Design And Implementation Of Diffuse Optical Tomography Software Framework With CPU-GPU Acceleration

Compared with traditional imaging technologies,as a new type of near-infrared tissue functional imaging technology,diffuse optical tomography(DOT)possesses the advantages of high specificity,low cost,and without invasiveness.DOT has a wide application prospect in the early detection of breast cancer,neoadjuvant chemotherapy,drug evaluation,etc.However,DOT reconstruction is a complex mathematical iterative process with a large amount of computation.Thus,the thesis aims at developing an accurate and efficient software for DOT reconstruction,which mainly includes the three aspects as follows:DOT reconstruction algorithm design.In accordance with the reconstruction principle of DOT,the implementation scheme of reconstruction algorithm is designed.As for the forward and inverse problems in the reconstruction process of DOT in Continuous Wave(CW)and Frequency Domain(FD),which includes the stiffness matrix calculation,Jacobian matrix calculation,light source vector calculation and the solving process of node photon density.The specific calculation scheme has been designed based on the Finite Element Method(FEM).DOT acceleration scheme design.Based on the parallelism of the reconstruction algorithm,the accelerated schemes for the reconstruction of CW DOT and FD DOT are proposed and verified.According to the Central Processing Unit(CPU)and the Graphic Processing Unit(GPU),the stiffness matrix calculation,the Jacobian matrix calculation,and the updated quantity calculation in the DOT reconstruction have been accelerated,gaining a large speed-up ratio.In the reconstruction of the three-dimensional CW DOT,the speed-up ratio of the 5292 pairs of source-detector(SD)pairs reaches 22.50,when the reconstruction grid contains 61322 nodes,while that of the 2916 SD pairs is 17.78 when there are 61322 nodes in the mesh in the reconstruction of the three-dimensional FD DOT.DOT reconstruction software development.Based on the platform of Visual Studio,a set of software in C++ version has been developed for DOT reconstruction,with a wide range of functions,which is conducive to reconstruction of the two-dimensional CW,three-dimensional CW,two-dimensional FD and three-dimensional FD DOT.Through the multiple sets of CW,FD simulation or phantom experiments,the reconstruction accuracy of the software is tested.In addition,under various reconstruction scales and reconstruction types,the NIRFAST(Near Infrared Fluorescence and Spectral Tomography),afrequently-used reconstruction software,is adopted to conduct the speed contrast experiment with the reconstruction software of DOT,which shows that the software operates faster more than 10 times than NIRFAST in different experimental conditions.