Measurements of young´s modulus of viscoelastic medium using a laser-induced microbubble under acoustic radiation force

An approach to assess the mechanical properties of a viscoelastic medium using laser-induced microbubbles is presented. A 532 nm wavelength nanosecond pulsed laser beam was focused into a phantom to create a microbubble at the desired location. A 3.5 MHz ultrasound transducer was used to generate acoustic radiation force to excite the laser-induced microbubble. Motion of the microbubble was tracked using a 25 MHz imaging transducer. An agreement between a theoretical model of bubble motion in viscoelastic medium and experimental measurements was demonstrated. Young´s moduli reconstructed using the laser-induced microbubble approach were compared with those of direct measurements. Thus, the proposed approach can be used to assess the mechanical properties of viscoelastic medium such as soft tissue.