A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry

Imaging biological processes in mammalian tissues will be facilitated by fluorescent probes with excitation and emission bands within the near-infrared optical window of high transparency. Here we report a phytochrome-based near-infrared fluorescent protein (iRFP) with excitation and emission maxima at 690 nm and 713 nm, respectively. iRFP does not require an exogenous supply of the chromophore biliverdin and has higher effective brightness, intracellular stability and photostability than earlier phytochrome-derived fluorescent probes. Compared with far-red GFP-like proteins, iRFP has a substantially higher signal-to-background ratio in a mouse model due to its infrared-shifted spectra.

Bright and stable near-infrared fluorescent protein for in vivo imaging

Fundamentals of statistical signal processing: Estimation theory: by Steven M. KAY; Prentice Hall signal processing series; Prentice Hall; Englewood Cliffs, NJ, USA; 1993; xii + 595 pp.; $65; ISBN: 0-13-345711-7

Effects of lipophilic emulsifiers on the oral administration of lovastatin from nanostructured lipid carriers: Physicochemical characterization and pharmacokinetics

In cancer surgery, intra-operative assessment of the tumor-free margin, which is critical for the prognosis of the patient, relies on the visual appearance and palpation of the tumor. Optical imaging techniques provide real-time visualization of the tumor, warranting intra-operative image-guided surgery. Within this field, imaging in the near-infrared light spectrum offers two essential advantages: increased tissue penetration of light and an increased signal-to-background-ratio of contrast agents. In this article, we review the various techniques, contrast agents, and camera systems that are currently used for image-guided surgery. Furthermore, we provide an overview of the wide range of molecular contrast agents targeting specific hallmarks of cancer and we describe perspectives on its future use in cancer surgery.

/pdf/optical-image-guided-surgery-where-do-we-stand-2nqdecln30.pdf

Optical Image-guided Surgery—Where Do We Stand?

A new method is described for obtaining a 3-D reconstruction of a bioluminescent light source distribution inside a living animal subject, from multispectral images of the surface light emission acquired on charge-coupled device (CCD) camera. The method uses the 3-D surface topography of the animal, which is obtained from a structured light illumination technique. The forward model of photon transport is based on the diffusion approximation in homogeneous tissue with a local planar boundary approximation for each mesh element, allowing rapid calculation of the forward Green's function kernel. Absorption and scattering properties of tissue are measured a priori as input to the algorithm. By using multispectral images, 3-D reconstructions of luminescent sources can be derived from images acquired from only a single view. As a demonstration, the reconstruction technique is applied to determine the location and brightness of a source embedded in a homogeneous phantom subject in the shape of a mouse. The technique is then evaluated with real mouse models in which calibrated sources are implanted at known locations within living tissue. Finally, reconstructions are demonstrated in a PC3M-luc (prostate tumor line) metastatic tumor model in nude mice.

https://umanitoba.ca/faculties/health_sciences/medicine/units/cacs/sam/media/Xenogen_DLIT_2007.pdf

Three-dimensional reconstruction of in vivo bioluminescent sources based on multispectral imaging.

Spectral unmixing is a useful technique in fluorescence imaging for reducing the effects of native tissue autofluorescence and separating multiple fluorescence probes. While spectral unmixing methods are well established in fluorescence microscopy, they typically rely on precharacterized in-vitro spectra for each fluorophore. However, there are unique challenges for in-vivo applications, since the tissue absorption and scattering can have a significant impact on the measured spectrum of the fluorophore, and therefore make the in-vivo spectra substantially different to that of in vitro. In this work, we introduce a spectral unmixing algorithm tailored for in-vivo optical imaging that does not rely on precharacterized spectral libraries. It is derived from a multivariate curve resolution (MCR) method, which has been widely used in studies of chemometrics and gene expression. Given multispectral images and a few straightforward constraints such as non-negativity, the algorithm automatically finds the signal distribution and the pure spectrum of each component. Signal distribution maps help separate autofluorescence from other probes in the raw images and hence provide better quantification and localization for each probe. The algorithm is demonstrated with an extensive set of in-vivo experiments using near-infrared dyes and quantum dots in both epi-illumination and transillumination geometries.

https://www.spiedigitallibrary.org/journals/Journal-of-Biomedical-Optics/volume-14/issue-06/064011/In-vivo-fluorescence-imaging-with-a-multivariate-curve-resolution-spectral/10.1117/1.3258838.pdf

In-vivo fluorescence imaging with a multivariate curve resolution spectral unmixing technique

The invention relates to topographic construction that combines photographic and structured light information. The dual modality construction acquires structured light information for an object and photographic images from multiple views about the object. Topographic construction then processes the structured light information and photographic data in the multiple images to generate a surface representation of the object in each modality. The photographic and structured light surface representations are then combined to output a dual modality surface topography.

Surface construction using combined photographic and structured light information

Described herein are systems and methods for obtaining a three-dimensional (3D) representation of the distribution of fluorescent probes inside a sample, such as a mammal. Using a) fluorescent light emission data from one or more images, b) a surface representation of the mammal, and c) computer-implemented photon propagation models, the systems and methods produce a 3D representation of the fluorescent probe distribution in the mammal. The distribution may indicate—in 3D—the location, size, and/or brightness or concentration of one or more fluorescent probes in the mammal.

Fluorescent light tomography

Described herein are systems and methods for spectral unmixing of in vivo light data. The spectral unmixing separates image data according to spectra from multiple internal light sources in an effort to isolate one or more spectrum of interest. The spectral unmixing obtains images with a combination of different and known excitation and emission limits. The spectral unmixing then uses an iterative solution process to separate spectra for the multiple fluorescent light sources, and provides a spectrum and/or a spatial distribution map for at least one of the internal light sources.

Heng Xu

Papers

Three-dimensional reconstruction of in vivo bioluminescent sources based on multispectral imaging.

In-vivo fluorescence imaging with a multivariate curve resolution spectral unmixing technique

Surface construction using combined photographic and structured light information

Fluorescent light tomography

Spectral unmixing for in-vivo imaging