The Research And Design Of Portable Ultrasound Transcranial Stimulation System

Transcranial Ultrasound Stimulation(TUS) technology is a newly developed brain stimulation technique, the ultrasonic energy transmit through the intact skull to stimulate the brain tissue in this technique so as to modulate the brain nerves noninvasively. Comparing with traditional brain stimulation techniques such as transcranial magnetic stimulation, transcranial direct current stimulation, TUS has many advantages such as high spatial resolution, non-invasive and high penetration. What’s more, it has a good compatibility with the functional magnetic resonance imaging and provids good conditions for the accurate positioning of TUS and the neurophysiological research. As a new brain stimulation technique, TUS has already been proved to have two effects on the nervous regulation which are excitation and inhibition. And research results have shown that neither the excitation nor the inhibition will damage the tissue in the area that are stimulated by TUS. We can expect that a lot of headachy neurological diseases in the medical field will usher in a new breakthrough with the use of TUS.Although there are more and more scientists research about TUS, the researches are still in the experimental stage now. Except of the few experiments that are applied to the human brain, most of the experiments are applied to animals. Scientists construct experimental platform, apply the ultrasonic to the animal’s brain and then analyze the biological signal such as Electroencephalography(EEG) and Electromyography(EMG) so as to study the effect of TUS on the brain tissue. Currently, low intensity ultrasound therapy equipments have many limits such as signal function and fixed parameters. They can’t meet the require of multiple adjusted parameters in experimental study and clinical treatment. In order to achieve the multiple adjusted parameters, TUS systems used in animals experiments are all accomplished by constructing experimental platform. The platform includes large function generator, power amplifier, oscilloscope and other equipment, it is bulky, high-cost and not portable.To overcome these shortcomings and deficiencies of the existing technologies and provide a set of experimental equipment for the research of TUS so as to analyze it’s affect on the treatment of brain disease, this study designs a portable TUS system, which includes the driving circuit of the ultrasonic transducer and the ultrasonic echo receiving circuit.The driving circuit of the ultrasonic transducer can drive transducers with different center frequency.The peak to peak value of the voltage(),the fundamental frequency(F), the pulse repetition frequency(PRF) and the pulse duty ratio(D) are adjustable. Meanwhile, the ultrasonic echo receiving circuit receives the ultrasonic echo signal. And the signal transmit through the signal conditioning circuit and the A/D converter circuit.Then the digital signals was send into the computer for display by the signal processing circuit. The filter’s center frequency(F0) and the gain of programmed amplifier(G) are adjustable. We can always ensure the accurate transmition of the ultrasound signals and improve the reliability of the experiment. The interface on PC is based on VC++, users can set the corresponding parameters according to actual needs quickly and observe the received echo signals. The system is simple, reliable, low-cost and have a good industrial value.