A5029521419- Optical Imaging and Spectroscopy Techniques
- Spectroscopy Techniques in Biomedical and Chemical Research
- Photoacoustic and Ultrasonic Imaging
- Laser Design and Applications
- Infrared Thermography in Medicine
- Laser-Matter Interactions and Applications
- Solid State Laser Technologies
- Advanced Fluorescence Microscopy Techniques
- Spectroscopy and Chemometric Analyses
- Optical Coherence Tomography Applications
- Non-Invasive Vital Sign Monitoring
- Advanced Fiber Laser Technologies
- Cell Image Analysis Techniques
- Photodynamic Therapy Research Studies
- Optical Polarization and Ellipsometry
- Photoreceptor and optogenetics research
- Spectroscopy and Quantum Chemical Studies
- Nanoplatforms for cancer theranostics
- AI in cancer detection
- Spectroscopy and Laser Applications
- Esophageal Cancer Research and Treatment
- Laser-Plasma Interactions and Diagnostics
- Nanoparticle-Based Drug Delivery
- Laser-induced spectroscopy and plasma
- Ultrasound Imaging and Elastography
Boston University
2015-2025
Los Alamos National Laboratory
1996-2022
Boston Medical Center
2010-2011
University College London
2006-2011
University College Hospital
2006-2011
VA Boston Healthcare System
2006
The Royal Free Hospital
2006
Princeton University
1989
Brookhaven National Laboratory
1989
University of California System
1980
Predictions from Mie theory regarding the wavelength dependence of scattering in tissue near UV to IR are discussed and compared with experiments on phantoms. For large fiber separations it is shown that rapid, simultaneous measurements elastic scatter signal for several can yield absorption coefficient reduced coefficient. With this information, size particles be estimated, done Intralipid. Measurements made at smaller source detector support calculations, demonstrating sensitivity...
The <i>Journal of Biomedical Optics</i> (JBO) is a Gold Open Access journal that publishes peer-reviewed papers on the use novel optical systems and techniques for improved health care biomedical research.
Abstract Background and Objectives: Recently, significant progress has been made toward the development of optical, noninvasive medical diagnostics. The goal this study was to evaluate elastic scatter measurements as a tool for diagnosing bladder cancer. Study Design/Materials Methods: In vivo on 10 patients with suspected cancer were optical biopsy system (OBS) developed at Los Alamos National Laboratory. Elastic‐scatter spectra over wavelength range 250–800 nm obtained using fiber‐optic...
We present experimental results that show the spatial variations of diffuse-backscattered intensity when linearly polarized light is incident upon highly scattering media. Experiments on polystyrene-sphere and Intralipid suspensions demonstrate radial azimuthal observed pattern depend concentration, size, anisotropy factor g particles constitute medium. Measurements performed biological-cell potential this method for cell characterization.
We report on the development of a method that records spatially dependent intensity patterns polarized light is diffusely backscattered from highly scattering media. It demonstrated these can be used to differentiate turbid media, such as polystyrene-sphere and biological-cell suspensions. Our technique employs He-Ne laser (l=543nm), which focused onto surface medium. A area approximately 4x4 cm centered input point imaged through polarization-analysis optics CCD camera. One observe large...
Many methods of optical tissue diagnosis require that measurements be performed with small source-detector separations in a backscatter geometry. Monte Carlo simulations are used to demonstrate for these situations light transport depends on the exact form angular scattering probability distribution, P(theta). Simulations different forms P(theta) same value ?cos theta? result collection significantly fractions incident photons, particularly when small-numerical-aperture delivery and fibers...
The noninvasive measurement of variations in absorption that are due to changes concentrations biochemically relevant compounds tissue is important many clinical settings. One problem with such measurements the path length traveled by collected light through depends on scattering properties tissue. We demonstrate, using both Monte Carlo simulations and experimental measurements, for an appropriate separation between light-delivery light-collection fibers photons does not depend parameters...
Monte Carlo simulations and experiments in tissue phantoms were used to empirically develop an analytical model that characterizes the reflectance spectrum a turbid medium. The extracts optical properties (scattering absorption coefficients) of medium at small source-detector separations, for which diffusion approximation is not valid. accuracy inversion algorithm investigated validated. Four fiber probe configurations tested both source detector fibers tilted predetermined angle, with...
This article reports the development of an optical imaging technique, confocal light absorption and scattering spectroscopic (CLASS) microscopy, capable noninvasively determining dimensions other physical properties single subcellular organelles. CLASS microscopy combines principles light-scattering spectroscopy (LSS) with microscopy. LSS is technique that relates elastically scattered by small particles to their size, refractive index, shape. The multispectral nature enables it measure...
Spectral reflectance measurements of biological tissues have been studied for early diagnoses several pathologies such as cancer. These are often performed with a fiber optic probe in contact the tissue surface. We report study which obtained vivo from mouse thigh muscle while varying pressure probe. It is determined that variable affects local optical properties tissue. The spectra analyzed an analytical model extracts and facilitates understanding underlying physiological changes induced...
The temperature dependence of dc electric-field-induced optical second-harmonic generation has been measured for C${\mathrm{H}}_{4}$, C${\mathrm{H}}_{3}$F, C${\mathrm{H}}_{2}$${\mathrm{F}}_{2}$, CH${\mathrm{F}}_{3}$, C${\mathrm{F}}_{4}$, CCl${\mathrm{F}}_{3}$, and CBr${\mathrm{F}}_{3}$. For each molecule, experiments yield the second-order polarizability $\overline{\ensuremath{\chi}}(\ensuremath{-}2\ensuremath{\omega}; \ensuremath{\omega}, \ensuremath{\omega})$ third-order 0,...
Bacterial pathogens are one of the primary causes human morbidity worldwide. Historically, antibiotics have been highly effective against most bacterial pathogens; however, increasing resistance bacteria to a broad spectrum commonly used has become global health-care problem. Early and rapid determination susceptibility essential in many clinical settings and, sometimes, can save lives. Currently classical procedures require at least 48 h for determining susceptibility, which constitute...
Measurements of the tissue concentrations two chemotherapy agents have been made in vivo on an animal tumour model. The method used is based elastic-scattering spectroscopy (ESS) and utilizes a fibre-optic probe spectroscopic system. A broadband light source to acquire data over broad range wavelengths and, therefore, facilitate separation absorptions from various chromophores. results work include measurements time course drug as well comparison optical with high-performance liquid...
We present the first reported observation in infrared of nonlinear phase-conjugated reflection. This was achieved via degenerate four-wave mixing polycrystalline germanium. The facilitated by taking advantage counterpropagating (strong) waves internal to a pulsed CO2 laser cavity. measured effective reflectivity 2% with 10-mm interaction length. simple intracavity technique is generally applicable any material transparent at wavelength into which it inserted.
The ratio of dc electric-field-induced optical second-harmonic coefficients $R\ensuremath{\equiv}\frac{{X}_{\mathrm{yyyy}}(\ensuremath{-}2\ensuremath{\omega};0,\ensuremath{\omega},\ensuremath{\omega})}{{X}_{\mathrm{yyxx}}(\ensuremath{-}2\ensuremath{\omega};0,\ensuremath{\omega},\ensuremath{\omega})}$ has been measured for each the inert gases. results at $\ensuremath{\omega}=0.066$ a.u. (the ruby-laser frequency) are: helium, 2.97 \ifmmode\pm\else\textpm\fi{} 0.03; neon, 3.01 0.05; argon,...
Bacterial resistance to antibiotics is becoming a global health-care problem. Bacteria are involved in many diseases, and have been the most effective treatment for them. It essential treat an infection with antibiotic which infecting bacteria sensitive; otherwise, not may lead life-threatening progression of disease. Classical microbiology methods that used determination bacterial susceptibility time consuming, accounting problematic delays administration appropriate drugs....
Imaging technologies working in the spatial frequency domain are becoming increasingly popular for generating wide-field maps of optical properties, enabling rapid analysis tissue parameters. While acquisition methods have become faster and now performing real-time, processing remain slow, precluding real-time display information. We present solutions that rapidly solve inverse problem extracting properties by use advanced lookup tables (LUTs). results based on a dense, linearly sampled...
Illumination uniformity is critical for widefield optical microscopy, especially high-throughput and accurate quantitative imaging of biological specimens. While traditional Köhler illumination improves uniformity, it often fails to deliver homogeneous intensity across large fields view. Existing computational correction techniques remain inadequate a broad range applications. Here, we implement novel device that call the effective uniform color-light integration (EUCLID), quantifying...