Patent ID: 8702630

Claim:
A method for driving an injection device for injecting ultrasound into a tissue, the ultrasound having a predetermined thermal effect and a predetermined mechanical effect in the tissue, the method comprising: predetermining a mechanical effect parameter for the mechanical effect; predetermining a thermal effect parameter for the thermal effect; defining a duty ratio as a function of the thermal effect parameter and of the mechanical effect parameter; injecting a sequence of ultrasound pulses, the sequence comprising first ultrasound pulses and second ultrasound pulses respectively having different ultrasound frequencies, the sequence having a single first ultrasound pulse following a single second ultrasound pulse and the single second ultrasound pulse following the single first ultrasound pulse; wherein one of the ultrasound frequencies is an integer multiple of the other ultrasound frequency utilizing the injection device, each of the ultrasound pulses comprising a pulse width, wherein the duty ratio of the ultrasound pulses at the predetermined ultrasound frequency is set as a function of the thermal and mechanical effect parameters of the ultrasound, and the duty ratio is defined as a ratio of a first time period of emission of one ultrasound pulse at the predetermined frequency divided by a second time period, the second time period being a sum of the first time period and a time period following the first time period and having no ultrasound emission, and activating and deactivating the injection device for injecting the ultrasound pulses having the duty ratio, wherein an amplitude of an emitted ultrasound power of the ultrasound pulses is utilized as the mechanical effect parameter or an emitted power of the ultrasound pulses is utilized as the thermal effect parameter.