THE METHOD OF CONTACT DETERMINING OF ULTRA-WIDEBAND ULTRASOUND HEAD OF THE THERAPEUTIC DEVICE WITH THE HUMAN BODY
[3. Технические науки]
Автор: Dovzhenko O.P., National Technical University of Ukraine "Ihor Sikorsky Kyiv Polytechnic Institute", Kyiv, Ukraine; Marchenko O.T., Ph.D., TECHNO-MED Ukraine LLC, Kyiv, Ukraine; Yakunina N.O., Ph.D., National Technical University of Ukraine "Ihor Sikorsky Kyiv Polytechnic Institute", Kyiv, Ukraine; Lukyanenko E.V., National Technical University of Ukraine "Ihor Sikorsky Kyiv Polytechnic Institute", Kyiv, Ukraine
Treatment and improvement of human skin is one of the most important tasks of modern dermatology and cosmetology. Ultrasound devices (UD) are widely used for many medical and cosmetology procedures. The working tool of UD is an ultrasound head (UH), which creates ultrasound vibrations and transmits them to the patient's body. Usually, these ultrasonic vibrations have one or more frequencies, the values depends on the characteristics of the piezoelectric material used in UH. The ultrasound intensity of UD is 0.1 ... 1.0 W/cm2.
Different methods are used to control the contact of the UH with the patient's skin to measure the exact time of the procedure. The most traditional is the control of the current flowing through the UH. This method is effective when UH using piezoelectric materials with well-defined resonant properties, in which the quality factor at resonance frequencies depends significantly on how well the UH contacts the patient's skin.
The authors have developed, manufactured and tested the sample of UD, was applied the ultra-wideband ultrasound signal with frequency range of 1...25 MHz with an intensity on the skin surface of 1 mW/cm2. A piezo film was used as a piezo transducer, which had no resonant properties. Therefore, in contrast to classical methods, ultrasonic signals reflected from the patient's body were used to control the contact of the UH with the patient's skin. To implement this method, the emitting and receiving elements, separated by an insulator, were placed on the working surface of the UH (Figure 1).
Figure 1. The working surface of the UH of the developed UD
If the UH is in good contact with the human body the part of the ultrasound signal created by the emitting element is reflected from the skin structures and reaches the receiving element, which converts the ultrasound signal into an electrical one.
A simplified block diagram of the developed UD is shown at Figure 2.
Figure 2. Simplified block diagram of the developed UD
The work algorithm of UD is following. A pulsed electrical signal from a power amplifier is applied to the emitting element of the UH, which amplifies the output signal of the digital-to-analog converter controlled by the controller. The signal from the UH receiving element goes the signal amplifier, and then, with the help of an analog-to-digital converter, it reaches the controller, which, after analyzing the signal parameters, determines the UH contact with the human body and continues the procedure time on the time indicator or stops it. To prevent false measurement results due to electromagnetic interference at ultrasound emission, the receiving element of the UH is shunted by the key. The operation of the signal amplifier is also blocked this time period.
Tests of the sample of the developed UD confirmed its high informativeness and reliability, which are based on the use of developed circuit-technical solutions and work algorithms.
List of used sources:
1. Belovol A.N., Tkachenko S.G., Tatuzyan E.G. Physiotherapy in cosmetology: textbook on the elective course / KHNMU, Kharkiv, 2015. – 133p.
2. Tereshchenko M.F., Tymchyk G.S., Chuhraev M.V., Kravchenko A.Y. Ultrasonic physiotherapeutic apparatus and devices: monograph /. KPI named after Igor Sikorskyi, Kyiv, 2018. – 180 p.