Study On Preparation And Ultrasonic Imaging Performance Of High Acoustic Impedance Material For Catheters

Ultrasound guided catheterization is a rising operation in clinical diagnosis and treatment,especially for emergency treatment.However,the visibility of catheter's ultrasonic image in human body is poor,increasing the difficulty of accurate catheter position.To solve such problem,this study develops a catheter material possessing good ultrasonic visibility by adding inorganic filler with high acoustic impedance into polymer.The effects of inorganic filler type,amount and dispersion condition in polymer on the ultrasonic visibility of the composites were investigated.The mechanical property and biomedical safety of the material for ultrasound visible catheter were then tested for further application.The main research contents include:1.The basic formula of high acoustic impedance catheter material was determined,and the feasibility of the idea(i.e.to enhance ultrasonic visibility of catheter by adding high acoustic impedance inorganic filler into polymer matrix)was verified by experiment.2.Established a quantitative characterization method for catheter ultrasonic visibility measurement by analyzing the grayscale curve of ultrasonic image through Image J software.3.The effects of inorganic filler type and amount on the acoustic performance and the ultrasonic visibility of inorganic/polymer composite were investigated through theoretical prediction and experiments.The results turned out that the difference in acoustic impedance of inorganic powder has little contribution to the increasement of composite acoustic impedance when the acoustic impedance of inorganic powder is 5 times higher than that of polymer matrix.Furthermore,with the increasing amount of inorganic powder,the acoustic impedance of composite increases,and the ultrasonic visibility of composite improves as well.4.The effect of filler particle size on the acoustic impedance and the ultrasonic visibility of composite were studied.The results indicated that composite contains inorganic filler with larger particle size has better ultrasonic visibility.Combined with the characteristics of acoustic scattering,it is recommended that the size of inorganic filler dispersed in polymer should be greater than 1/10 of the wave length.5.The biomedical safety of the material for ultrasound visible catheter was tested.The results exhibited that after 30 minutes' steam sterilization under 121?,the thermodynamic performance and the mechanism property of composite have no obvious change,which means that the material can withstand common sterilizing condition for biomedical material.The HPLC spectrums of material leaching solution gained under different conditions showed no obvious difference,which implies additions in the composite did not migrate out of material.Meanwhile,the result of insoluble particle examine also meets the relevant requirement in Chinese Pharmacopoeia.