Portable Laser Speckle Blood Flow Imaging System And Its Experimental Study

Blood perfusion refers to the rate of blood flow through the capillary circulation of an organ or tissue.Changes in blood flow perfusion often correspond to changes in different physiological states.In clinical medicine,studying blood flow perfusion can play a key role in disease treatment,pathological research,and pharmacological research.Currently,blood perfusion has become an important biomedical research data.As a non-invasive,real-time imaging system,laser speckle blood flow imaging can calculate the motion information of a measured object by collecting dynamic speckle generated by its motion,and can provide high-resolution two-dimensional images of blood flow distribution in real-time.The application of laser speckle blood flow imaging technology to real-time high-resolution imaging of blood perfusion has significant advantages over traditional blood perfusion monitoring techniques.In this thesis,based on laser speckle blood flow imaging technology,a blood flow perfusion detection system has been designed and developed.The main tasks are as follows:1.Complete the construction of a portable laser speckle blood flow imaging systemThe portable laser speckle blood flow imaging system is mainly composed of hardware and software systems.The hardware system can be divided into optical system modules,circuit control modules,imaging system modules,and structural design modules.The excitation light source,photodetector,imaging lens,and various optical lenses are selected according to the parameter requirements.In order to achieve the application scenario of the system,the optical path was reshaped and designed.A Galileo type beam expanding and collimating system with a magnification of 9.97 X was designed using Zemax software.The overall optical path was simulated to determine the effect of laser reshaping.A master control module was independently designed to achieve communication and control between various modules through different protocols.Completed the mechanical structure design of the system,modeled all parts through Solidworks software,and integrated the components through mechanical structure design to form an integration.The normal operation and application of a portable laser speckle blood flow imaging system have been realized.The software system can be divided into an operating system and an information management system.Through the software system,the working status of the system can be controlled in real time,and the collected data can be displayed and imaged in real time.2.Optimizing the parameters of laser speckle blood flow imaging systemAfter the portable laser speckle blood flow imaging system was completely built,its stability was tested,and the blood flow perfusion maps of the lower limbs,brain,and body of mice were observed using the system.Then analyze some influencing parameters of the system.In the laser speckle blood flow imaging system,some key parameters have an important impact on the imaging quality.This article explores the impact on the imaging quality of the system from both the signal transmitting end and the signal receiving end.During the observation of mouse brain blood flow status,different variables of brain blood flow images were obtained by controlling the laser light intensity and camera exposure time.The principles affecting imaging were analyzed,and the laser light intensity and exposure time of the portable laser speckle blood flow imaging system were determined.3.Verify the experimental effect of a portable laser speckle blood flow imaging systemIn order to verify whether the system meets the design requirements,a portable laser speckle blood flow imaging system was designed and validated through Post-occlusion reactive hyperaemia.Four healthy adult males with similar skin color were selected to obtain a complete experimental effect diagram and blood flow perfusion curve through the reactive hyperemia experiment after skin occlusion.Through data processing and analysis of the experimental results,the physiological protection mechanism of the experiment was explained.On the other hand,it verifies the scientificity and accuracy of the portable laser speckle blood flow imaging system.In summary,the system developed in this article based on laser speckle contrast imaging technology has the rationality of design and the accuracy of testing,and can perform non-invasive real-time imaging of blood perfusion.At the same time,the system can complete basic biological experiments and collect authentic and reliable data,laying a theoretical and experimental foundation for further research on the system.