High power and therapeutic ultrasound

Beam Predictability for high power transducers

Focus control is an important element in designing a transducer for medical therapy: it is essential to accurately control the treatment zone and to thus protect the healthy tissue.

The intrinsic features of Imasonic's piezo-composite structure enable radial modes to be reduced, thus favoring the vibration according to the thickness mode. The electro-acoustic response obtained is thus very close to the theory and the acoustic field does not present any hot points outside the focal point. See the illustration below.

Cathignol et al., Comparison of acoustical fields radiated from piezoceramic and piezocomposite highly focused transducers, J. Acoust. Society of America 1999

Simulated Beam

Simulated radiated field

PZT Transducers

The figures below show clearly the limitations of PZT transducers through the possible generation of unexpected hot spots that may cause unexpected and uncontrolled lesions in tissues. This phenomeneon is mainly due to the generation of lamb waves inside the PZT plate.

Piezocomposite transducer

The figure below shows the very good beam predictability with piezocomposite transducers

Experimental radiated field, very close to the simulation