Microholography applied to tissue characterization

An in-situ holographic technique, involving the use of a flexible miniaturized endoscope (diameter less than 1 mm) coupled to a CCD camera, to record the hologram, has been developed for medical applications and more particularly in-vivo biopsy. The hologram is formed, by reflection, on the tip of a multimode, multicore fiber (MCF), sampled, and then treated electronically. The image is reconstructed numerically, providing more flexibility to the holographic process. Reconstructed images show the capability of the microendoscopic system to restore 3D informations of the observed scene. Our predictions and experimental results have shown that the hope to achieve tissue observations at the cellular level is realistic. Furthermore, the different sources of noise of the experimental device were analyzed and their influence on the quality of the reconstructed image quantified. Images of simple cell models such as epithelial cells easily taken in the oral cavity, have been taken and analyzed. The possibility of using the microholographic technique for in-vivo biopsy is discussed both from theoretical considerations and experimental observations.