【作者】 李丽丽；

【导师】 田学隆；

【作者基本信息】 重庆大学 ， 生物医学工程， 2011， 硕士

【摘要】 神经肌肉疾病已经成为严重威胁人类健康和生命的重大疾病之一,且无根治的办法,所以,及时地发现和诊断对于该疾病的预防、治疗、药物研究和挽救患者的生命具有重大的临床意义。目前,对神经肌肉疾病的诊断评估方法有多种,但是在使用的过程中,存在一定的限制因素。而局部生物阻抗分析为神经肌肉疾病的评估提供了一种新的、非损伤性的手段。研究证明,神经肌肉疾病患者肌纤维的结构和生理特性较正常人已经发生了变化,而局部生物阻抗参数与这种变化之间存在确定的联系。文中根据国内外的研究现状和实际的功能需求设计了用于神经肌肉疾病评估的局部生物阻抗分析测量系统。系统采用使用广泛且功能强大的PIC单片机作为主控芯片,通过控制直接数字频率合成器DDS产生频率从2K到300KHz自动变化的跳频正弦信号,作为测量系统的激励源,然后根据局部生物阻抗分析原理测量出包含局部阻抗信息的电压信号,从而获得局部阻抗的幅值和相位。测量系统能直接用于局部阻抗的测量,克服了现有测量设备的不足,又符合向便携化方向发展的趋势,具有重要的实用价值。根据局部生物阻抗分析用于神经肌肉疾病评估的功能需求,文中采用PIC18F4585单片机和C语言作为系统的控制单元模块,其他功能模块包括正弦信号发生模块、压控恒流源模块、电极系统、前置放大电路、幅相测量模块、A/D转换模块和串行通信模块等。详细介绍了个单元电路模块的设计原理和设计过程以及驱动程序结构流程。通过对系统整体电路的调试和实验测量,应用结果表明,系统的性能较好,在测得的人体局部生物阻抗正常范围内,频率平均幅值相对误差在2%以内,频率平均相位绝对误差基本在1°以下。更多还原

【Abstract】 Neuromuscular disease has become one of harming human health and life’s significant disease and there is no radical treatment for it at present. So, prompt detection and diagnosis has great meaning in prevention, therapy, drugs research and rescuing patients’life. For now, a variety of treatments for neuromuscular disease diagnosis assessment, but they may have certain limiting factors in the process of operation. However, Local Bioimpedance Analysis (LBA) provides a completely new, invulnerable method for the evaluation of neuromuscular disease.Studies have shown that neuromuscular disease patients’structure of muscle fibers and physiological properties have changes comparing with normal group, and localized bioimpedance parameters have definitive link with these kinds of changes. The paper introduces measurement system of LBA for evaluation of neuromuscular disease depending research situation at home and abroad and actual functional demand. The system uses powerful and generally applicable PIC microcontroller to main control chip, through control direct digital frequency synthesizer DDS to create automatic changing sine signals at frequencies from 2K to 300 KHz as excitation sources, and then, measuring voltage signal which involves local impedance data on the basis of LBA, to finally obtain the amplitude and phase of localized impedance. The measurement system can be used in the measuring localized impedance directly, which effectively overcomes existing equipments disadvantage and meet the portable tide. It has a significant and practical worth.Depending on the functional requirements of neuromuscular disease assessment based on LBA, this paper takes PIC18F4585 Microcontroller and C Language as the system control units, with other functions including Sine Signal Producing Module, VCCS, electrode system, preamplifier, phase measurement, A/D converter and serial communications. This paper introduces in detail the design principle, process of single circuit and the driver structure processes. The applied results show that the system is of good performance by debugging the whole circuit and experimental tests. Within the normal range of the human localized bioimpedance level, relative errors of average amplitude of frequencies by the present method are less 2% and absolute errors of average phase roughly holds 1%.更多还原