治疗超声的电子聚焦系统

发布时间：2018-01-15 23:15

本文关键词：治疗超声的电子聚焦系统　出处：《深圳大学》2016年硕士论文　论文类型：学位论文

【摘要】：近年,治疗肿瘤的基本动向从传统的放疗和手术切除向尽量保护功能的微创或者无创手术的转变。高强度聚焦超声具有无创和价格低廉等特点,是一种新型的肿瘤治疗方式,因此开发出高性能的超声治疗系统对治疗肿瘤具有重要的意义。高强度聚焦超声(High-Intensity Focused Ultrasound,HIFU)利用压电换能器产生超声波,并聚集于一个很小的焦域,在体外就能对肿瘤细胞进行聚焦加热,同时利用超声波机械效应、热效应、空化效应等对肿瘤组织细胞的作用,最后使其失活,达到肿瘤消融的效果。临床上,超声治疗已经得到不同的应用,比如:子宫肌瘤、肝癌、乳腺癌、恶性骨肿瘤、软组织肉瘤等。传统超声治疗主要采用是固定的焦点,使用电机带动实现区域治疗,这种方式使得治疗时间变长,不能达到最佳的治疗效果。但是按照传统电子聚焦阵列设计方案,要达到较好的聚焦和指向性能,治疗探头需要约1000(32X32)或以上的通道数,令到系统成本成为发展治疗阵列系统的瓶颈。本论文主要是开发一款以兼顾成本和性能为原则的超声治疗阵列系统。具体实现了128通道快速电子聚焦和多点聚焦的方式。该系统由探头、发射系统和控制软件部分构成。硬件部分主要包括:探头发射激励部分,发射控制部分以及背板连接部分。其中主要设计到有探头激励信号产生模块、激励信号参数控制模块、SDRAM数据缓存模块、USB2.0数据传输模块、高压与温度监控模块以及相应的电源转换模块。上位机软件部分调用发射波形文件来改变激励频率、脉冲个数,同时可支持调节脉冲重复频率和发射重复次数以及聚焦点来控制声辐射力的大小。软件界面中实时的显示发射板温度以及激励高压来监控整个激励过程,通过USB2.0对信号进行上位机传输。最后对系统进行了相应的测试实验。在发射模块中,测试每一个通道是实际输出波形,并测试了相应的时延。利用OptiSon激光声场对特定参数下声场进行测试,结果显示有一定的聚焦效果。利用RFB2000声辐射力天平对声功率进行测试,得到声功率与脉冲个数、发射电压峰峰值成正比的关系。最后利用水听器测试,得出特定聚焦深度情况下的声压与声强跟深度的关系,同时也通过控制时延让焦点进行偏转。该套治疗超声系统实现了对128通道阵元的激励,实现电子聚焦以及多焦点的聚焦方式,同时支持通道扩展,支持外部触发并且高度集成化。为超声治疗方向研究提供开放式的平台,具有深远的应用前景。
[Abstract]:In recent years, the basic trend of tumor treatment from traditional radiotherapy and surgical resection to minimally invasive or non-invasive surgery as far as possible protection function. High intensity focused ultrasound has the characteristics of non-invasive and low-cost. It is a new type of tumor therapy. Therefore, the development of high performance ultrasound therapy system is of great significance in the treatment of tumor. High intensity focused ultrasound (HIFU) is high intensity Focused Ultrasound. HIFU) uses piezoelectric transducers to produce ultrasonic waves and gather in a small focal region, which can focus on tumor cells in vitro, and at the same time use ultrasonic mechanical effect, thermal effect. The effect of cavitation on tumor tissue cells, finally inactivation, to achieve the effect of tumor ablation. Clinically, ultrasound treatment has been different applications, such as: uterine leiomyoma, liver cancer, breast cancer. Malignant bone tumors, soft tissue sarcoma and so on. Traditional ultrasound treatment is the focus of fixation, the use of motor drive to achieve regional treatment, this way makes the treatment time longer. However, according to the traditional electronic focusing array design, to achieve better focusing and pointing performance, the therapeutic probe needs about 1000V 32x32) or more channels. The system cost has become the bottleneck of the development of therapeutic array system. In this paper, a ultrasonic therapy array system based on both cost and performance is developed. The 128 channel fast electronic focusing and multi-points are realized. The system consists of a probe. The hardware part mainly includes: probe transmitting excitation part, transmitting control part and backplane connecting part. Among them, the module is mainly designed to generate probe excitation signal. Excitation signal parameter control module SDRAM data buffer module USB2.0 data transmission module. The module of high voltage and temperature monitoring and the corresponding power conversion module. The software part of the host computer calls the waveform file to change the excitation frequency and the number of pulses. At the same time, it can control the acoustic radiation force by adjusting the pulse repetition frequency and the number of repeats and focus. The software interface can monitor the whole excitation process by displaying the emitter temperature and exciting high voltage in real time. The signal is transmitted by the upper computer through USB2.0. Finally, the system is tested. In the transmitting module, each channel is the actual output waveform. The corresponding time delay is measured and the acoustic field under certain parameters is measured by using OptiSon laser acoustic field. The results show that it has a certain focusing effect. The acoustic power and the number of pulses are obtained by measuring the sound power by using the RFB2000 acoustic radiation force balance. The peak value of emission voltage is proportional to the peak value. Finally, the relationship between sound pressure and sound intensity and depth is obtained by hydrophone test. At the same time, the focus is deflected by controlling the time delay. The ultrasonic therapy system realizes the excitation of 128 channel elements, electronic focusing and multi-focus focusing, and supports channel expansion. It supports external trigger and is highly integrated. It provides an open platform for ultrasonic therapy research and has a broad application prospect.
【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：R454.3

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