Correction method of surface effects in infrared laser transillumination CT imaging

A reconstruction method for transillumination laser CT using optical heterodyne detection is proposed. Laser CT does not obey the Radon transform due to surface effects, which occur as results of refractive index mismatch and roughness of surface, and bring about annulus artifact and impair quantitative accuracy of a reconstructed image. Optical attenuation with surface effects is described using a model function with respect to an incident angle. This reconstruction produces a least squares problem incorporating the surface effect, which is solved via the conjugate gradient method. The method is applied to data from a acrylic physical phantom containing Intralipid-10% solution in various concentrations for demonstrating the effectiveness of the proposed method in terms of morphological and quantitative information. The CDI method is proved to have an excellent quantitative accuracy.