Verfahren zur Untersuchung eines biologischen Gewebes mit nichtionisierender Strahlung

摘要

On the basis of multiple scattering of photons in tissues, the local resolution that can be obtained through an phototomographical process is currently only 10-15mm. By way of comparison, established medical diagnostic processes can provide images of up to 1mm.The Doppler scattering of photons in areas of tissue supplied with blood leads to enlargement of the frequency spectrum of the light detected in relation to incident light, wherein the amount of enlargement depends on the average number of Doppler scattering processes per photon and consequently on the average penetration depth of the photons. Discrimination of depth can thereby be achieved by subjecting the power spectrum of the detected scattering to a high-pass filtering. Only photons whose Doppler displacement is located above the filter threshold or whose average penetration depth is above a minimal value which is predetermined by the filter threshold, contribute to the measuring signal.Optical tompography, transcranial measurement of brain function, measurement of the degree of the blood flow in deep layers of tissue.