高能超声聚焦肿瘤治疗系统——图像处理子系统

【作者】 杨兵；

【导师】 谢寄石； 黄大贵；

【作者基本信息】 电子科技大学 ， 机械电子工程， 2003， 硕士

【摘要】 恶性肿瘤疾病是威胁人类健康的最严重的疾病之一，如何治疗恶性肿瘤一直是努力的方向。当今使用的方法主要有手术、放疗和化疗等，手术的方法容易造成癌细胞转移，并且人体的有些部位不能进行手术，也会给病人生理带来痛苦；放疗采用放射线治疗肿瘤，在杀死癌细胞的同时，也会杀死正常组织细胞；化疗采用化学药物治疗肿瘤，也会给人体正常细胞带来损伤。将超声波用于肿瘤治疗是近年来各国研究的热点，通过将超声波聚焦到肿瘤组织上，利用其热效应杀死肿瘤细胞，不会给患者带来生理痛苦，也不会像放疗和化疗那样产生严重的副作用，因此是一种很有发展前途的新方法。开展高能超声聚焦肿瘤治疗系统的研制具有巨大的实用价值和经济效益。B超图像处理子系统是高能超声聚焦肿瘤治疗系统的关键子系统之一，对它的研究直接关系到肿瘤治疗系统的成败。医学三维图像能提供较二维图像更为丰富的信息，为医生诊断和肿瘤治疗提供准确的数据，本文的目的就是对肿瘤组织进行三维重构，生成肿瘤的三维数据供分析、治疗使用。本文对超声波原理、B超成像原理、图像采集技术、数字图像处理技术、三维可视化技术等进行了较为全面的研究，确定了图像处理的总体方案，首先用Matlab对要采用方法进行仿真以验证可行性，然后进行软件编制和调试。本文图像处理采用的总体方案是：首先，运用图像采集卡从B超仪获取一系列超声断面图像，然后对超声图像进行去噪预处理，再通过人机交互的方式，手工勾画出各层图像中感兴趣目标的轮廓线，并运用三维重构技术进行三维重构，最后运用OpenGL将三维图像显示出来。鉴于超声成像的技术原理，去除图像中的闪斑噪声一直是图像处理的难点所在。本文提出了小波变换和灰度调整相结合的处理方法来去除图像噪声，通过试验获得了较为满意的结果。即去除了闪斑噪声，又提高了图像的清晰度。由二维轮廓线实现三维重构是一个极为复杂的问题，本文对用于单轮廓线重构的最短对角线法算法进行了研究，并提出了改进措施，实现了单轮廓线之间的连接。本文将OpenGL运用于三维图像的显示，提高了图像的显示效果，可以方便地实现图像的缩放、平移、旋转等功能。更多还原

【Abstract】 Malignant tumor is one of the most serious illness threatening to people health, how to cure it is always the goal that people make great efforts to. Today, the main methods used in curing tumor are surgery, actinotheraphy, chemotherapy and so on. Surgery is easy in casing malignant cells transfer, and it is impossible to operate in some place of the body, it can also bring great harm to person’s body. Actinotheraphy use radiation to treat tumor, at the same time of killing malignant cells, it will also kill the general cells. Chemotherapy use chemical drugs to treat tumor, it also bring harm to person’s body. It is a new hotspot that using ultrasonic to treat tumor in the world recently. Focusing ultrasonic on tumor, we can kill the malignant cells using the heat generated by ultrasonic without serious side effect like actinotheraphy or chemotherapy, so, it is new method with great hope. That we make the research of the system of HIFU (high-intensity focused ultrasound) have great practicability and economic benefit.Ultrasound B-scan images processing subsystem is one of the key subsystem of the tumor therapy system with HIFU, playing an important role in the development of the tumor therapy system with HIFU. Medicine 3D-image can give more information than 2D-image, and provide exact data for diagnosis and treatment. The aim of this paper is to reconstruct 3D-image of tumor, and offer 3D-data used by analysis and therapy.In this paper, we study this aspects of Ultrasonics, B-scan imaging, image collecting, Digital Image Processing, and establish the whole frame of image processing. We first use MATLAB to simulate for its feasibility, then write programme and debug it. The whole frame used in this paper is that, First, by using video card, we get a series of B-scan images, then delete the noise in this images. Secondly, draw the outline of interesting object in each image by manual, through clicking mouse on screen. Thirdly, reconstruct 3D-image using 2D contour. Finally, using OpenGL lib, we show the 3D-image on screen.Because of the principle of ultrasonic imaging, removing the speckle noise in the images is the most difficult focus in ultrasonic image processing. In this paper, we present wavelet shrinkage and gray level mapping techniques to remove noise, and get satisfying result by experiment. The method not only removes the speckle noise, but also enhances contrast.<WP=5>Reconstructing 3D-image from 2D contour lines is a very difficult problem, we study the shortest diagonal algorithm that is used for signal contour line, and present enhanced algorithm, by that, we realize the connection between two contour lines.In this paper, we use OpenGL technique in showing 3D-image, improving display effect. It is very easy to realize image scale, image translation, image rotation, and so on.更多还原