Design and implementation of dynamic near-infrared optical tomographic imaging instrumentation for simultaneous dual-breast measurements

Abstract

Dynamic near-infrared optical tomographic measurement instrumentation capable of simultaneous bilateral breast imaging, having a capability of four source wavelengths and 32 source-detector fibers for each breast, is described. The system records dynamic optical data simultaneously from both breasts, while verifying proper optical fiber contact with the tissue through implementation of automatic schemes for evaluating data integrity. Factors influencing system complexity and performance are discussed, and experimental measurements are provided to demonstrate the repeatability of the instrumentation. Considerations in experimental design are presented, as well as techniques for avoiding undesirable measurement artifacts, given the high sensitivity and dynamic range (1:10(9)) of the system. We present exemplary clinical results comparing the measured physiologic response of a healthy individual and of a subject with breast cancer to a Valsalva maneuver.

Systems and Strategies for Accessing the Information Content of fNIRS Imaging in Support of Noninvasive BCI Applications

“…Because of the strong dependence of signal quality on optode separation, the quality of data across the sensor array can vary greatly. This presents the need for preprocessing schemes wherein channels having poor signal quality can be excluded from subsequent analysis [7,8].…”

“…The latter arrangement allows for parallel sampling of the entire sensor array (currently up to 128 sensors) at speeds of 70-140 Hz, depending on type of signal handling circuitry. Measurements are performed using frequency-encoding techniques with homodyne detection in the audio-frequency range to allow for separate detection of light intensities from multiple illuminating wavelengths [6][7][8].…”

“…Tomography studies typically are conducted using a time-multiplexed, multi-site illumination approach wherein the full array is read for each illuminating site [1,3,4,[6][7][8]. Currently feasible are illumination/sensing approaches that support sampling from four arrays in parallel, each supporting a 32S × 32D array and up to six wavelengths (4,096 illumination-detection pairs per wavelength per image frame).…”

Optical Imaging of Breast Cancer Using Hemodynamic Changes Induced by Valsalva Maneuver

“…A possible approach for improving breast cancer detection by DOI uses differences in the hemodynamic response to changes in intrathoracic pressure between malignant and normal breast tissue. The feasibility of this concept has been shown in studies of a few patients [20,21]. The aim of our study was to verify these initial observations in a prospective patient population and to test whether DOI using Valsalva maneuver can help in detecting breast cancer and differentiating between malignant and benign breast lesions.…”

Near‐infrared imaging of breast cancer using optical contrast agents

“…To adjust for different breast sizes the fibers were positioned in the cup to ensure direct coupling between the endings of the fibers and the skin. A detail description of the system is given in [91]. The system is equipped with two wavelengths at 760 nm and 830 nm.…”