Near-ir light (700-900) penetrates several centimeters into tissues and passes through bony structure and fat layers. The major contribution to light absorption in this spectral region arises from hemoglobin. In response to tissue metabolism, the hemoglobin oxygenation and its spectral properties changes and the hemoglobin concentration increases. During the previous granting period, we developed frequency-domain methods that allowed us to precisely quantify tissue oxygenation changes, in conjunction with measurements at different locations on the tissue surface. High-frequency (approximately modulated light is applied to a part of the tissue using optical fibers and then collected at different locations, generally 3-4 cm from the source, after the his diffused deep into the tissue. The determination of the tissue optical properties was very fast and suggested the possibility of performing junctional studies in the brain and the muscles that were not available before. One apparent limitation of the use of the diffusive part of the light that propagates in tissues is the relatively low spatial resolution (about 1 cm). However, our research shows that if we observe changes of tissue optical parameters, then the spatial and temporal resolution can be greatly improve with respect to steady-stage measurements. In this application, we propose to develop a new detector for the study of rapid changes (1 to 10 ms time scale) of optical parameters deep (1 to 2 cm) in tissues. The new detector can localize changes occurring in a small volume (3 mm in radius). It has low noise nd relatively high bandwidth. Using this new detector we will study the dynamics of tissues, particularly the muscle and the rain in the frequency bandwidth up to 100 Hz. Our approach signals a significant advance with respect to current methodologies and this method will provide physiologists with a new tool for functional studies of the brain and other tissues.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA057032-08
Application #
6124620
Study Section
Diagnostic Imaging Study Section (DMG)
Program Officer
Menkens, Anne E
Project Start
1992-04-01
Project End
2001-11-30
Budget Start
1999-12-01
Budget End
2000-11-30
Support Year
8
Fiscal Year
2000
Total Cost
$184,334
Indirect Cost
Name
University of Illinois Urbana-Champaign
Department
Physics
Type
Schools of Engineering
DUNS #
041544081
City
Champaign
State
IL
Country
United States
Zip Code
61820
Wolf, Ursula; Toronov, Vladislav; Choi, Jee H et al. (2011) Correlation of functional and resting state connectivity of cerebral oxy-, deoxy-, and total hemoglobin concentration changes measured by near-infrared spectrophotometry. J Biomed Opt 16:087013
Fantini, Sergio; Heffer, Erica L; Pera, Vivian E et al. (2005) Spatial and spectral information in optical mammography. Technol Cancer Res Treat 4:471-82
Safonova, Larisa P; Michalos, Antonios; Wolf, Ursula et al. (2004) Age-correlated changes in cerebral hemodynamics assessed by near-infrared spectroscopy. Arch Gerontol Geriatr 39:207-25
Morren, G; Wolf, U; Lemmerling, P et al. (2004) Detection of fast neuronal signals in the motor cortex from functional near infrared spectroscopy measurements using independent component analysis. Med Biol Eng Comput 42:92-9
Toronov, Vlad; Walker, Scott; Gupta, Rajarsi et al. (2003) The roles of changes in deoxyhemoglobin concentration and regional cerebral blood volume in the fMRI BOLD signal. Neuroimage 19:1521-31
Wolf, Martin; Franceschini, Maria A; Paunescu, Lelia A et al. (2003) Absolute frequency-domain pulse oximetry of the brain: methodology and measurements. Adv Exp Med Biol 530:61-73
Wolf, Ursula; Wolf, Martin; Choi, Jee H et al. (2003) Mapping of hemodynamics on the human calf with near infrared spectroscopy and the influence of the adipose tissue thickness. Adv Exp Med Biol 510:225-30
Wolf, Martin; Wolf, Ursula; Choi, Jee H et al. (2003) Detection of the fast neuronal signal on the motor cortex using functional frequency domain near infrared spectroscopy. Adv Exp Med Biol 510:193-7
Wolf, Martin; Wolf, Ursula; Choi, Jee H et al. (2003) Fast cerebral functional signal in the 100-ms range detected in the visual cortex by frequency-domain near-infrared spectrophotometry. Psychophysiology 40:521-8
Wolf, Martin; Wolf, Ursula; Choi, Jee H et al. (2002) Functional frequency-domain near-infrared spectroscopy detects fast neuronal signal in the motor cortex. Neuroimage 17:1868-75

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