P2B-8 Effect of Acoustic Insonation Parameters on Ultrasonic Contrast Agents Destruction

Characterization of ultrasonic contrast agents (UCAs) destruction provides important information for the design of contrast-assisted perfusion imaging. In this paper, we proposed an acoustical method to demonstrate the relationship between different acoustic exposure conditions and the degree of UCAs destruction. The method also provides a simple and convenient way to determine the bubble destruction threshold. The insonation parameters include transmission pressure, pulse frequency and pulse cycles. The term of destruction percentage (DP) represented the ratio of backscattered power with and without acoustic insonation. The results showed that the DP increased with decreasing pulse frequency, but with increasing transmission acoustic pressure and pulse cycle. Over 90% UCAs could be destroyed at 0.15, 0.4, 0.7 and 0.8 MPa in 1, 2.25, 5 and 7.5 MHz pulse under 10-cycle pulses condition, respectively. In addition, there was an exponential relationship between DP and acoustic pressure, pulse cycle and thus the UCAs destruction threshold parameters could be predicted by the exponential curve. The UCAs destruction threshold is not related to the mechanical index. Potential applications of this method include UCAs high resolution destruction/replenishment imaging model, microbubble cavitation, sonoporation in drug delivery and gene therapy