引导超声聚焦热消融的超高场磁共振射频电磁场匀场技术及人体组织比吸收率安全分析

发布时间：2018-02-22 14:05

本文关键词： 高强度聚焦超声超高场匀场策略比吸收率时域有限差分算法　出处：《南方医科大学学报》2014年10期 　论文类型：期刊论文

【摘要】：目的探究在超高场磁共振引导下的高强度聚焦超声手术中射频电磁场B1场匀场技术及人体组织比吸收率(SAR)安全性。方法建立包含温度梯度的女性盆腔模型,分别仿真计算在正常模型匀场系数激励以及在温度梯度模型的匀场系数激励下的射频电磁场B1场的均匀性和局部比吸收率。结果对包含温度梯度的女性盆腔模型采用正常模型的匀场系数激励,组织局部SAR最大值达到10.24 W/kg,超出了国际电工委员会(IEC)对局部SAR值规定的10 W/kg的安全阈值;对包含温度梯度的女性盆腔模型采用温度梯度模型的匀场系数激励,组织局部SAR最大值为9.65W/kg在IEC的安全阈值内。结论在进行超高场磁共振引导下的高强度聚焦超声手术时,需要考虑超声能量在人体形成的温度分布,在温度梯度的基础上重新进行匀场优化能将组织局部SAR值降低到安全阈值内。
[Abstract]:Objective to investigate the technique of radiofrequency electromagnetic field B1 field uniformity and the safety of tissue specific absorptivity (SAR) in high-intensity focused ultrasound (HIFU) guided by ultra-high field magnetic resonance. Methods A female pelvic model containing temperature gradient was established. The uniformity and local specific absorptivity of the radio frequency electromagnetic field B1 under the excitation of the uniform field coefficient of the normal model and the uniform field coefficient of the temperature gradient model were calculated respectively. Results the female pelvic model with temperature gradient was obtained. The uniform field coefficient excitation of the normal model is adopted. The maximum value of tissue local SAR is 10.24 W / kg, which exceeds the safety threshold of 10 W / kg set by IEC for the local SAR value, and the uniform field coefficient of the temperature gradient model is applied to the female pelvic model with temperature gradient. The maximum value of tissue local SAR is 9.65 W / kg within the safety threshold of IEC. Conclusion the temperature distribution of ultrasonic energy in human body should be considered when performing high-intensity focused ultrasound surgery under ultra-high magnetic resonance guidance. Based on the temperature gradient, the local SAR value of the tissue can be reduced to a safe threshold.
【作者单位】：南方医科大学生物医学工程学院;
【基金】：国家自然科学基金(61172034) 广州市科技计划项目(2014J4100160)~~
【分类号】：R310

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