OPTICAL RANGING IN ENDOSCOPY: TOWARDS QUANTITATIVE IMAGING

Nowadays endoscopic analysis is limited to a direct and qualitative view of internal anatomy. On the other hand, the measurement of the actual size of anatomical objects could be a powerful instrument both in research and in clinical survey. For instance, an important application could be monitoring lesion size, both during diagnosis and in follow-up. The foremost obstacle to quantitative imaging is the incapability of measuring the distance between the endoscopic probe and the anatomical object under examination, since the dimension of the object in the image depends on that distance. This problem has not been solved yet in a satisfactory way. In this Chapter we describe our work to address this problem by means of an optical measurement of the distance between the endoscope distal tip and the anatomical wall. We make use of Fiber Optics Low Coherence Interferometry to realize an absolute distance sensor compatible with endoscope technology. The result is a system integrating a clinical endoscope and an optical distance sensor, equipped with a software that allows an user to acquire an endoscopic image, select a region of interest, and obtain its quantitative measure.