Design And Implementation Of Probe-guided Phased Array Ultrasound Focusing HIFU Prototype

High Intensity Ultrasound Focusing(HIFU)is a modern cancer treatment technology.By irradiating the soft tissue of the lesion area in vivo with high-energy ultrasound,the tumor cells in the soft tissue are killed after thermal coagulation and solidification,thus treating cancer.Compared with the traditional cancer treatment technology,HIFU treatment technology has a series of advantages,such as non-invasive,non-chemical damage,no side effects,high safety,and has become a research hotspot at home and abroad.However,due to the inhomogeneity of tissue media in human body,the velocity and impedance of ultrasound in different parts of the body are not consistent,which ultimately leads to the focus of ultrasound in human body.In order to solve the problem of ultrasound focusing in human body,a probe-guided phased array ultrasound focusing scheme is proposed,and a prototype verification system is designed to solve the difficulty of focusing in human body with traditional treatment technology.The specific research contents and innovations of the article are as follows:1.A probe-guided ultrasonic focusing scheme is proposed.The basic principle is to set a probe with feedback at the pre-focusing position.The system uses the ultrasonic signal feedback from the probe to adjust the transmission delay so that all the routes of ultrasound can reach the focusing position at the same time to achieve focusing.Compared with the traditional focusing technology,the biggest advantage of this scheme is that it only needs to change the position of the probe and then adjust the system parameters to achieve ultrasound focusing at any position in a limited area,without changing the physical position and structure of the whole launcher.In addition,the probe feedback can eliminate the requirement of ultrasound propagation on the media environment,and improve the poor focusing effect of traditional focusing methods due to the different media environment in human body.2.A probe-guided phased array ultrasound focusing model is established,and its theoretical calculation and simulation are completed.The acoustic field distribution at the focusing surface is modeled by MATLAB software,and the long axis radius and the short axis radius of the focusing spot are calculated to be 4 mm and 0.8 mm respectively.The MATLAB simulation results of the probe-guided phased array ultrasound focusing agree well with the theoretical design,thus verifying the correctness and feasibility of the probe-guided ultrasound focusing scheme.3.The prototype of the proposed focusing scheme is designed and the focusing effect test is completed.The prototype is mainly composed of phased array ultrasonic transmitter and probe receiver.The acoustic signal of ultrasonic emission is received by probe.The ultrasonic signal feedback from probe adjusts the transmission delay so that all routes of ultrasound simultaneously reach the focusing position to achieve focusing,and then adjusts the movement of probe near the focus.Measure the focal area size.The results show that the probe can guide the focusing,and the radius of the long axis and the short axis is 4 mm and 0.9 mm,which can meet the clinical treatment needs.In this experiment,the probe-guided phased array ultrasound has achieved focusing,and the effect is obvious;the sound pressure is approximately axisymmetric distribution,the long axis radius of the focusing area is 4 mm,the short axis radius is 0.9 mm,which is consistent with the simulation results of MATLAB.This verifies the correctness of the design and implementation of the probe-guided phased array HIFU prototype,and the size of the focusing region measured meets the requirements of clinical treatment.In the future,in the process of HIFU treatment with this focusing scheme,the HIFU machine will be able to focus on human tumors without moving and directly inserting probes into the tumors.