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Title: Direct opto-acoustic in vitro measurement of the spatial distribution of laser radiation in biological media

Abstract

The problem of opto-acoustic (AO) diagnostics of light scattering and absorption in biological media is considered. The objects under study were milk, bovine and porcine liver, and bovine muscle tissue. The forward and backward schemes for recording acoustic signals were used in experiments. The spatial distribution of the light intensity was measured for each biological medium from the temporal profile of the excited OA pulse and the absorption coefficient and reduced scattering coefficient were determined. Opto-acoustic signals were excited by a 1064-nm pulsed Nd:YAG laser and a tunable Ti:sapphire laser at 779 nm. It is shown that the proposed method can be used for obtaining a priori information on a biological medium in problems of optical and AO tomography. (special issue devoted to multiple radiation scattering in random media)

Authors:
; ; ; ;  [1]
  1. International Laser Center, M. V. Lomonosov Moscow State University, Moscow (Russian Federation)
Publication Date:
OSTI Identifier:
21456921
Resource Type:
Journal Article
Resource Relation:
Journal Name: Quantum Electronics (Woodbury, N.Y.); Journal Volume: 36; Journal Issue: 12; Other Information: DOI: 10.1070/QE2006v036n12ABEH013261
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; ACOUSTIC MEASUREMENTS; CATTLE; IN VITRO; LASER RADIATION; LIGHT SCATTERING; LIVER; MILK; MUSCLES; NEODYMIUM LASERS; PHOTOACOUSTIC SPECTROSCOPY; PULSES; SAPPHIRE; SIGNALS; SPATIAL DISTRIBUTION; TOMOGRAPHY; VISIBLE RADIATION; ANIMALS; BIOLOGICAL MATERIALS; BODY; BODY FLUIDS; CORUNDUM; DIAGNOSTIC TECHNIQUES; DIGESTIVE SYSTEM; DISTRIBUTION; DOMESTIC ANIMALS; ELECTROMAGNETIC RADIATION; FOOD; GLANDS; LASERS; MAMMALS; MATERIALS; MINERALS; ORGANS; OXIDE MINERALS; RADIATIONS; RUMINANTS; SCATTERING; SOLID STATE LASERS; SPECTROSCOPY; VERTEBRATES

Citation Formats

Pelivanov, Ivan M, Belov, Sergej A, Solomatin, Vladimir S, Khokhlova, Tanya D, and Karabutov, Aleksander A. Direct opto-acoustic in vitro measurement of the spatial distribution of laser radiation in biological media. United States: N. p., 2006. Web. doi:10.1070/QE2006V036N12ABEH013261.
Pelivanov, Ivan M, Belov, Sergej A, Solomatin, Vladimir S, Khokhlova, Tanya D, & Karabutov, Aleksander A. Direct opto-acoustic in vitro measurement of the spatial distribution of laser radiation in biological media. United States. doi:10.1070/QE2006V036N12ABEH013261.
Pelivanov, Ivan M, Belov, Sergej A, Solomatin, Vladimir S, Khokhlova, Tanya D, and Karabutov, Aleksander A. Sun . "Direct opto-acoustic in vitro measurement of the spatial distribution of laser radiation in biological media". United States. doi:10.1070/QE2006V036N12ABEH013261.
@article{osti_21456921,
title = {Direct opto-acoustic in vitro measurement of the spatial distribution of laser radiation in biological media},
author = {Pelivanov, Ivan M and Belov, Sergej A and Solomatin, Vladimir S and Khokhlova, Tanya D and Karabutov, Aleksander A},
abstractNote = {The problem of opto-acoustic (AO) diagnostics of light scattering and absorption in biological media is considered. The objects under study were milk, bovine and porcine liver, and bovine muscle tissue. The forward and backward schemes for recording acoustic signals were used in experiments. The spatial distribution of the light intensity was measured for each biological medium from the temporal profile of the excited OA pulse and the absorption coefficient and reduced scattering coefficient were determined. Opto-acoustic signals were excited by a 1064-nm pulsed Nd:YAG laser and a tunable Ti:sapphire laser at 779 nm. It is shown that the proposed method can be used for obtaining a priori information on a biological medium in problems of optical and AO tomography. (special issue devoted to multiple radiation scattering in random media)},
doi = {10.1070/QE2006V036N12ABEH013261},
journal = {Quantum Electronics (Woodbury, N.Y.)},
number = 12,
volume = 36,
place = {United States},
year = {Sun Dec 31 00:00:00 EST 2006},
month = {Sun Dec 31 00:00:00 EST 2006}
}
  • A new method for measuring the local light absorption coefficient in turbid media, for example, biological tissues, is proposed. The method is based on the fact that the amplitude of the excited opto-acoustic (OA) signal is proportional to the absorbed laser power density (the product of the light absorption coefficient and the laser fluence) at the medium interface. In the first part of the paper, the influence of the laser beam diameter, the light absorption and reduced scattering coefficients on the maximal amplitude of the laser fluence at the laser beam axis in the near-surface layer of the turbid mediummore » is studied by using the Monte-Carlo simulation. The conditions are predicted under which the amplitude of the OA signal detected in a transparent medium in contact with the scattering medium should remain proportional to the light absorption coefficient of the medium under study, when the scattering coefficient in it changes more than twice. The results of the numerical simulation are used for the theoretical substantiation of the OA method being proposed. (measurement of parametrs of laser radiation)« less
  • The second part of this work describes the experimental technique of measuring the local light absorption in turbid media. The technique is based on the measurement of the amplitude of an opto-acoustic (OA) signal excited in a turbid medium under the condition of one-sided access to the object under study. An OA transducer is developed to perform the proposed measurement procedure. Experiments are conducted for the turbid media with different optical properties (light absorption and reduced scattering coefficients) and for different diameters of the incident laser beam. It is found that the laser beam diameter can be chosen so thatmore » the dependences of the measured OA signal amplitude on the light absorption coefficient coincide upon varying the reduced scattering coefficient by more than twice. The obtained numerical and experimental results demonstrate that the OA method is applicable for measuring the local light absorption coefficient in turbid media, for example, in biological tissues. (measurement of parametrs of laser radiation)« less
  • Laser opto-acoustic technique has been used to measure the absorption coefficients of IR window materials (for example NaCl, KCl, AR-coated Ge, BaF/sub 2/, CaF/sub 2/ and ZnS) on the R(20) and the P(20) (both the 00/sup 0/1reverse arrow02/sup 0/0 band and the 00/sup 0/1reverse arrow10/sup 0/0 band) lines of a CO/sub 2/ laser. In this paper the above materials under their working conditions have also been assessed.
  • The possibility of using the opto-acoustic (OA) method for monitoring high-intensity ultrasonic therapy is studied. The optical properties of raw and boiled liver samples used as the undamaged model tissue and tissue destroyed by ultrasound, respectively, are measured. Experiments are performed with samples consisting of several alternating layers of raw and boiled liver of different thickness. The position and transverse size of the thermal lesion were determined from the temporal shape of the OA signals. The results of measurements are compared with the real size and position of the thermal lesion determined from the subsequent cuts of the sample. Itmore » is shown that the OA method permits the diagnostics of variations in biological tissues upon ultrasonic therapy. (special issue devoted to multiple radiation scattering in random media)« less