Abstract: A system and method for optical lymph node mapping. The system is useful for guiding sentinel lymph node biopsy surgeries. A contrast agent that includes a fluorescent dye is injected near the site of a malignancy. The contrast agent drains into the lymphatic system, collecting in a sentinel node or nodes. The system utilizes one or more low-power continuous-wave lasers or light-emitting diodes modulated with a digital code sequence to probe the tissue suspected of containing the sentinel node. When the light is incident near the sentinel node, it will excite fluorescence from the dye. A portion of the scattered fluorescent light is captured with one or more photo-detectors. A correlation of the photo-detector signal and the digital code sequence is calculated to produce an estimate of the distribution of flight times for photons traveling from a given source to a given detector.

Abstract: A system and method for measuring photons utilizing a low-power light source modulated with a code sequence to interrogate a sample of interest. Preferably a portion of the scattered light from the sample is detected by a photo-detector. A correlation of the photo-detector signal and the code sequence produces an estimate of the distribution of flight times for photons traveling from the source to the detector.

Abstract: A system and method for measuring fluorescence lifetimes utilizing a light source modulated with a code sequence to interrogate a sample of interest. The system is useful for studying the interaction of chemicals, biomolecules, and other substances. The system utilizes a low-power continuous-wave laser or light-emitting diode modulated with a digital code sequence to interrogate a sample of interest. A portion of the fluorescence light from the sample is captured with a photo-detector. A correlation of the photo-detector signal and the digital code sequence is calculated to produce an estimate of the time-response of the system. The fluorescence lifetime is extrapolated from the correlation data. The fluorescence lifetime is used as an indicator of chemical binding and chemical environment.