EVIS EXERA II is equipped with a PDD (photodynamic diagnosis) function to enhance visualisation of the bladder. When a special drug (HEXVIX) is administered to the patient and the dedicated scope is used, the PDD function produces heightened contrast between the fluorescent neoplastic areas and the surrounding benign tissue for easy and effective visualisation.
How does it work?
When a photosensitive marker has been introduced transurethrally into the bladder, the inner surface of the bladder absorbs the drug over a period of 90–120 minutes and converts it into an endogenous pigment called protoporphyrin IX. This pigment is then selectively deposited in a tumour and, under blue excitation light, will emit red fluorescence. Nevertheless, in this condition, good contrast of the red fluorescence against the blue background cannot be obtained because the red fluorescence is too weak as compared with the blue light. To emphasise this fluorescence, a yellow filter exclusively designed for PDD is built into the scope. As a result, the red fluorescence can be observed with good contrast.
