Research On The Detection System Design Of Extracorporeal Shock Wave Lithotripsy

Calculus is a common clinical medicine disease which mainly occurs in the human kidneys, bladder, gallbladder and other internal organs. So, diagnostic and therapeutic means of specific are needed. At present the common method is to scan calculus through the B ultrasound guided ultrasonic lithotripsy machine to aim and crush stones. The treatment module and the ultrasonic scan module are to make integration, due to the ultrasonic scanning with MIMO sweep mode. In the circumstances of the diversity and complexity that the human tissue has, two modules need to be calibrated and a lot of work has to be done before the treatment. Moreover, the operator’s skill and experience are greatly demanded.Chapter two introduces the properties of medical ultrasound and common ultrasonic detection method. Chapter three introduces a three dimensional human tissue ultrasound simulation models based on the layered characteristics of human body tissues. The model is tested to be proved correct. Chapter four introduces the ‘single launch multiple receive’ detecting method, including the short-pulse chirp and correlation delay detection method. The method is tested in the three dimensional body model. Chapter five introduces the hardware of the system. The system is tested under laboratory environment in a water tank. The outcome proves that the method is feasible. The innovation points and the work of this paper involve:1. A three-dimensional simulation model is built based on the hierarchical nature of human tissue and the structral characteristic of human tissue. The velocity of sound in human tissue, sound attenuation, the impact of non-linear characteristics and density of human tissue are combined to the ultrasonic sound waves field function. The K-wave method is used to built a three dimensional time domain human tissue model.2. Detection module and Crushed Stone module are difficult to achieve integration which leads to the high demand of the skill and experiences of the operator. A ‘single launch multiple receive’ detection method based on the thought of Bionic Design is introduced. Short pulse of chirp is used to detect the location of the stone combining the characteristics of the human channel. The method decreases the reliability of experience and skill of the operator and the cost of the hardware system.3.The hardware system is built based on the method we designed. The method is tested in a tank under laboratory environment for human body are similar to the water. The experiment shows that the detection method is able to guide the probe to aim at the stone accurately which prove the detection method is capable in reality.