ABSTRACT
Since diffuse optical imaging (DOI) is dominated by applications to biomedical problems, the chapter sets out to introduce the key aspects of scattering and absorption in tissue, and to summarize what can be learned from DOI when utilizing its most common experimental realizations (including continuous-wave, and pulsed frequency-domain and time-domain systems). Because photons usually experience strong scattering and absorption in the sample, in both excitation and imaging channels, the mathematical framework for image generation and reconstruction is different from the other laser imaging techniques. Accordingly, in a dedicated section, the modelling of light transport through tissue is addressed, which hinges on the formalistic link between the forward problem (the interaction within the tissue, using analytical, statistical, and numerical methods for its description) and the reverse problem (related to the principles of image reconstruction, including linear and nonlinear image reconstruction algorithms). The remainder of the chapter is dedicated mainly to state-of-the-art clinical applications, including spectrally sensitive diffuse optical tomography for breast cancer diagnosis; or photoacoustic tomography, demonstrating the high spatial resolution capabilities of DOI. The chapter concludes with a few nonclinical examples (such as diagnostic measurements for fruits), and a brief comparison of DOI with other medical imaging techniques.
