A novel ultralow-illumination endoscope system

Endoscopic surgery has become an accepted major type of minimally invasive surgery. However, complications arising from heat generated by sources of endoscopic illumination can include surgical fire or burns, and intense illumination during ob-gyn/fetoscopic surgery might damage fetal ocular development. Fiber-optic bundles for illumination within the endoscope essentially double the outer diameter of the endoscope, which is a major obstacle to miniaturization and decreasing costs. Light cables also decrease the maneuverability of the endoscope

We developed a novel endoscope with ultralow illumination to visualize dark body cavities and investigated its feasibility in vivo. An adaptor was created to connect a conventional endoscope to an ultrahigh-sensitivity camera developed by the Japan Broadcasting Corporation (NHK) for broadcasting. The ability to visualize rabbit visceral blood vessels in vivo by the new prototype and by a current endoscope under ultralow illumination provided by a standard light source was compared. In addition, the performance of the two endoscopes was compared using only an extracorporeal flashlight without any specific light source placed within body cavities.

The new endoscope could visualize the target under ultralow illumination of approximately 100 lx. Very little could be visualized using the current endoscope, whereas the prototype generated clear images of the rabbit blood vessels under both ultralow illumination and extracorporeal illumination provided by a flashlight.

The potential for damage caused by a light source can be minimized using our new endoscope, which results in safer and less invasive procedures. Further studies are under way to develop a nonilluminated endoscope without a light cable or source and to miniaturize the camera to decrease costs and improve the maneuverability of the entire endoscope system.