Abstract: A device for the irradiation of internal cavities of the body includes a flexible catheter, made of a transparent material, containing a fiber optic of which the section at one end is designed to radially diffuse light coming from a source arranged at the other end. An inflatable balloon fixed to one end of the catheter surrounds the diffusing section of the fiber optic. The balloon is made of an elastomeric material that diffuses the light and is prefabricated by molding based on the shape of the cavity to be treated. The balloon presses against the cavity wall and, with the thickness of its surfaces remaining constant after inflation, the pressure needed for inflation is low and cannot damage the cavity tissues.

Abstract: A light diffusing device for the irradiation of biological tissues in photodynamic treatment includes a light guide having an unclad section at its distal tip, the unclad section being surrounded with at least one layer of diffusing substance for diffusing the light circulating in the light guide. The diffusing layer includes a prefabricated tubular piece having walls of constant thickness in which the unclad section is inserted.