Photoacoustic tomography as a method to estimate the optical fluence distribution in turbid media.

Currently, there are no non-invasive experimental methods available for measuring optical fluence distributions in tissue. We present photoacoustic tomography (PAT) as a method to approximate the relative optical fluence distribution in a homogeneous optically scattering medium. Three-dimensional photoacoustic images were captured with a near-full view PAT scanner in phantoms with known optical absorption and scatter properties.

Approaching closed spherical, full-view detection for photoacoustic tomography.

Significance: Photoacoustic tomography (PAT) is a widely explored imaging modality and has excellent potential for clinical applications. On the acoustic detection side, limited-view angle and limited-bandwidth are common key issues in PAT systems that result in unwanted artifacts. While analytical and simulation studies of limited-view artifacts are fairly extensive, experimental setups capable of comparing limited-view to an ideal full-view case are lacking.

Single-shot 4-step phase-shifting multispectral fringe projection profilometry.

Phase-shifting profilometry (PSP) is considered to be the most accurate technique for phase retrieval with fringe projection profilometry (FPP) systems. However, PSP requires that multiple phase-shifted fringe patterns be acquired, usually sequentially, which has limited PSP to static or quasi-static imaging. In this paper, we introduce multispectral 4-step phase-shifting FPP that provides 3D imaging using a single acquisition.

Multispectral intravital microscopy for simultaneous bright-field and fluorescence imaging of the microvasculature.

Intravital video microscopy permits the observation of microcirculatory blood flow. This often requires fluorescent probes to visualize structures and dynamic processes that cannot be observed with conventional bright-field microscopy. Conventional light microscopes do not allow for simultaneous bright-field and fluorescent imaging.

Single-shot detection of 8 unique monochrome fringe patterns representing 4 distinct directions via multispectral fringe projection profilometry.

Spatial resolution in three-dimensional fringe projection profilometry is determined in large part by the number and spacing of fringes projected onto an object. Due to the intensity-based nature of fringe projection profilometry, fringe patterns must be generated in succession, which is time-consuming. As a result, the surface features of highly dynamic objects are difficult to measure.