Dariusz Jakubowski

Near-infrared diffuse optical spectroscopy and, diffuse optical imaging show promise as noninvasive clinical techniques for breast cancer screening and diagnosis. Since NIR methods are based on optical contrast between healthy and diseased tissue, it is essential to characterize the sources of endogenous contrast in normal subjects. We report intra- and inter-subject variation and bilateral asymmetry of the optical and physiological parameters of 31 women using a seven-wavelength NIR frequency-domain photon migration instrument. Wavelength-dependent absorption and reduced scattering parameters were measured in four major quadrants and the areolar regions of left and right breasts. These values were used to determine tissue concentrations of oxy- and deoxy- hemoglobin, lipid content, water concentration, and tissue "scatter power." Mean total hemoglobin for premenopausal women is approximately two-fold higher than for postmenopausal subjects at all positions. POST women have approximately 50% higher lipid content than PRE at all positions. Water concentration on average is 1.8-fold higher for PRE subjects than POST. These differences are most pronounced when comparing the areolar complex to the other regions of the breast. In premenopausal women, the areolar regions have 40 to 45% increased total hemoglobin concentration, 20 to 25% lower lipid content, and 30 to 60% higher scatter power versus the quadrants. Small-scale changes in optical properties are negligible compared to large-scale variations over all quadrants, where the intrinsic spatial heterogeneity of healthy breast tissue is 20 to 40% for μa and 5 to 12% for μs′. Although no consistent right-left differences are observed in the study population, relative differences between symmetric positions ranged from 18 to 30% for THC, 10 to 40% for adipose, 10 to 25% for water, and 4 to 9% for scattering within an individual. © 2004 Society of Photo-Optical Instrumentation Engineers.

Near-infrared diffuse optical spectroscopy and imaging may enhance existing technologies for breast cancer screening, diagnosis, and treatment. NIR techniques are based on quantitative measurements of functional contrast between healthy and diseased tissue. In this study we measured the spectral dependence of tissue absorption and reduced scattering in the breasts of 30 healthy women and one woman with a fibroadenoma using a seven-wavelength frequency-domain photon migration probe. Subjects included pre- and postmenopausal women between the ages of 18 and 64. Multi-spectral measurements were used along with a four-component fit to determine the concentrations of de-oxy and oxyhemoglobin, water and lipids in breast. The scattering spectral shape was also quantified. Our measurements demonstrate that the measured concentrations of NIR analytes correlate well with known breast physiology. Although the tissue scattering at a single wavelength was found to have little value as a functional parameter, the dependence of the scattering on wavelength provided key insights into breast composition and physiology. Lipids and scattering spectra in the breast were found to increase and decrease, respectively, with increasing body mass index. Simple calculations are also provided to demonstrate potential penalties from ignoring the contributions of water and lipids in breast measurements. Finally, water is shown to be a possible indicator for detecting a fibroadenoma, whereas the hemoglobin saturation was found to be a poor indicator. Multi-spectral measurements, compared to measurements restricted to one or two wavelengths, provide additional information that may be useful in managing breast disease. © 2002 Society of Photo-Optical Instrumentation Engineers.

Rationale and Objectives. Near-infrared diffuse optical spectroscopy and imaging may enhance existing technologies for breast cancer screening, diagnosis, and treatment. NIR techniques are based on sensitive, quantitative measurements of functional contrast between healthy and diseased tissue. In this study, the authors quantified the origins of this contrast in healthy breasts. Materials and Methods. A seven-wavelength frequency-domain photon migration probe was used to perform noninvasive NIR measurements in the breasts of 28 healthy women, both pre- and postmenopausal, aged 18-64 years. A diffusive model of light transport quantified oxygenated and deoxygenated hemoglobin, water, and lipid by their absorption signatures. Changes in the measured light-scattering spectra were quantified by means of a "scatter power" parameter. Results. Substantial quantitative differences were observed in both absorption and scattering spectra of breast as a function of subject age. These physiologic changes were consistent with long-term hormone-dependent transformations that occur in breast. Instrument response was not adversely affected by subject age or menopausal status. Conclusion. These measurements provide new insight into endogenous optical absorption and scattering contrast mechanisms and have important implications for the development of optical mammography. NIR spectroscopy yields quantitative functional information that cannot be obtained with other noninvasive radiologic techniques.

A technique for measuring broadband near-infrared absorption spectra of turbid media that uses a combination of frequency-domain and steady-state reflectance methods is presented. Most of the wavelength coverage is provided by a white-light SS measurement, whereas the FD data are acquired at a few selected wavelengths. Coefficients of absorption and reduced scattering derived from the FD data are used to calibrate the intensity of the SS measurements and to estimate μ‘s at all wavelengths in the spectral window of interest. After these steps are performed, one can determine ma by comparing the SS reflectance values with the predictions of diffusion theory, wavelength by wavelength. Absorption spectra of a turbid phantom and of human breast tissue in vivo, derived with the combined SSFD technique, agree well with expected reference values. All measurements can be performed at a single source-detector separation distance, reducing the variations in sampling volume that exist in multidistance methods. The technique uses relatively inexpensive light sources and detectors and is easily implemented on an existing multiwavelength FD system. © 2000 Optical Society of America.