Confocal Optical Measurements in Highly Scattering Media: Light Path Using Photon Time-of-Flight

摘要

The long-term goal of this work is to gain a better understanding of scattering in dense media. This information will aid in the development of new clinical tools for quantitative, depth-resolved measurements of metabolism. Constituents such as hemoglobin, myoglobin, and cytochrome oxidase are useful to characterize respiration in tissue using the red and near-infrared spectral region. Tissue scatter causes variations in the optical path of light propagating through it. Scattering in the near-infrared by tissue is highly forward-directed. Forward scattering can be thought of as light propagating through a sea of randomly oriented weak lenses. It has been demonstrated that these forward-scattered photons (ballistic and snake-like photons) are highly directed along a given path as dictated by the optical geometry. Confocal optical systems are known to restrict the light path in mildly scattering samples. Our group has been examining the application of confocal optics in highly scattering samples.