Patent ID: 8417323

Claim:
An apparatus for depth-resolved measurements of properties of tissue, said apparatus comprising: a) an illumination device configured to illuminate the tissue with light; b) a collector device configured to collect light which has not been absorbed by the tissue; c) a determination device configured to determine properties of the tissue in different depths from the collected light; d) a casing, in which at least a part of the illumination device and the collector device are located, for advancing into a hollow object, wherein the illumination device and the collector device are configured to collect light depth-resolved, and wherein the determination device is configured to determine depth-resolved properties of the tissue from the light, which has been collected depth-resolved, wherein the illumination device comprises different illuminators that are arranged circularly around the collector device and are movable to change a distance between the illumination device and the collector device in order to collect light signals having different penetration lengths.