Effect of multiple layers on diffuse optical tomography

In this work we investigate the effect of a layer on Diffuse Optical Tomography of tissue. Such layers could be tissue structures (such as the skin or a fat-layer) or layers formed by compression plates. Our analysis uses an analytical forward model that is based on the angular spectrum representation of the propagating photon density wave in a diffuse medium. The inversion employs a standard perturbation expansion based on the Rytov approximation that is uses appropriate volume segmentation and solved using the algebraic reconstruction technique. The results demonstrate that the effect of biologically relevant multi-layer schemes can lead to significant reconstruction errors both in terms of quantification and positional certainty. The work is focused on geometries and optical properties typical to the human breast, however the results are general and can apply to other tissue as well.