Abstract: An apparatus for the isotropic irradiation of cavity walls includes in a first channel of a catheter a light conducting fiber which has a cortically shaped tip for deflecting a light beam radially outwardly through a transparent portion of the catheter and a resiliently expandable sleeve tightly disposed around the catheter and having its interior in communication by a second channel with a fluid supply for expanding the sleeve so as form a light scattering structure whose scattering characteristics are adjustable dependent on the degree of sleeve expansion.

Abstract: Apparatus for the isotropic emission and for the isotropic reception of light which includes a light conductor having a conical distal end with a scattering body mounted thereon in spaced relationship such that a cavity is formed between the light conductor end and the scattering body. The apparatus permits access to cavities such as hollow organs for internal laser phototherapy, for example.

Abstract: In a heart catheter which consists of a hose having a sonde with an electrode structure for locating pathological areas arranged at its distal end, a light transmitting fiber is movably disposed in the hose and the hose has sensors associated therewith so as to be movable together with the fiber out of the distal end of the hose for engagement with the tissue of the pathological area for positioning the distal end of the hose at a predetermined distance and location relative to the pathological area in order to provide for appropriate irradiation of the pathological area by radiation energy supplied through the light transmitting fiber.