Research On Measurement Of Ultrasonic Field Distribution Based On Hydrophone

With the constant development of medical ultrasound, the ultrasounddiagnosis in our country has made great progress and become one of the mostcommon means of medical diagnosis. In recent years, ultrasonic medical device tradein China has developed rapidly. The ultrasound diagnostic equipments of differentuses often come forth. In order to protect the safety of the lives of patients, theultrasonic diagnostic equipment in use must be effective and safe. As early as in theyear1997, our country released GB/T16846-1997Requirement for the declarationof the acoustic output of medical diagnostic ultrasonic equipment", equating withIEC61157:1992, and continued to amend the standard, released GB/T16846-2008in2008. The standard stipulates the manufacturer of ultrasonic medical diagnosticequipment to publish the maximum output level of acoustic output in single orcomplex mode and compulsories the ultrasonic diagnostic equipment manufacturerswhose output level of acoustic output is higher than that in the standard, to releasethe sound output level to the public so as to ensure the safety of human life. Underthis background, this paper introduces the sound field measurement of medicalultrasonic diagnostic equipment in detail.This project starts from the question how to measure ultrasonic field. After doing alot of work to review the relevant literatures about standards and applications onhydrophone methods to measure the ultrasonic field, based on the hardwareenvironment of medical equipment inspection center of Shenzhen Academy ofMetrology and Quality, we realized the goal of hydrophone method to measureultrasonic field by the construction of hardware system and preparation of software.The main research work is as follows:Firstly, focus on the hydrophone method to measure ultrasonic field and illustrate theapplication of the principle of hydrophones in the measurement of ultrasonic field.Set up the ultrasonic field and then check out the factors that affect the accuracy ofthe sound field measurement.Secondly, give the description of the hardware components of ultrasonic fieldmeasurement system based on hydrophone and illustrate the qualification andprinciple of every part. The software system has been designed with the idea of modularization, so that key algorithms and the bottom part of motor motion controlsystem are completed by an independent module. The software met the requirementsof the standard acoustic output by referring to the IEC announced formula andmethod of date processing. The modular design allows the observer intuitive to seeall the time in the sound field measurement and every step of the measurement datacan be easily saved for later queries.Finally, much preliminary testing of the system was done. Test results show that thecharacteristics of the signals connected by the measurement system is in line withthat in the past literature summary. Repeatability is fine. Meet the requirement of thenational standard to measure the ultrasonic field distribution parameters withhydrophone. The paper tried to analysis all aspects about system accuracy so as tominimize the error to minimum. At last, the uncertainty of the system was analyzedand the conclusions were given.