Design of Cooling System of Laser Scalpel

Abstract

During neurosurgery, the contact laser scalpel needs to perform hemostatic ablation of surface lesions, and the temperature gradient formed on the probe must be very steep to achieve precise vaporization. However, the cooling speed of the laser probe has low stability. When the temperature of the probe is 80°C or above 100°C, it will cause problems such as adhesion and carbonization of human tissue. In order to improve the stability of the temperature control of the laser probe and form an accurate temperature gradient, three refrigerants, air, CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> and physiological saline, are used to realize the temperature adjustment of the probe. The low-power microcontroller TM4C123AH6PM is adopted as the main controller of the cooling system. The human-machine interaction is carried out through the touch screen to realize the display of cooling system data. Fuzzy PID control algorithm is adopted to realize the accurate adjustment of the flow rate of gas and liquid and the temperature of the probe. The experimental results show that the maximum error rates of the measured and set values of the flow rate of gas and liquid are 5.5%, 6.4% and 3.3%, respectively, and the average error is about 5%; the maximum error between the measured value and the set value of the temperature of the laser probe is ±0.1°C. The system ensures that the cooler outputs a highly stable flow rate of gas and liquid, ensures high accuracy of the temperature gradient of the laser probe and high stability of the temperature control.