经颅磁刺激电磁场分析及线圈设计的研究

发布时间：2018-12-11 21:41

【摘要】： 经颅磁刺激技术通过将磁场施加于人脑来影响大脑的机能,从而达到诊断或治疗的目的。随着经颅磁刺激技术在各个领域内的广泛应用,研究经颅磁刺激中电磁场便显得尤为必要。针对经颅磁刺激特点,本文主要在经颅磁刺激电磁场环境仿真,线圈不同绕法和参数分析,线圈组电磁场研究三个方面进行了深入研究。首先是模拟电磁场环境。这涉及到3个主要部分的建模问题:人的头部,线圈,电路。利用真人头部核磁共振图像作为原始数据,按照灰度阈值将不同人体组织轮廓提取出来构成真实头模型,再经过后期平滑处理和有限元网格剖分将其转化为头部有限元模型。提出一种螺旋线式建模方法对各种不同绕法线圈进行有限元建模。磁刺激仪电路也被转化为有限元模型,与由头部有限元模型和线圈有限元模型组成的电磁场一起进行电路电磁场耦合分析。其次通过详细分析蚊香型,螺旋线型,混合式线圈,八字形线圈的电磁场表现,总结出它们的相同点和不同点,并得出混合式线圈性能最优且能替代八字形线圈的结论。然后对混合式线圈的各个参数在电磁场的作用进行总结,并以此为理论基础设计出经颅磁刺激电磁场分析系统,实现对经颅磁刺激电磁场的自动分析,并根据使用者的需求自动提供可用于实际制作的线圈参数。最后通过分析线圈组的电磁场,发现线圈组在控制磁刺激范围,提高磁刺激深度方面要优于单线圈系统。119导脑部磁刺激仪的设计便充分利用了线圈组的优势。将119个小线圈按照刺激部位密布于头部周围,通过控制需要的线圈组工作,从而实现不同的功能。线圈磁场检验试验表明:实际测量值与仿真分析值基本吻合,系统提供的线圈参数可靠,能够满足临床线圈设计的需要。
[Abstract]:Transcranial magnetic stimulation affects the function of the brain by applying magnetic field to the human brain, thus achieving the purpose of diagnosis or treatment. With the wide application of transcranial magnetic stimulation in various fields, it is necessary to study electromagnetic field in transcranial magnetic stimulation. In view of the characteristics of transcranial magnetic stimulation (TMS), this paper mainly focuses on three aspects: environment simulation of transcranial magnetic stimulation (TMS), coil winding method and parameter analysis, and electromagnetic field research of coil group. The first is to simulate the electromagnetic environment. This involves the modeling of three main parts: the human head, the coil, and the circuit. Using the real head MRI image as the original data, different human tissue contours are extracted according to the gray threshold to form the real head model, which is transformed into the head finite element model after the later smoothing processing and the finite element meshing. A helical modeling method is proposed for finite element modeling of various winding coils. The circuit of the magnetic stimulator is also transformed into a finite element model, which is coupled with the electromagnetic field which is composed of the head finite element model and the coil finite element model. Secondly, the electromagnetic field of mosquito coil, helical coil, hybrid coil and octagonal coil are analyzed in detail, and their similarities and differences are summarized, and the conclusion that the hybrid coil has the best performance and can replace the octahedral coil is obtained. Then the function of the parameters of the hybrid coil in the electromagnetic field is summarized and a transcranial magnetic stimulation electromagnetic field analysis system is designed based on this theory to realize the automatic analysis of the transcranial magnetic stimulation electromagnetic field. The coil parameters that can be used in actual production are automatically provided according to the user's needs. Finally, by analyzing the electromagnetic field of the coil group, it is found that the coil group is superior to the single coil system in controlling the magnetic stimulation range and increasing the magnetic stimulation depth. The design of 119 magnetic stimulator in the brain makes full use of the advantages of the coil group. 119 small coils were distributed around the head according to the stimulation position, and different functions were realized by controlling the needed coil groups. The results of coil magnetic field test show that the measured values are in good agreement with the simulation results, and the coil parameters provided by the system are reliable and can meet the needs of clinical coil design.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2009
【分类号】：R312

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