The method involves providing a thermal effect parameter (T) and a mechanical effect parameter (M) in a tissue (16), and sequentially radiating ultrasound pulses with respective pulse width into a tissue (16). A pulse duty factor of the ultrasound pulse is adjusted depending on thermal or mechanical effect parameters of the ultrasound. The pulse duty factor is set depending on the thermal and mechanical effect parameters. An ultrasonic head (2) is activated and deactivated for radiating of ultrasound pulses with the set pulse duty factor. Independent claims are also included for the following: (1) a device for radiating ultrasound into a tissue (2) a computer program product comprising a computer program executed on a computer for implementing a method of controlling a radiation unit for radiating ultrasound into a tissue.
