Study On The Technique And System Of Medical Ultrasonic Seepage And Shock

Ultrasound has the characteristics of cavitation,mechanical and thermal effects,and it has a very broad application prospect in medical diagnosis and treatment.Ultrasound were widely studied in enhancing drug percutaneous permeability,but further studies are necessary on the parameters optimization,safety and mechanism of sonophoresis.Using dual frequency ultrasound was an effective way to enhance drug permeation efficiency and reduce the risk of heat damage.However,the experimental device,parameter optimization,enhancing effect of drug permeation and mechanism of dual frequency sonophoresis need to be further studied.Ultrasonic shock wave therapy is a new treatment for severe coronary heart disease.The intensity and range of sound pressure at the focus are the key indicators which determine the effect and safety of the treatment.At present,there are few researches on the theory of cylindrical ultrasonic shock wave.Further study is needed on the acoustic field characteristics of parabolic surface of transducer.Dose and mechanism of ultrasonic shock wave in the process of angiogenesis should be further clarified.In this study,the application of ultrasonic seepage and shock wave technology was studied in sonophoresis and myocardial ischemia treatment.The mechanism of ultrasonic cavitation and shock,the device of sonophoresis and myocardial ischemia treatment were studied.The application of ultrasonic physical mechanism and information,electronics and biotechnology in the field of biomedicine were explored.Main contents of this research are as follows:(1)Sonophoresis by single frequency ultrasonicIn the process of single frequency sonophoresis,the main factors that affect drug permeation are physical and chemical parameters,ultrasonic parameters and medium parameters.Firstly,the influence of physical and chemical parameters on permeation coefficient was explored by using extreme learning machine(ELM).Secondly,the influence of ultrasonic parameters on cavitation effect were studied through simulation and aluminum foil experiment.Then the experiment of medium thermal conductivity and interface temperature was designed to investigate the influence of thermal properties of medium on sonophoresis.Finally,the sonophoresis experiment of diclofenac sodium was designed to study the influence of ultrasonic parameters on drug permeation.Ultrasonic cavitation effect may be the mechanism of drug sonophoresis.(2)Percutaneous permeability of sinomenine hydrochloride(SIN)using dual frequency sonophoresisFirstly,the physical mechanism for dual frequency ultrasonic enhanceing cavitation was simulated.Secondly,a double frequency ultrasonic device with 45°oblique angle on both sides was designed to enhance SIN permeation.The influence of duty ratio,intensity and action time of double frequency ultrasonic on SIN sonophoresis was studied.The advantages of dual frequency ultrasonic to single frequency ultrasonic on sonophoresis were studied.The sonophoresis mechanism of 45°oblique angle dual frequency ultrasound was investigated.The results showed that ultrasonic pulse and continuous mode had the same effect on SIN sonophoresis.Dual frequency ultrasound could downregulate the threshold of intensity and action time of SIN sonophoresis,and reduce risk of skin damage as well.Dual frequency ultrasound had advantages in enhancing the sonophoresis efficiency of SIN compared with single frequency ultrasonic.The mechanism of of dual frequency sonophoresis was a synergistic effect rather than a cumulative effect.(3)Cylindrical electromagnetic ultrasonic shock wave systemThe sound field of cylindrical electromagnetic ultrasonic shock wave transducer was explored.The sound field reflected by parabolic rotating concave surface was equivalent to the ring concave spherical shell vibration field.The influence of pulse characteristics,acoustic nonlinearity,propagation attenuation and interface reflection on acoustic field were discussed.A modified ultrasonic shock wave field formula was proposed.The ultrasonic shock wave system was set up and the width of discharge pulse and the charging value of high voltage capacitor were tested.The test results meet the design requirements.According to the actual parameters of the transducer,simulation software was used to simulate the intensity and range of the sound field at the focus.It was showed that the relative sound pressure(P/P0)at the focus of the treatment target area was about 630.The focus area of the sound field was shaped like a date nucleus,with a long axis of 13 mm and a short axis of 1.9 mm.The treatment depth was about 15 cm.(4)The ultrasonic wave promoted expression of vascular endothelial cell growth factorThe relationship between the expression of endothelial nitric oxide synthase(eNOS),vascular endothelial growth factor(VEGF)in human umbilical vein endothelial cells(HUVECs)and the ultrasonic wave energy density,impact times and total energy was studied.The physical mechanism was analyzed from the aspects of shear stress and cavitation effect.It was showed that when the energy density of shock waves was low(0.04,0.09,0.12 mJ/mm2),ultrasonic shock waves could promote the expression of VEGF and eNOS.When the energy density reached 0.16 mJ/mm2,the expression was not promoted.The optimal combination of shock wave parameters to promote VEGF and eNOS were 0.09 mJ/mm2 with 250 shocks and 0.09 mJ/mm2 with 350 shocks respectively.It was found that the expression of eNOS increased with the increase of total energy,which reached the maximum when the total energy reached 31.5 mJ/mm2,and then decreased.