Research On And Measure Of Transmyocardial Laser Revascularization

In this dissertation the developments of laser biomedicine, biomedical detection and metrology and transmyocardial laser revascularization(TMLR) were summarized and the problems in research and clinical application of TMLR were indicated. The following researches have been done in order to solve the problems:The advantages and disadvantages of all kinds of laser revascularizations were analyzed according to the rules of interaction between laser and myocardium and the principle of laser revascularization. How to select duration of laser irradiation and the density of power was studied according to the physiological principles.The rules of interaction between laser and myocardium were studied with the help of the diffuse approximation and the Monte Carlo simulation according to the theory on photon transmission and the characteristics of myocardial structure. At the same time, the theoretical model of the infrared laser revascularization in myocardium and the theoretic model for heat exchange to cause thermal lesion round laser channel were built in this dissertation. These models have been calculated and tested with the help of computer and experimental technology. Based on these, the "biologic filter" for laser revascularization was firstly put forward and the effect of "biologic filter" was detected with animal experiment.The quality of CO₂ laser revascularization in myocardium was examined with the help of the epicardial electrocardiogram and the pigmentation of myocardium and the radioactive biologic particulates and the casting myocardial vas and so on. The therapeutic principle of TMLR was studied according to all kinds of experimental results and the rules of interaction between laser and myocardium and the theoretical model of laser revascularization in myocardium.The following innovative achievements have been acquired in our research.1. The causes to induce the myocardial lesion round the laser channel and the "evase orifices" of the laser channel were seriously anatomized and the "biologic filter" was devised for TMLR for the first time. The "biologic filter" can improve quality of laser beam and remove the "evase orifices" from the laser channel and minish myocardial lesion round the laser channel so that the quality of laser revascularization could be enhanced. The same research reports have not been found in the world up to now.2. The quantitative relationship was fetched that depth and aperture of infrared laser channel in myocardium depended on the output power, the facular radius, the duration of laser irradiation, as well as depended on the absorbing coefficient and the specific heat and the potential heat and the density and the thermal conductivity and the thermal diffusivity of myocardium. The quantitative relationship was validated and amended according to experimental results. The innovative researches established the base for optimizing the project of clinic therapy and set up the intelligentized device of laser revascularization in myocardium.3. The theoretic model for heat exchange to cause myocardial thermal lesion round infrared laser channel was established according to the principles for infrared laser revascularization in myocardium. The regularity for infrared laser revascularization to cause myocardial thermal lesion was detailedly studied with the finite element method and computer software program by author. The regularities of heat exchange's causing myocardial thermal lesion were found. This research provided theoretic basis for minishing thermic trauma caused by laser in clinic application of TMLR.4. The therapeutic principles of TMLR were seriously studied and my points of view were given according to all kinds of experimental results. My points of view are that different experimental parameters would cause differences of quality of laser revascularization so that the therapeutic principles of TMLR will be different.The theoretical model was combined with computer simulation to study TMLR for the first time and some useful conclusions were obtained.The innovative achievements are theoretically significant, very worthy and useful to the research of the principles and the clinic application of TMLR.