中产生高度局部的热疗。居里温度是一个转变点，材料内特定温度的发展会导致其磁性损失；因此，当达到该温度时，电流停止，从而停止产生热量。低居里温度提高了整个肿瘤的自动温度控制性能，可以通过热敏材料的自我调节特性来实现。我们开发了热敏铁磁颗粒，其设计目的是通过涡流产生足够的热量，并且在 43 度温度下具有较低的居里点，以提供自动温度控制。方法：将热敏铁磁颗粒（直径：40-150μm，剂量：500mg）放入 1% 琼脂中，使用陶瓷温度计连续测量病灶内温度。 通过感应加热系统暴露于磁场（600A，188kHz）。结果：当暴露于磁场时，这些铁磁颗粒在 5 分钟内表现出居里点温度下的产热速率急剧上升，并且组织温度稳定在居里点，整个受热体积具有良好的温度均匀性。结论：这种微创方法具有吸引力； 1）通过低居里点提供肿瘤内恒定的自动温度控制，无需测量温度，2）热敏铁磁颗粒直径为40-100μm，比毛细血管和淋巴管大，颗粒保留在注射部位，因此该方法可以像门诊患者一样反复接受治疗，而无需像射频烧灼那样每次治疗都经皮穿刺。这些结果表明，使用热敏铁磁颗粒的磁感应热疗，其在43度温度下具有较低的居里点，以提供自动温度控制，未来可能会转向临床使用。较少的