We propose to explore the feasibility of using frequency-domain methods to obtain near-infrared optical images of thick tissues. The ability to image the interior of the human body arguably constitutes the single major advance in medicine during the last century. In addition to anatomical features, it is desirable to obtain information about metabolism within various tissues. The use of near-infrared radiation has been proposed as an attractive, alternative to obtain information about the oxygenation state of tissues due to the difference in optical spectra of the oxy- and deoxy- form of hemoglobin in this spectral region. Near-infrared radiation penetrates more than 10 cm in various tissues including the brain, breast and muscles. In the optical sense, image formation is impossible because scattering produces incoherent radiation after penetrating a few millimeters into the tissue. In tissues, light undergoes a diffusive process and the transmitted intensity arises from an average of a large number of different optical paths. Different light paths can be sorted by measuring the time of flight of a short light pulse. The idea is that the """"""""early photons"""""""" correspond to the shorter paths. Our approach uses the equivalent process in the frequency-domain, i.e., the propagation of high frequency amplitude modulated light. We realize that, in the frequency- domain, propagation of the amplitude modulated intensity wave in a highly scattering medium is analogous with wave optics. In this respect, an object immersed in the medium produces deformation of the propagating wavefront of the amplitude modulated wave and the result is relatively easy to detect and analyze. This wavefront perturbation results in an easy identification of absorbing and scattering objects such as blood vessels or bone. Furthermore, frequency-domain techniques are particularly suitable for array detectors; the most promising technology for real-time imaging. We are assembling a CCD camera system which, in conjunction with a high frequency modulated laser source and a computer for data processing and display, can produce real-time images of the interior of the body. In particular, we propose to focus on: i) a systematic study of the modalities of light propagation in tissues in the framework of diffusional wave optics; ii) the design and construction of the CCD camera system with particular emphasis on the modulation and synchronization capability of these devices; and iii) the development of ancillary computer algorithms to display in real-time the wavefront of the amplitude modulated wave after traversing the tissue, i.e., display the value of the amplitude and phase at every pixel of the projection image. Instead, the application of the optical imaging technique to specific medical areas is outside the goal of this proposal. After the three year period of this grant we should be able to assess the capabilities of the frequency-domain optical imaging technique in terms of spatial resolution, contrast, penetration, sensitivity and real-time response of the CCD camera apparatus.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA057032-02
Application #
3201457
Study Section
Diagnostic Radiology Study Section (RNM)
Project Start
1992-04-01
Project End
1995-03-31
Budget Start
1993-04-01
Budget End
1994-03-31
Support Year
2
Fiscal Year
1993
Total Cost
Indirect Cost
Name
University of Illinois Urbana-Champaign
Department
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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