Imaging and monitoring non‐cavitating focused ultrasound lesions using light and sound.

Abstract

Acoustically imaging non‐cavitating HIFU lesions is challenging due to the relatively weak contrast between normal and necrosed tissues. However, thermal lesions posses optical scattering and absorption characteristics that can differ significantly from surrounding tissue. Acousto‐optic (AO) sensing refers to the detection of phase modulated photons generated by the nonlinear interaction of diffuse laser light (532 and 1064 nm) and a focused ultrasound beam. AO sensing in excised chicken breast exposed to HIFU (1.1 MHz) is used to sense the onset and spatial extent of lesion formation in real time and to image an existing lesion after HIFU exposure. We also demonstrate that the AO signal can be used to provide real‐time feedback in order to more effectively control the duration of the HIFU exposure. [Work supported by the Center for Subsurface Sensing and Imaging Systems (NSF ERC Award No. EEC‐9986821).]