Endoscope

A sterilizable endoscope of small diameter has a central coherent fibre bundle for carrying an image to a viewing means, and the fibre bundle is surrounded by light fibres. The proximate end of the endoscope is provided with a coupling means (14) for aligning the coherent optical bundle with the optical system of the viewing means and for providing an interface with light transmitting means to transmit light from a light source along the light fibres to a body cavity to be inspected. The coupling means (14) may have a diameter no bigger than the diameter of the covering of the endoscope. When the endoscope is used inside a larger endoscope or a trochar, the latter can be removed while the former remains in place. This is accomplished by removing the viewing means and sliding the larger endoscope or trochar over the other endoscope and then replacing the viewing means for further viewing within the body cavity. The device can be used for detection of cancer cells and treatment thereof by phototherapy. A dye is attached to the tissue being examined and subsequently exposed to an exciting laser light frequency. Cancer cells will emit fluorescent light which is detected and displayed on the video monitor and the same light frequency is then transmitted through the light fibres to the cell for phototherapy treatment.