Thermal holographic patterns for ultrasound hyperthermia

Abstract

Holograms can shape wavefronts to produce arbitrary acoustic images. In this work, we experimentally demonstrate how acoustic holograms can produce controlled thermal patterns in absorbing media at ultrasonic frequencies. Magnetic resonance imaging (MRI)-compatible holographic ultrasound lenses were designed by time-reversal methods and manufactured using 3D-printing. Several thermal holographic patterns were measured using MRI thermometry and a thermographic camera in gelatin-milk phantoms and in an ex vivo liver tissue. The results show that acoustic holograms enable spatially controlled heating in arbitrary regions. Increasing the temperature using low-cost and MRI-compatible holographic transducers might be of great interest for many biomedical applications, such as ultrasound hyperthermia, where the control of specific thermal patterns is needed.