Simulation study on characteristics of low frequency vibration acoustic signal in biological tissue
Vibroacoustic imaging is a new ultrasonic imaging method,which indirectly obtains the acoustic and mechanical information of biological tissue for imaging,and makes up for the lack of resolution of tradi-tional ultrasonic medical imaging,and has potential clinical application value.However,at present,the tissue contrast of vibrational acoustic imaging is not high,one of the important reasons is that the characteristics of low-frequency vibrational acoustic signals in different biological tissues need to be further clarified.Therefore,it is of great value to explore the sensitivity and difference of different tissues to low-frequency acoustic vibration.In this paper,based on k-Wave acoustic simulation platform,the acoustic propagation simulation model of sector array dual-frequency focused ultrasound is constructed,and the intensity of acoustic radiation in confocal region and the amplitude characteristics of low-frequency vibration acoustic signal are calculated and analyzed.In addition,the effects of the characteristics of biological tissue,the angle size,center frequency and the number of lobes on the amplitude of the low-frequency acoustic signal were investigated.The simulation results show that the amplitude of low-frequency vibration signals in different biological tissues is different,which is closely related to the tissue parameters.The dynamic acoustic radiation force in the confocal region can be increased by using a large angle focusing ultrasonic transducer,thus increasing the ultrasound-stimulated acoustic emission(USAE)signal intensity.In addition,the selection of the center frequency of the transducer will affect the intensity of USAE signal.The amplitude of USAE signal does not change obviously when the number N of the transducer is changed.This study provides theoretical support for clarifying the physical mechanism of vibration acoustic imaging in different biological tissues.
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