3D modeling for solving forward model of no-contact Fluorescence Diffuse Optical Tomography method

摘要

This paper presents detailed computational aspects of a new 3D modeling for solving the direct problem in a no-contact time-resolved Fluorescent Diffuse Optical Tomography (FDOT) method that rely on near-infrared scattered and fluorescent photons to image the optical properties and distribution of fluorescent probes in small laboratory animals. An optical scanner allowing performing in-vivo measurements in no-contact scheme was built in our laboratory and is presented. We use the three-dimensional Finite Element Method (FEM) to solve the coupled diffusion equations of excitation and fluorescence photons in highly scattering objects. The computed results allowed yielding photon density maps and the temporal profiles of photons on the surface of the small animal. Our 3D modeling of propagation of photons in the void space between the surface of the object and the detectors allows calculating the quantity of photons reaching the optodes. Simulations were carried-out on two test objects: a resin cylinder and a mouse phantom. The results demonstrate the potential applications of the method to pre-clinical imaging.