Physics of diffuse optical imaging

Diffüse optical tomography (DOT) is a functional imaging modality which con-sists of transilluminating of a volume. This diagnosis technique is particulary usefulfor characterizing thick tissue especially for breast tissue. By using model based im-age reconstruction, DOT provides us with the map of tissue properties such as totalhemoglobin concentration and blood oxygen saturation via absorption coe±cient. Be-sides the image of the absorption property of the interior of the breast, DOT givesinformation about cellular and subcellular changes with the aid of scattering coefficient. Even though DOT is relatively low cost, non-invasive, and capable of measuringtissue hemodynamics, it has a drawback of having insu±cient spatial resolution be-cause of the nature of light when scattered in tissue. Therefore, the accuracy of therecovered optical parameters of the tissue is limited. In this thesis, the theoretical basisof diffuse optical spectroscopy and tomography is outlined. First, this thesis examinesthe theory of the propagation of light in tissue. Subsequently, it describes theoreticalbackground of the image reconstruction of di®use optical spectroscopy and tomogra-phy. Finally, the concepts of dual modality and pharmacokinetics model which playan important role in improvement of DOT are presented by using some fundamentaltechniques and methods.