[6][7][8][9] Commercially available clinical and pre-clinical endomicroscopes can achieve a resolution on the order of a micrometre, have a field-of-view of several hundred μm, and are compatible with fluorophores which are excitable using 488 nm laser light.
The main clinical applications are currently in imaging of the tumour margins of the brain and gastro-intestinal tract, particularly for the diagnosis and characterisation of Barrett’s Esophagus, pancreatic cysts and colorectal lesions.
[10] Endomicroscopes achieve optical sectioning (removal of the background intensity) using the confocal principle - each image frame is assembled in a point-by-point fashion by scanning a laser spot rapidly over the tissue.
[14][15][16] They consist of a large number (up to tens of thousands) of fibre cores inside a single shared cladding, are flexible, and have diameters on the order of a millimetre.
Four endomicroscope products have been developed: The fluorescence in vivo endomicroscope - FIVE2 (OptiScan Imaging Ltd, Melbourne, Australia) developed for pre-clinical research, the neurosurgical device Convivo (Carl Zeiss Meditech AG, Jena, Germany), the Pentax ISC-1000/EC3870CIK endoscope (Pentax/Hoya, Tokyo, Japan), now withdrawn from some markets, and Cellvizio (Mauna Kea Technologies, Paris, France).
The original Pentax instrument had variable frame rate up to 1.6 fps and dynamic adjustment of working distance by the user over a depth range from surface to 250 μm.
Mauna Kea’s Cellvizio device has an external laser scanning unit and offers a selection of fibre-bundle based probes with resolution, field of view and working distance optimised for different applications.
[3] Research studies have suggested a large range of potential applications, including in the urinary tract,[5] head and neck,[25] ovaries,[26] and lungs.