Application of spectral derivative data in spectral near infrared tomography

The use of the spectral derivative method in Near Infrared optical spectroscopy and tomographic imaging is presented, whereby instead of using discrete measurements around several wavelengths, the difference between nearest neighboring spectral measurements is used. The proposed technique is shown to be insensitive to the unknown tissue and fiber contact coupling coefficients providing substantially increased accuracy as compared to more conventional techniques. The self-calibrating nature of the spectral derivative techniques increases its robustness in clinical applications, as is demonstrated based on simulated results.