The present invention provides an apparatus and method for the internal treatment of body cavities and damaged internal vessels using irradiation. A device and method according to the invention may be used to irradiate an internal tissue surface, for example, for the treatment of an aneurysm, tissue welding, or the removal of a stenosis in a blood vessel. In one embodiment, the invention provides a device for illuminating a body surface including a shaft having a light guide, a control unit, and a light scatterer. The control unit includes a light source optically coupled to the light guide and the light scatterer is optically coupled to the light guide. The light scatterer includes a first, rear surface and a second, forward illuminating surface, and the light scatterer has a first undeployed, collapsed configuration and a second deployed configuration in which the illuminating surface has a larger caliber than in the first undeployed, collapsed configuration. In another embodiment, the invention provides an implantable device for irradiating a body surface comprising a shaft having a light source consisting of fiber optics or light emitting diodes embedded thereon. Activation and control of the energy emitted by the light source may be controlled by direct connection of wires, or remotely controlled by an external wireless remote control set.
