Imaging pancreatobiliary ductal system with optical coherence tomography: A review.

An accurate, noninvasive and cost-effective method of in situ tissue evaluation during endoscopy would be highly advantageous for the detection of dysplasia or early cancer and for identifying different disease stages. Optical coherence tomography (OCT) is a noninvasive, high-resolution (1-10 μm) emerging optical imaging method with potential for identifying microscopic subsurface features in the pancreatic and biliary ductal system. Tissue microstructure of pancreaticobiliary ductal system has been successfully imaged by inserting an OCT probe through a standard endoscope operative channel.

Review of speckle and phase variance optical coherence tomography to visualize microvascular networks.

High-resolution mapping of microvasculature has been applied to diverse body systems, including the retinal and choroidal vasculature, cardiac vasculature, the central nervous system, and various tumor models. Many imaging techniques have been developed to address specific research questions, and each has its own merits and drawbacks. Understanding, optimization, and proper implementation of these imaging techniques can significantly improve the data obtained along the spectrum of unique research projects to obtain diagnostic clinical information.

Determination of threshold exposure and intensity for recording holograms in thick green-sensitive acrylamide-based photopolymer.

For optical data storage applications, it is essential to determine the lowest intensity (also known as threshold intensity) below or at which no data page or grating can be recorded in the photosensitive material, as this in turn determines the data capacity of the material. Here, experiments were carried out to determine the threshold intensity below which the formation of a simple hologram--a holographic diffraction grating in a green-sensitized acrylamide-based photopolymer--is not possible. Two main parameters of the recording layers--dye concentration and thickness--were varied to study the influence of the density of the generated free radicals on the holographic properties of these layers.

Holographic recording in acrylamide photopolymers: thickness limitations.

Holographic recording in thick photopolymer layers is important for application in holographic data storage, volume holographic filters, and correlators. Here, we studied the characteristics of acrylamide-based photopolymer layers ranging in thickness from 250 microm to 1 mm. For each thickness, samples with three different values of absorbance were studied.