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: A method and an apparatus for the substantially uniform irradiation of the entire area of cavities from the inside. The apparatus comprises a light source and a layer comprising a material having a high-scatter capability, low transmission and low absorption, wherein said layer fits well to the interior surface of a cavity. The method comprises placing an area-covering layer along rhe cavity wall of the cavity to be irradiated with a material having a high diffusive reflection capability, low transmission, and low absorption capability to obtain a lined cavity; introducing a light source onto the interior of the lined cavity; and irradiating the lined cavity so that the light entering from the area-covering layer into the cavity wall is homogeneously distributed.