EFFECT OF CALCIUM-CHLORIDE ON SODIUM ALGINATE MICROBUBBLES AS ULTRASOUND CONTRAST AGENT

In order to stabilize microbubbles without coating layers to be used a s ultrasound contrast agent, the viscosity of the liquid for storage h as to be increased. Sodium alginate is a material which forms viscous liquid when its powder is dissolved in water. The viscosity may vary f rom 1 cP to about 100 cP when the amount of material used is increased from 0.1% to 1%. However, the viscosity is still not enough to make s table microbubbles which can be stored for over several weeks. In this paper, by adding calcium chloride to the sodium alginate solution, a gel-type solution is produced which has a high viscosity capable of ho lding microbubbles for a long time. By measuring the viscosity of the sodium alginate solution and the solution with calcium chloride soluti on added, it is known that the solution is changed from a Newtonian li quid to a non-Newtonian liquid when calcium chloride solution is added . Since the attenuation coefficient of microbubble dispersion is propo rtional to title number of microbubbles, the disappearance of microbub bles lowers the attenuation coefficient. Therefore, in this study the attenuation coefficient is used as an estimating parameter for the lif etime of microbubbles.