Theoretical Model And System Of Mesoscopic Fluorescence Molecular Tomography

Mesoscopic fluorescence molecular tomography is an emerging optical molecular imaging technology that fills the gap between microscopic fluorescence molecular imaging technology and macroscopic fluorescent molecular imaging technology.Compared with macroscopic fluorescence molecular imaging technology,mesoscopic fluorescence molecular tomography technology can provide higher resolution.Compared with microscopic fluorescence molecular imaging technology,mesoscopic fluorescence molecular tomography technology has a deeper imaging depth.To make the mesoscopic fluorescence molecular tomography technology better applied to brain functional imaging,early detection of tumors,drug research and many other biomedical research,it is urgent to establish a highly accurate and efficient mesoscopic fluorescence molecular tomography theoretical model and a high-performance mesoscopic fluorescence molecular tomography imaging system.This article mainly focused on the above two aspects.First,the Monte Carlo models that can be applied to fluorescence molecular tomography was studied.Based on the theory of radiation transmission,different Monte Carlo models were deduced,and the applicability of the path-history-based fluorescence Monte Carlo model for fluorescence molecular tomography was evaluated.The research results indicated that three perturbation fluorescence Monte Carlo models are equivalent to each other in Continuous Wave when the absorption coefficient of the background medium in the fluorescent zones is negligible and the decoupled fluorescence Monte Carlo model is the most suitable model for fluorescence molecular tomography.To obtain high-precision mesoscopic fluorescence molecular tomography results,the mesoscopic fluorescence molecular tomography based on decoupled fluorescence Monte Carlo model was proposed.For the first time,the decoupled fluorescence Monte Carlo model was used for forward simulation and image reconstruction of mesoscopic fluorescence molecular tomography.The simulation results showed that the mesoscopic fluorescence molecular tomography based on the decoupled fluorescence Monte Carlo model can obtain high-precision forward simulation and image reconstruction results.To improve the image reconstruction efficiency of mesoscopic fluorescence molecular tomography,the three-level parallel architecture was developed,and the optimization processing method based on three-level parallel architecture to efficiently store,read/write,and transfer the data was proposed.At the same time,to solve the problem of large amount of data in the image reconstruction of mesoscopic fluorescence tomography,the historical path preprocessing method was proposed to compress data volume.The simulation results verified the effectiveness of the above method in reducing the image reconstruction time of mesoscopic fluorescence tomography.Finally,the mesoscopic fluorescence molecular tomography imaging system was designed and developed.To achieve fast,large field of view and high sensitivity data acquisition,the semiconductor laser used as light source,EMCCD camera used as detector,and dual axis galvanometer used to scan light source in the imaging system.At the same time,in order to introduce the structural prior information acquired by the Micro-CT system into the image reconstruction of mesoscopic fluorescence molecular tomography,the geometric calibration method for dual-mode imaging system composed by mesoscopic fluorescence molecular tomography system and Micro-CT system was proposed.The experimental results showed that mesoscopic tomography imaging system can achieve lateral and axial resolution of 100-200 microns with 1-3 millimeter imaging depth,and can accurately locate fluorescent targets and quantify concentrations of fluorescent targets.