Powerful focused ultrasound: nonlinear effects, excitation of shear waves and medical diagnostics

Phenomena that accompany focusing of powerful ultrasonic beams have been reviewed. А possibility to increase the radiation force and to contract the region of its localization in а nonlinear focusing operation has been shown. А method has been proposed to produce shock fronts in the focus due to the synthesis of а special initial profile which enaЫes the wave energy to Ье transported with almost no losses and to organize its local liberation in the focus bу "switching on" nonlinear absorption. А theory has been developed of а new higbly sensitive diagnostic method based upon remote excitation of low-frequency shear waves in soft biological tissues Ьу means of powerful modulated ultrasound.