多线圈阵列磁刺激系统设计及分析

发布时间：2018-03-15 19:39

本文选题：多线圈阵列　切入点：弱磁刺激　出处：《天津大学》2014年硕士论文　论文类型：学位论文

【摘要】：无创式脑刺激技术被广泛应用在脑功能的研究中，并成为治疗神经精神疾病的有效方法之一。精神疾病的早期诊断是治疗的关键所在，但目前缺少早期诊断的客观量化参数。因此本文提出一种可控磁刺激与脑功能成像相结合的思想，以期获得量化脑功能参数。基于系统辨识的思想，本文首次提出弱磁场、可变刺激区域、可调参数的多线圈阵列磁刺激结合的脑功能探测分析平台。平台以磁刺激作为输入，作为输出，构成一个大脑功能的探测系统。本文给出了磁刺激系统的总体构架，包括上位机、控制电路及刺激主电路等环节。基于电磁刺激可以影响大脑神经电活动的机理，本文使用软件，详细分析多线圈阵列磁刺激在头部的感应电磁场分布。从刺激电流幅值、刺激电流变化时间、刺激电流方向、激活线圈的不同组合形式等四个方面进行了详细的电磁仿真并对结果进行分析。通过分析证明多线圈阵列能实现单圆型线圈、八字线圈、线圈阵列等多种刺激形式。刺激区域可以达到整个大脑或特定区域，满足多种探测脑功能要求。根据探测系统刺激的要求，本文设计了多线圈阵列的控制系统，实现刺激电流可变，刺激磁场可调及刺激线圈可控等功能。对于刺激电流输出部分，设计了基于可控开关的全桥电路，，可以生成单向、双向、簇脉冲形式的刺激电流波形。为了实现刺激磁场可调，本文采用带电压环补偿的升降压斩波电路，能够根据磁场强度自动调节输出电压，产生不同强度的刺激电磁场。最后针对刺激线圈可控，提出了基于双向可控硅和光电耦合器的控制方案。对于以上设计方案，给出了电路仿真结果。本文设计的多线圈阵列磁刺激系统，为探测大脑功能和精神疾病的早期诊断提供了一种新的刺激方案。
[Abstract]:Non-invasive brain stimulation technology has been widely used in the study of brain function and has become one of the effective methods for the treatment of neuropsychiatric diseases. The early diagnosis of mental disorders is the key to the treatment. However, there is a lack of objective quantitative parameters for early diagnosis, so this paper presents an idea of combining controllable magnetic stimulation with brain functional imaging in order to obtain quantized brain function parameters. Based on the idea of system identification, this paper for the first time proposes a brain function detection and analysis platform based on weak magnetic field, variable stimulus region, adjustable parameters and multi-coil array magnetic stimulation. The platform uses magnetic stimulation as input and output. This paper presents the general framework of magnetic stimulation system, including upper computer, control circuit and stimulus main circuit. Based on the mechanism that electromagnetic stimulation can affect the electrical activity of brain, the distribution of inductive electromagnetic field of multi-coil array magnetic stimulation in the head is analyzed in detail by using software. The amplitude of stimulation current, the change time of stimulation current, the direction of stimulation current, the distribution of inductive electromagnetic field of multi-coil array magnetic stimulation are analyzed in detail. Four aspects such as different combinations of active coils are carried out in detail and the results are analyzed. It is proved that the multi-coil array can realize single circular coils, eight-character coils, and so on. Coil array and other stimuli. The stimuli can reach the whole brain or a specific region, and meet the requirements of a variety of brain function detection. According to the requirement of detecting system stimulation, the control system of multi-coil array is designed in this paper, which realizes the functions of variable stimulus current, adjustable magnetic field and controllable stimulation coil. A full bridge circuit based on controllable switch is designed, which can generate the stimulus current waveform in the form of unidirectional, bidirectional and cluster pulses. In order to realize the adjustable magnetic field of the stimulus, this paper uses a voltage loop compensated voltage chopper circuit. The output voltage can be automatically adjusted according to the intensity of the magnetic field, and the exciting electromagnetic field with different intensity can be generated. Finally, a control scheme based on bidirectional thyristor and optocoupler is proposed to control the stimulation coil. The simulation results are given. The multicoil array magnetic stimulation system designed in this paper provides a new stimulus scheme for the early diagnosis of brain function and mental illness.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP391.9;R749

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