Medical Diagnostic Tests Based on Diode Laser Measurements of Gas Isotope Ratios

We propose to develop and deliver a portable, easy to use, non-invasive instrument to detect conditions such as glucose uptake, pancreatic functioning and H. Pylori infections of the digestive tract. The instrument will determine ratios of the isotopes 12CO2/13CO2 down to ~1% in human breath using distributed feedback (DFB) diode lasers. In Phase I we will set up a working "breadboard" model and demonstrate measurement of 12CO2/13CO2 ratios on human breath using a 1.602 micrometer DFB laser that we have already commercialized. Dr. George Lambert of the Robert Wood Johnson Medical Center (Rutgers University) has agreed to compare our instrument with his present technique for 12CO2/13CO2 isotope ratio measurements using mass spectroscopy during Phase I. We will also submit a design for our final Phase II instrument. In Phase II we will build, debug, optimize, and miniaturize the instrument using our commercial InGaAs linear detector array as a spectrometer and explore measurement of other isotope ratios of medical interest using lasers of the appropriate wavelength. Dr. Ray Martinelli of David Sarnoff Research Center will consult. This program will utilize much of the diode laser technology developed under past and present Phillips Lab programs.