Light Dosimetry Of Bone Tissue Ablation In Laser Ear Surgery

With the development of laser technology, laser ablation of hard tissue such as bonetissue is being used more and more widely for applications in bio-medical domain.Considering the importance of light dose in laser ablation, the research on light dosimetryof bone tissue ablation in laser ear surgery was developed preliminarily in theory andexperiment.Firstly, a short introduction to the situation and outlook of application of laser lightin ear surgery was briefly outlined. The status of light dosimetry of bone tissue ablationwas reported. Then the purpose to this study was also presented.Secondly, the basic concept related to bio-tissue ablation was given. The ablationmechanism related was discussed. The tissue model and numerical model of laser ablationwere established. Then based on tissue property and laser parameter, the light dosimetryof bone tissue ablation was illustrated.Thirdly, investigations on ablation of porcine temporal bone with pulse CO₂ laser,pulse Er:YAG laser and pulse Ho:YAG laser in vitro were presented. The ablation effectat different fluence was compared and analysed. The experiments obtained the trend ofcrater diameter and depth with energy density and found the ablation threshold for threelasers respectively.Finally, laser ablation of vitro porcine temporal bone was studied with continue CO₂laser, where bone tissue was moved along the line. The experiments obtained the trend ofcut width and depth with energy density. The measurements of cut depth with OCT andhistology were compared and analysed.