Research On Modeling And Optimal Design Of Near-Infrared Light Propagation In Vein Tissue

In recent years,the number of cancer patients have reached 3.929 million per year,and the mortality rate is 170.05 per 100 thousand.Intravenous injection is ones of the most important method in the process of cancer treatment.Due to long-term intravenous treatment,patients have issues such as narrowing,small elasticity,and rigid trunk of the blood vessels,which makes it difficult for medical staffs to puncture the veins.Although researchers at home and abroad have conducted a large number of works about the noncontact vein image,the vein imaging system involves complex optical,electrical,and biological cross-coupling characteristics,leading to the poor imaging quality of patients' blood vessels,poor population adaptability,and high cost.Based on the basic principles of photobiological tissue imaging,therefore,this study uses multi-physics finite element simulation methods considering the optical,electrical,and biological influence factors of near-infrared vein imaging,and the modeling,simulation and optimization of vein imaging.The experimental prototype has been built,and compared against the results of theoretical simulation.The main contents are given as the following four aspects:(1)Aiming at the current status of non-contact research on vein imaging,the literature review analysis method is used to sort out the principles and approaches of vein imaging,focusing on the analysis and summary of performance indicators such as the wavelength,morphology and uniformity of the light source,as well as the interaction between light and biological tissues.Mechanism,clarify the main influencing factors of infrared vein imaging,and formulate research objectives,content and methods;(2)The principle of near-infrared light vein imaging is explained,the absorption,scattering and reflection characteristics of the interaction between infrared light and biological tissues are discussed,combined with the multi-layer biological tissue structure of the hand,the geometric structure of infrared light propagation in biological tissues is given.Material properties,physical equations and boundary conditions provide preliminary preparations for subsequent theoretical modeling and experimental verification;(3)The finite element modeling principle and method of near-red light vein imaging of the hand are proposed.According to the physiological structure of the hand MRI image and the photon radiation transmission equation,the near-red light transmission of the hand is constructed with the help of COMSOL Multiphysics finite element software.The model is validated with the existing Monte Carlo simulation.Furthermore,based on the validated model,the sensitivity analysis of the wavelength,shape and position of the light source for near-red light vein imaging is carried out,and the optimal parameters are given.To provide theoretical guidance for system construction;(4)Combining the above theoretical research,a physical device for vein imaging is built,including two main parts: infrared light source and imaging detection.Among them,the driving circuit of the infrared light LED array and the uniformity of light and the CCD measurement optical path are designed,and combined with MATLAB Graphical user interface programming and other means,integrating the acquisition and processing of vein images,give experimental test results.In summary,the infrared imaging of venous tissue was studied theoretically and experimentally by using the radiation transmission theory of light,the finite element simulation model was given,the venous imaging system was built,and the venous imaging images were obtained,which provides a new method for the venous puncture of medical staff.