ABSTRACT
With ultrasound gaining more ground in cancer diagnosis and therapy, ultrasound contrast agents (UCAs aka bubbles) are receiving unprecedented attention in the scientifi c community. Other than the conventional application, UCAs also serve as including nuclei for cavitation in ultrasound mediated drug delivery and carriers for drug and/or gene delivery. While microbubbles are widely studied and commercially available for clinical (particularly in Europe and Asia) and experimental use, the utilization of the nanometric version of these bubbles in cancer diagnosis and therapy is still in relatively early stages of development. Despite the understanding that nanobubbles are more desirable for disease targeting, both passively and actively, the lag in nanobubble development in cancer medicine can be largely attributed to challenges with nanobubble echogenicity at clinically relevant ultrasound frequencies (3-20MHz), and lack of commercial availability due to diffi culty in cost effective scale up formulation techniques, among others. This chapter provides comprehensive information on topics including the acoustic behavior of bubbles within the ultrasound fi eld, the major types of nanobubbles currently under development, their formulation methods and their working principle in cancer diagnosis and therapy.
