pCLE, is composed from a miniature microscope assembled in the tip of an optical fiber. This optic fiber is then inserted through the working channel of a standard endoscope, bringing the microscope at the tip of the fiber to close proximity with the tissue. The system applies a blue-light laser that after staining with fluorescein (IV 2.5 ml, 10% fluorescein, once) provides a cellular-level, in-vivo, real time images: the concept of so called "optical biopsies". The system has been used as an auxiliary tool in GI-endoscopy in recent years. This technology has been shown to be useful in identifying objective histological features and even intramucosal bacteria in different tissues.