The physical parameters of acoustic absorber play an important role in estimating acoustic intensity in high intensity focused ultrasound(HIFU)using infrared thermometry.In order to analyze the rule of the influence o...The physical parameters of acoustic absorber play an important role in estimating acoustic intensity in high intensity focused ultrasound(HIFU)using infrared thermometry.In order to analyze the rule of the influence of different physical parameters(density,sound speed,attenuation,thermal diffusivity,specific heat capacity)on the measurement results,the theoretical simulation was applied.The sound and thermal field in the absorber with different physical parameters and same power output are calculated based on layered model.The finite difference method is used to calculate the temperature change at interface during the irradiation.The character value of sound field in the focal region,e.g.intensity on axis and—6 dB beam width,are calculated by the method based on hydrophone and infrared thermal imaging.The result is compared with the theoretical characteristics of sound field in water.The influence of different physical parameters on the result is analyzed.The acoustic and thermal parameters of absorbers have no significant influence on the measurement results except the sound speed,and the maximum relative difference is<15%.Due to the changing of sound speed in the absorber,the distribution of thermal field in absorber is changed,which leads to a great deviation,and the maximum relative difference in-6 dB beam width and axis intensity are 95.37%and 69.97%,respectively.Therefore,the appropriate choosing of this parameter plays an important role.When the acoustic parameters of absorber are similar to that of water,the measurement results based on hydrophone and infrared thermal imaging have satisfactory accuracy within the focal region.展开更多
基金supported by the 2017 Ministry of Science and Technology Key Research and Development Program(2017YFC0108900)the National Natural Science Foundation of China(11774231)+3 种基金the Jiangxi Natural Science Foundation(20151BAB202014)the National Major Scientific Research Instrument Development Project(81727806)2017 Shanghai Science and Technology Support Program(17441906400)the 2015 Shanghai Science and Technology Support Program(15441900700)。
文摘The physical parameters of acoustic absorber play an important role in estimating acoustic intensity in high intensity focused ultrasound(HIFU)using infrared thermometry.In order to analyze the rule of the influence of different physical parameters(density,sound speed,attenuation,thermal diffusivity,specific heat capacity)on the measurement results,the theoretical simulation was applied.The sound and thermal field in the absorber with different physical parameters and same power output are calculated based on layered model.The finite difference method is used to calculate the temperature change at interface during the irradiation.The character value of sound field in the focal region,e.g.intensity on axis and—6 dB beam width,are calculated by the method based on hydrophone and infrared thermal imaging.The result is compared with the theoretical characteristics of sound field in water.The influence of different physical parameters on the result is analyzed.The acoustic and thermal parameters of absorbers have no significant influence on the measurement results except the sound speed,and the maximum relative difference is<15%.Due to the changing of sound speed in the absorber,the distribution of thermal field in absorber is changed,which leads to a great deviation,and the maximum relative difference in-6 dB beam width and axis intensity are 95.37%and 69.97%,respectively.Therefore,the appropriate choosing of this parameter plays an important role.When the acoustic parameters of absorber are similar to that of water,the measurement results based on hydrophone and infrared thermal imaging have satisfactory accuracy within the focal region.
