A Study Of Cutting And Hemostatic Scalpel Based On Laser Heat Source

Laser scalpels have been widely used in clinics. The thermal effect is the keymechanism in intense laser interaction with tissue in the laser surgery. The thermaleffect enables the tissue to achieve vaporization or coagulation temperature tocutting and hemostatic. There are still problems such as the selective dependence tolaser wavelength of tissue, the instability of cutting ability and the unreliability ofhemostatic effect for vascular of larger diameter.The main content of the first part of this thesis is that intensity changes ofcollimated transmission light, diffuse transmission light and diffuse reflection lightof albumen, dog livers, dog kidneys, dog muscles and rat muscles at650nmlow-power laser irradiation during the heating were measured by theintegrating-sphere system in the experiment. The calculated optical parameterschanges with temperature suggested that absorption and scattering coefficientsincreased during the tissue thermal denaturation process. The changes of opticalparameters affect the results of laser-tissue interaction, which causes the cuttingcapacity unstable.The main content of the second part of this thesis is that samples of muscles andblood vessels from rabbits and dogs were heated in constant temperature water bath.The impact of thermal effects on hemostasis was analyzed by comparing the changesof samples in physical dimensions and pathological forms before and after thermaldenaturation. Morphological changes of muscles after headed had few effects onhemostasis. Thermal denaturation made vascular wall thickened and wrinkled whichassisted hemostatic. When stanching large diameter vessels using laser, blood clots could not completely stop blood vessels from bleeding. External pressure is neededto enclose blood vessels.The main content of the third part of this thesis is that the energy-based surgicaldevice with laser heat spot was set up using1064nm wavelength solid-state Nd:YAG laser. The scalpel based on a laser heat source used graphite material as thelaser absorption medium, which had well vaporization cutting capability on softtissue. And the cutting depth was deeper than non-contact laser scalpel of the samepower.The main content of the fourth part of this thesis is that the control system of thelaser surgery device was designed and implemented. A LCD touch-screen and aMCU controller were used to control the working state of the acousto-optic switch.The acoustic-optic switch controlled the average laser pulse output power. Adjustingthe duty cycle of the output laser pulse can control the average laser output powerand temperature of scalpel head based on a laser heat source.This thesis suggested corresponding solutions to a few issues that existed inlaser surgery based on experimental studies and theoretical analysis. According tothe research results, the design of an energy surgical device based on a laser heatsource including a control system was implemented.