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  • LPAS
  • To create such a multi-wavelength LPAS system, Gurton, along with co-authors Melvin Felton and Richard Tober of the ARL, designed a sensor known as a photoacoustic cell. (osa.org)
  • Photon
  • Photon migration studies with the TOF technique showed changes in pulse amplitude, pulse width, and arrival time of the pulse maximum as a function of changes in Intralipid concentration. (spiedigitallibrary.org)
  • sensitivity
  • A comparison of the applicability of these techniques to register changes in the scattering properties of Intralipid samples showed that OCT is the most effective method, whereas the sensitivity of the PA technique was less pronounced. (spiedigitallibrary.org)
  • And it is this fact that gives the technique its high sensitivity, because in transmission techniques the absorptance is calculated as the difference between total light impinging on the sample and the transmitted (plus reflected, plus scattered) light, with the usual problems of accuracy when one deals with small differences between large numbers, if the absorption is small. (wikipedia.org)
  • particles
  • The gold particles that adhere to a tumor make it possible to detect the tumor with the help of existing photoacoustic techniques. (phys.org)
  • The tube was in a water bath containing scattering particles Figure 2 shows a relationship between average flow velocity and the experimental photoacoustic Doppler frequency shift. (wikipedia.org)
  • light
  • That search led Matthew O'Donnell, now dean of the college of engineering at the University of Washington in Seattle, to investigate photoacoustic techniques, in which light and sound work together. (photonics.com)
  • In a typical photoacoustic setup, pulses of laser light shine on a target, which can be a photoreactive agent , a glistening nanoparticle or a natural substance such as hemoglobin. (photonics.com)
  • A photoacoustic spectrum of a sample can be recorded by measuring the sound at different wavelengths of the light. (wikipedia.org)
  • Recently, several techniques have broken the diffraction limit of light, enabling the observation of individual cellular structures, sub-cellular structures, and processes at the nanometer level, structures that were previously unresolvable by conventional microscopes due to resolutions finer than the optical diffraction limit (~250 nm in lateral direction at high optical NA). (wikipedia.org)
  • The application of the photoacoustic effect had to wait until the development of sensitive sensors and intense light sources. (wikipedia.org)
  • Independently, considering the apparent anomalous behaviour of the photoacoustic signal from a plant leaf, which could not be explained solely by the heating effect of the exciting light, led to the cognition that photosynthetic oxygen evolution is normally a major contributor to the photoacoustic signal in this case. (wikipedia.org)
  • The term photoacoustic is also widely used, and it denotes the generation of acoustic energy by light. (wikipedia.org)
  • ultraviolet
  • Still, much of the reported research and applications, utilizing the photoacoustic effect, is concerned with the near ultraviolet/visible and infrared spectral regions. (wikipedia.org)
  • Signal
  • The photoacoustic signal amplitude was captured as a function of modulated frequency and the characteristic frequency, fc, of each sample is computed. (upm.edu.my)
  • tissue
  • Intralipid is a well-known emulsion used as a tissue-simulating phantom in developing optical imaging and diagnostic techniques for medical applications. (spiedigitallibrary.org)
  • With fairly high resolution and an ability to plumb relatively large depths into tissue - especially compared to infrared imaging - photoacoustic technology is useful for a number of imaging purposes. (photonics.com)
  • Four examples of transillumination techniques used to generate contrast in a sample of tissue paper. (wikipedia.org)
  • Monte Carlo methods provide a flexible framework that has been used by different techniques to reconstruct optical properties deep within tissue. (wikipedia.org)
  • effect
  • The discovery of the photoacoustic effect dates to 1880 when Alexander Graham Bell showed that thin discs emitted sound when exposed to a beam of sunlight that was rapidly interrupted with a rotating slotted disk. (wikipedia.org)
  • The photoacoustic effect can be used to study solids, liquids and gases. (wikipedia.org)
  • Most generally, electromagnetic radiation of any kind can give rise to a photoacoustic effect. (wikipedia.org)
  • The discovery of the photoacoustic effect dates back to 1880, when Alexander Graham Bell was experimenting with long-distance sound transmission. (wikipedia.org)
  • In 1938 Mark Leonidovitch Veingerov revived the interest in the photoacoustic effect, being able to use it in order to measure very small carbon dioxide concentration in nitrogen gas (as low as 0.2% in volume). (wikipedia.org)
  • While the heating effect of the absorbed radiation was considered to be the prime cause of the photoacoustic effect, it was shown in 1978 that gas evolution resulting from a photochemical reaction can also cause a photoacoustic effect. (wikipedia.org)
  • Although much of the literature on the subject is concerned with just one mechanism, there are actually several different mechanisms that produce the photoacoustic effect. (wikipedia.org)
  • Photoacoustic Doppler effect based imaging is a promising method for blood flow measurement in capillaries. (wikipedia.org)
  • Imaging
  • Lihong V. Wang, PhD, the Gene K. Beare Distinguished Professor of Biomedical Engineering in the School of Engineering & Applied Science at Washington University in St. Louis, summarizes the state of the art in photoacoustic imaging in the March 23 issue of Science. (quantumday.com)
  • Sentinel node biopsy provides a good example of the improvement photoacoustic imaging promises over current imaging practice. (quantumday.com)
  • To determine if a new photoacoustic imaging (PAI) system successfully depicts (1) peripheral arteries and (2) microvascular circulatory changes in response to thermal stimuli. (springer.com)
  • Fabry-Perot interferometer-based photoacoustic imaging (PAI) generates volumetric, high-resolution images of the peripheral vasculature. (springer.com)
  • Specifically, these techniques primarily break the optical diffraction limit of the photoacoustic imaging system. (wikipedia.org)
  • Photoacoustic imaging works by irradiating the target with a short-pulsed laser, or alternatively an intensity-modulated laser. (wikipedia.org)
  • Biological imaging may refer to any imaging technique used in biology. (wikipedia.org)
  • laser
  • Viator's group is focused on using the technique to look for circulating melanoma cells and has tested its photoacoustic system to train nanosecond-scale laser pulses on melanoma-laden white blood cells that have been extracted from whole blood. (photonics.com)
  • Researchers at the institute have developed laser techniques for the manipulation of structures within a living cell, and applied them medically in treatment of skin conditions, stroke, and cancer, among others. (wikipedia.org)
  • method
  • John Viator, associate professor of bioengineering and dermatology at the University of Missouri in Columbia, is developing a photoacoustic flow cytometry method that can look for single cancer cells in blood samples. (photonics.com)
  • A more recent technique based on this method is Hoffmann's modulation contrast, a system found on inverted microscopes for use in cell culture. (wikipedia.org)
  • pulse
  • Most techniques use continuous or long pulse (typically of tens of microseconds) lasers but some use short pulses to down convert very high frequencies to DC in a classic pump-probe configuration with the generation. (wikipedia.org)
  • contrast
  • Moreover, photoacoustic images have much higher contrast than X-ray images because there are many highly colored molecules in the body that serve as "endogenous" contrast agents. (quantumday.com)
  • In order to improve specimen contrast or highlight certain structures in a sample, special techniques must be used. (wikipedia.org)
  • measurement
  • These techniques can be used for titanium foams analysis, though their results can not be simply compared, because they use quite different methodologies and take different measurement assumptions. (scientific.net)
  • illumination
  • In this paper, we have implemented the variable incidence angle technique of multiple angle of illumination experiment on tendon and cartilage samples whose dominant constituents are genetically different types of collagen fibers, type I and type II, respectively. (spiedigitallibrary.org)
  • Tissue
  • The techniques outlined in this manuscript were used to conduct the first demonstration of volumetric OFDI with precise correlation to tissue-based diagnosis for evaluating pulmonary pathology 24 . (jove.com)
  • This straightforward, effective technique may be extended to other tissue types to provide precise imaging to histology correlation needed to determine fine imaging features of both normal and diseased tissues. (jove.com)
  • detect
  • The use of current T1 mapping techniques enables one to overcome these drawbacks of LGE imaging, detect diffuse myocardial abnormalities, and perform quantitative analysis of the interstitial space. (thepreparedminds.com)
  • Photoacoustics directly benefits from these techniques as the excitation can be held to a tighter spot and hence detect acoustic waves to a tighter spot, ultimately improving resolution. (wikipedia.org)
  • It is a non-contact technique used to measure materials thickness, detect flaws and carry out materials characterization. (wikipedia.org)
  • advantages
  • With many advantages such as simple manufacture technique, low cost, rapid response and recovery time, and long life and stability, semiconductor metal oxides such as SnO 2 is promising for online monitoring the fault gases in power transformer [ 9 - 16 ]. (hindawi.com)
  • The simplicity of the technique and the minimal sample preparation required are significant advantages. (wikipedia.org)
  • Signal
  • Independently, considering the apparent anomalous behaviour of the photoacoustic signal from a plant leaf, which could not be explained solely by the heating effect of the exciting light, led to the cognition that photosynthetic oxygen evolution is normally a major contributor to the photoacoustic signal in this case. (wikipedia.org)
  • researchers
  • Researchers at the institute have developed laser techniques for the manipulation of structures within a living cell, and applied them medically in treatment of skin conditions, stroke, and cancer, among others. (wikipedia.org)
  • ultrasonic
  • Heat is further converted into a pressure rise via thermoelastic expansion, and the pressure rise behaves as an ultrasonic wave, the wave of which is called a "photoacoustic wave" that propagates throughout the surroundings of the target. (wikipedia.org)
  • primarily
  • Specifically, these techniques primarily break the optical diffraction limit of the photoacoustic imaging system. (wikipedia.org)
  • Measurement and recording techniques which are not primarily designed to produce images, such as electroencephalography (EEG), magnetoencephalography (MEG), electrocardiography (ECG), and others represent other technologies which produce data susceptible to representation as a parameter graph vs. time or maps which contain data about the measurement locations. (wikipedia.org)
  • conventional
  • Recently, several techniques have broken the diffraction limit of light, enabling the observation of individual cellular structures, sub-cellular structures, and processes at the nanometer level, structures that were previously unresolvable by conventional microscopes due to resolutions finer than the optical diffraction limit (~250 nm in lateral direction at high optical NA). (wikipedia.org)
  • clinical
  • Several commercial HIFU systems are now in clinical use, although laser techniques based on this groundbreaking effort have supplanted this technique. (wikipedia.org)
  • Medical imaging is the technique and process of creating visual representations of the interior of a body for clinical analysis and medical intervention, as well as visual representation of the function of some organs or tissues (physiology). (wikipedia.org)
  • radiation
  • Most generally, electromagnetic radiation of any kind can give rise to a photoacoustic effect. (wikipedia.org)
  • While the heating effect of the absorbed radiation was considered to be the prime cause of the photoacoustic effect, it was shown in 1978 that gas evolution resulting from a photochemical reaction can also cause a photoacoustic effect. (wikipedia.org)
  • Applications
  • This book describes the types of techniques now available to the polymer chemist and technician, and discusses their capabilities, limitations and applications. (chemtec.org)
  • Still, much of the reported research and applications, utilizing the photoacoustic effect, is concerned with the near ultraviolet/visible and infrared spectral regions. (wikipedia.org)
  • Many of the techniques developed for medical imaging also have scientific and industrial applications. (wikipedia.org)
  • patient's
  • The term noninvasive is used to denote a procedure where no instrument is introduced into a patient's body which is the case for most imaging techniques used. (wikipedia.org)
  • research
  • Early research into the use of lasers included the development of techniques for the manipulation of structures within a living cell. (wikipedia.org)
  • measure
  • This technique has been used to measure Haemodynamic response within the brain. (wikipedia.org)
  • In 1938 Mark Leonidovitch Veingerov revived the interest in the photoacoustic effect, being able to use it in order to measure very small carbon dioxide concentration in nitrogen gas (as low as 0.2% in volume). (wikipedia.org)
  • produce
  • Although much of the literature on the subject is concerned with just one mechanism, there are actually several different mechanisms that produce the photoacoustic effect. (wikipedia.org)
  • Medical imaging is often perceived to designate the set of techniques that noninvasively produce images of the internal aspect of the body. (wikipedia.org)
  • high
  • Most techniques use continuous or long pulse (typically of tens of microseconds) lasers but some use short pulses to down convert very high frequencies to DC in a classic pump-probe configuration with the generation. (wikipedia.org)
  • development
  • Before the development of laser tattoo removal methods, common techniques included dermabrasion, TCA (Trichloroacetic acid, an acid that removes the top layers of skin, reaching as deep as the layer in which the tattoo ink resides), salabrasion (scrubbing the skin with salt), cryosurgery and excision which is sometimes still used along with skin grafts for larger tattoos. (wikipedia.org)
  • methods
  • Fingerprinting techniques for the rapid identification of polymers and methods for the examination of polymer surfaces and polymer defects are also discussed. (chemtec.org)
  • general
  • Biophotonics has therefore become the established general term for all techniques that deal with the interaction between biological items and photons. (wikipedia.org)