Nirs device with optical wavelength and path length correction

A near infrared spectrometer for sensing tissue oxygen measurements in body tissue, comprising:

• a plurality of light sources configured to emit broadband, near infrared measurement light into body tissue;
• at least one broadband photodetector configured for sensing at least a portion of the measurement light reflected back from the body tissue;
• at least one temperature sensor configured for sensing a temperature of the light sources;
• a light attenuation model configured for modeling light attenuations within the body tissue based at least in part on the temperature sensed by the temperature sensor;
• a processor configured for estimating at least one tissue chromophore concentration within the body tissue by comparing attenuations of the sensed measurement light reflected back from the body tissue to modeled light attenuations from the light attenuation model;
• and
• wherein the processor is configured to sum the attenuations of the light in tissue at a plurality of wavelength increments, the wavelength increments being smaller than a spectral width of each light source and a responsivity of the at least one broadband photodetector.

A method for determining one or more tissue oxygen measurements in body tissue, the method comprising:

• coupling a spectrometer to a tissue of interest, the spectrometer including a plurality of light sources configured to emit broadband, near infrared measurement light into the body tissue and at least one broadband photodetector configured for sensing at least a portion of the measurement light reflected back from the body tissue;
• measuring the attenuation of the measurement light reflected back from the body tissue;
• predicting light attenuation within the body tissue using a light attenuation model, wherein the light attenuation model is configured to sum the predicted attenuations of light in tissue at a plurality of wavelength increments, the wavelength increments being smaller than a spectral width of each light source and a responsivity of the at least one broadband photodetector;
• and
• estimating at least one tissue chromophore concentration within the body tissue by comparing the attenuation of the measurement light reflected back from the body tissue to the predicted light attenuation.