Quantification of Cell Death due to Ultrasound Therapy with Contrast Agents

In this work, the authors conduct in vitro studies of the effects of ultrasound (US) therapy with contrast agents. Both microbubbles with a phospholipid shell alone and microbubbles encapsulated with a polymer capsule were utilized as contrast agents. With increased concentrations of microbubbles, more cell death occurred due to the increased number of acoustic shock waves if the pressure is above the inertial cavitation threshold. When one micron microbubbles are enclosed in a 3-5 micron polymer capsule, no cell death occurredt any pressure or concentration. This increased cell viability is the result of an increase in the inertial cavitation threshold due to the coencapsulation of the microbubbles. The coencapsulated microbubbles proved safer than commercial contrast agents for imaging without sacrificing the quality of the image.