Optimal suppression of therapeutic interference for real-time therapy andimaging with an integrated HIFU/imaging transducer

In ultrasound imaging-guided HIFU (High-Intensity Focused Ultrasound)treatment by using an integrated HIFU/imaging transducer, the reflectedtherapeutic wave significantly interferes with the imaging signal duringsimultaneous therapy and imaging. In order to obtain ultrasound B-mode imageswith acceptable resolution, these interferences should be minimized at least to40 dB level. It was previously demonstrated that coded excitation with fixednotch filtering could reduce the sidelobe level of the HIFU interference tolower than 40 dB while normal short pulse excitation showed higher than a 30 dBsidelobe level due to remnant ripples after fixed notch filtering. In thisarticle, we presented that both HIFU noise and remnant ripples for short pulseexcitation could be minimized by using an adaptive HIFU interference suppressiontechnique. A prototype integrated HIFU/imaging transducer with cylindricallyshaped aperture was fabricated and A-mode signal and B-mode image experimentswere performed to prove the feasibility of the proposed method experimentally.