PHOTOACOUSTIC IMAGING CONTRAST AGENT AND SYSTEM FOR CONVERTING OPTICAL ENERGY TO IN-BAND ACOUSTIC EMISSION

摘要

The present disclosure provides systems and methods related to contrast agents for photoacoustic and ultrasound imaging. A contrast agent includes a nanoparticle -based contrast medium that is adapted to absorb optical energy and to undergo a phase change upon absorption of a requisite level of optical energy, such phase change being effective to generate nano-bubbles and/or micro-bubbles that resonate at a frequency or in a frequency range. Various constructions of the PA contrast agent are provided including one substance droplets with both absorbing and evaporating capabilities, and multiple-component complexes of one substance with both absorbing and evaporating materials. Highly absorbing nano-particles (such as gold nano-rods) may be coated with an evaporating material. In addition, disclosed agents (including either one substance or multi-component complex) may be encapsulated or coated with an optically transparent and mechanically elastic shell that allows the droplet to expand and form stabilized nano- and/or microbubbles during phase change.