Temperature elevation generated by a focused Gaussian beam of ultrasound

The steady state temperature elevation generated by a focused Gaussian beam, including the effect of perfusion, has been calculated along the beam axis. The medium is assumed to be a homogeneous absorbing one. The results indicate: (1) The temperature rise is an increasing function of the intensity gain of the focusing transducer, but never seems to exceed twice that at the interface of the transducer and the medium generated by its unfocused counterpart; and (2) The temperature rise at the interface of the transducer and the medium is not affected significantly by focusing.