Transient subharmonic and ultraharmonic acoustic emission during dissolution of free gas bubbles

This work concerns the study of free gas bubble behavior, a basic step in contrast agent study. In order to improve the understanding of microbubble-ultrasound interaction, we propose an acoustic dynamic observation of microbubble behavior performed by a high frame-rate acquiring and processing system. Results from ultrasonic observations of free gas microbubbles are discussed and compared with theoretical simulation. Peculiar radio frequency (RF) echo signals back-propagated from bubbles during dissolution tip to their destruction are shown and their behavior is discussed. In particular, the different orders of subharmonic emissions related to changes in bubble sized; during dissolution were observed.