Time-Resolved Reflectance Spectroscopy in Turbid Tissues

Steven Jacques

Research output: Contribution to journalArticle

116 Citations (Scopus)

Abstract

Monte Carlo simulations illustrate how various absorption μa and scattering μs coefficients influence time-dependent reflectance R(t) from a semi-infinite homogeneous turbid tissue following an impulse of narrow-beam irradiation. The tissue absorption coefficient μa in cm-1 can be obtained from measurements of R(t) after the first 20-200 ps (depends on μs) following an impulse by the expression: μa = −(n/c) d In [R(t)]/dt - 3n/2ct where n is the tissue-refractive index and c is the in vacuo speed of light. Early data in the first 20–200 ps do not conform to this expression or to diffusion theory. Monte Carlo simulations allow study of the early R(t) behavior. The volume of tissue involved in a measurement is specified by a volume radius r that approximately equals (6Dtc(c/n)1/2 where t is the time of measurement and D is the optical diffusion constant D = (3μs(1 - g))−1. At 50 ps and typical values of μs = 100 cm-1 and anisotropy equal to 0.9, r equals 5 mm. The upper limit for measurable μa values is limited by how quickly the reflectance signal is attenuated, and is estimated for current streak camera technology to be μa ≤ 21 cm-1, assuming several measurements are taken over a dynamic range of two orders of magnitude within a 10 ps period.

Original languageEnglish (US)
Pages (from-to)1155-1161
Number of pages7
JournalIEEE Transactions on Biomedical Engineering
Volume36
Issue number12
DOIs
StatePublished - 1989
Externally publishedYes

Fingerprint

Spectroscopy
Tissue
Light velocity
Streak cameras
Refractive index
Anisotropy
Irradiation
Scattering
Monte Carlo simulation

ASJC Scopus subject areas

  • Biomedical Engineering

Cite this

Time-Resolved Reflectance Spectroscopy in Turbid Tissues. / Jacques, Steven.

In: IEEE Transactions on Biomedical Engineering, Vol. 36, No. 12, 1989, p. 1155-1161.

Research output: Contribution to journalArticle

@article{3f56ad1efdb8438e98523f1621d5b479,
title = "Time-Resolved Reflectance Spectroscopy in Turbid Tissues",
abstract = "Monte Carlo simulations illustrate how various absorption μa and scattering μs coefficients influence time-dependent reflectance R(t) from a semi-infinite homogeneous turbid tissue following an impulse of narrow-beam irradiation. The tissue absorption coefficient μa in cm-1 can be obtained from measurements of R(t) after the first 20-200 ps (depends on μs) following an impulse by the expression: μa = −(n/c) d In [R(t)]/dt - 3n/2ct where n is the tissue-refractive index and c is the in vacuo speed of light. Early data in the first 20–200 ps do not conform to this expression or to diffusion theory. Monte Carlo simulations allow study of the early R(t) behavior. The volume of tissue involved in a measurement is specified by a volume radius r that approximately equals (6Dtc(c/n)1/2 where t is the time of measurement and D is the optical diffusion constant D = (3μs(1 - g))−1. At 50 ps and typical values of μs = 100 cm-1 and anisotropy equal to 0.9, r equals 5 mm. The upper limit for measurable μa values is limited by how quickly the reflectance signal is attenuated, and is estimated for current streak camera technology to be μa ≤ 21 cm-1, assuming several measurements are taken over a dynamic range of two orders of magnitude within a 10 ps period.",
author = "Steven Jacques",
year = "1989",
doi = "10.1109/10.42109",
language = "English (US)",
volume = "36",
pages = "1155--1161",
journal = "IEEE Transactions on Biomedical Engineering",
issn = "0018-9294",
publisher = "IEEE Computer Society",
number = "12",

}

TY - JOUR

T1 - Time-Resolved Reflectance Spectroscopy in Turbid Tissues

AU - Jacques, Steven

PY - 1989

Y1 - 1989

N2 - Monte Carlo simulations illustrate how various absorption μa and scattering μs coefficients influence time-dependent reflectance R(t) from a semi-infinite homogeneous turbid tissue following an impulse of narrow-beam irradiation. The tissue absorption coefficient μa in cm-1 can be obtained from measurements of R(t) after the first 20-200 ps (depends on μs) following an impulse by the expression: μa = −(n/c) d In [R(t)]/dt - 3n/2ct where n is the tissue-refractive index and c is the in vacuo speed of light. Early data in the first 20–200 ps do not conform to this expression or to diffusion theory. Monte Carlo simulations allow study of the early R(t) behavior. The volume of tissue involved in a measurement is specified by a volume radius r that approximately equals (6Dtc(c/n)1/2 where t is the time of measurement and D is the optical diffusion constant D = (3μs(1 - g))−1. At 50 ps and typical values of μs = 100 cm-1 and anisotropy equal to 0.9, r equals 5 mm. The upper limit for measurable μa values is limited by how quickly the reflectance signal is attenuated, and is estimated for current streak camera technology to be μa ≤ 21 cm-1, assuming several measurements are taken over a dynamic range of two orders of magnitude within a 10 ps period.

AB - Monte Carlo simulations illustrate how various absorption μa and scattering μs coefficients influence time-dependent reflectance R(t) from a semi-infinite homogeneous turbid tissue following an impulse of narrow-beam irradiation. The tissue absorption coefficient μa in cm-1 can be obtained from measurements of R(t) after the first 20-200 ps (depends on μs) following an impulse by the expression: μa = −(n/c) d In [R(t)]/dt - 3n/2ct where n is the tissue-refractive index and c is the in vacuo speed of light. Early data in the first 20–200 ps do not conform to this expression or to diffusion theory. Monte Carlo simulations allow study of the early R(t) behavior. The volume of tissue involved in a measurement is specified by a volume radius r that approximately equals (6Dtc(c/n)1/2 where t is the time of measurement and D is the optical diffusion constant D = (3μs(1 - g))−1. At 50 ps and typical values of μs = 100 cm-1 and anisotropy equal to 0.9, r equals 5 mm. The upper limit for measurable μa values is limited by how quickly the reflectance signal is attenuated, and is estimated for current streak camera technology to be μa ≤ 21 cm-1, assuming several measurements are taken over a dynamic range of two orders of magnitude within a 10 ps period.

UR - http://www.scopus.com/inward/record.url?scp=0024814728&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0024814728&partnerID=8YFLogxK

U2 - 10.1109/10.42109

DO - 10.1109/10.42109

M3 - Article

VL - 36

SP - 1155

EP - 1161

JO - IEEE Transactions on Biomedical Engineering

JF - IEEE Transactions on Biomedical Engineering

SN - 0018-9294

IS - 12

ER -