Research and development of a sonothrombolysis equipment

Abstract

Based on data released in 2018 by the World Health Organization, heart disease is the leading cause of death in the world. One of the main reasons for this high mortality rate is the lack of a fast intervention, especially in cases of myocardial infarction diagnosis, where prolonged lack of blood flow, caused by clots (thrombi), can cause irremediable heart muscle loss. Given the relevance of the theme, considering the high loss of lives, new techniques are being tested aiming to reduce the fatality rate of these cases. Sonothrombolysis is a medical technique that uses ultrasound waves, together with the application of microbubbles in the bloodstream and the use of fibrinolytic drugs, to reduce thrombi in the coronary arteries, in patients diagnosed with infarction, promoting an increase in the patency of these arteries. The energy generated by the stable and inertial cavitation of the microbubbles in the region of the thrombi, caused by the mechanical waves of the ultrasound, is the main cause of their rupture. Due to the lack of specific ultrasound equipment for this technique, conventional diagnostic devices are being used, which reduces its efficiency, since the operating parameters were not designed to produce an adequate energy level in the region of interest for a more effective action of cavitation of microbubbles. It is supposed, therefore, that the use of specific ultrasound parameters, from an equipment designed for the use of such technique, would lead to an improvement in its efficiency. This work aims to study these parameters to define a better arrangement of ultrasound transducers, their frequency of operation, pulse length and acoustic intensity, with the related development of an electrical circuit and embedded software, which enable such implementation. The study of the parameters will be done through computer simulations considering a region with similar characteristics to those of the heart, maintaining the safety standards for the use of diagnostic ultrasound. It is expected, as a result of this research, to enable assembling a prototype of a specific therapeutic ultrasound equipment to be used for sonothrombolysis. (AU)