In order to stabilize microbubbles without coating layers to be used as ultrasound contrast agent, the viscosity of the liquid for storage has to be increased. Sodium alginate is a material which forms viscous liquid when its powder is dissolved in water. The viscosity may vary from 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 stable 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 holding microbubbles for a long time. By measuring the viscosity of the sodium alginate solution and the solution with calcium chloride solution added, it is known that the solution is changed from a Newtonian liquid to a non-Newtonian liquid when calcium chloride solution is added. Since the attenuation coefficient of microbubble dispersion is proportional to the number of microbubbles, the disappearance of microbubbles lowers the attenuation coefficient. Therefore, in this study, the attenuation coefficient is used as an estimating parameter for the lifetime of microbubbles.
|ジャーナル||Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers|
|出版ステータス||Published - 1996|
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