Monitoring of the effectiveness of the interstitial RF electromagnetic wave thermal therapy by shear modulus reconstruction

Abstract

We have previously developed an ultrasonic strain measurement-based shear modulus reconstruction technique. The iterative RF-echo phase matching method uses successively acquired RF-echo data frames for measuring strains generated in vivo in soft tissues due to spontaneous heart motion and/or externally applied pressures. Together with development of a suitable configuration technique for mechanical sources and reference regions, we developed a numerical method for stably reconstructing the globally relative shear modulus distribution with respect to reference shear moduli from the measured strain data. As the elasticity of soft tissues changes on being heated, we propose that the developed shear modulus reconstruction technique can be used as a monitoring technique for the effectiveness of thermal therapy. We applied the reconstruction technique to interstitial RF electromagnetic wave therapy. To verify the feasibility we conducted in vitro experiments using fresh calf liver.