Study On Safety And Application Of Thulium Laser In The Treatment Of Central Airway Malignant Tumors : A Systematic Ex-vivo Evaluation

Objective: Objective: To study the cutting efficiency,vaporization efficiency,hemostasis effect and thermal damage depth of thulium(Tm)laser technology with different diameter fibers and different powers on lung malignant tumors,in order to understand the effectiveness and safety of thulium laser.Method: Select 42 SPF C57BL/6 mice(6 weeks old,male)to establish a mouse lung cancer model.The tumor diameter was measured regularly,and the experiment was started when the tumor diameter reached 15 mm.The mice were randomly divided into 7 groups,respectively 365μm 5W thulium laser group,365μm 10 W thulium laser group,365μm 20 W thulium laser group,550μm 5W thulium laser group,550μm 10 W thulium laser group,550μm 20 W thulium laser group,30 W argon plasma coagulation(APC)group;Thulium laser and APC act on tumor tissues,measure and record the differences in the observation indicators of each group,then take each group of tumor tissues to make pathological sections,HE stain,observe and measure the depth of thermal damage of each group of tumor tissues under an optical microscope,and perform statistics analysis.Result: Under the condition of the same fiber diameter,the higher the power,the greater the vaporization efficiency and cutting efficiency of the thulium laser;under the same condition of the thulium laser power,the vaporization efficiency and cutting efficiency of the fiber with a diameter of 365μm are less than that of the fiber with a diameter of 550μm,there was a statistically significant difference between each group(P<0.05).There was no significant difference in the maximum thermal damage depth caused by the laser acting on the tumor tissue between the groups(P>0.05);the difference in the hemostatic performance of the laser in each group was not statistically significant(P>0.05);Under the microscope,it can be observed that there is carbonization around the laser cutting of thulium,vacuoles appear in the lower layer,and the heat damage area of the tumor tissue is stained deeper.After laser cutting,the depth of thermal damage on both sides is less than the depth of thermal damage at the bottom,and the difference is statistically significant(P <0.05).Compared with the APC with a power of 30 W and a thulium laser with a diameter of365μm and a power of 10 W,the cutting efficiency and vaporization efficiency of the thulium laser is higher than that of the APC.The difference between the two is statistically significant(P<0.05);Comparing the hemostatic performance and thermal damage depth of the two,it is found that the difference is not statistically significant(P>0.05).Conclusion: The domestic 1.94μm thulium laser is a kind of laser with good vaporization and cutting effect,good hemostatic effect and small damage depth.Compared with APC,it has higher efficiency,shorter treatment time,and no increased risk of heat injury and bleeding.It is an ideal thermal ablation technique for interventional treatment of airway tumors.