Light diffuser for the photodynamic therapy of tumors in the oesophagus of a patient

DETAILED DESCRIPTION What is claimed is: 1.
A light diffuser for photodynamic therapy of a tumor in an oesophagus of a patient, said diffuser comprising (a) a tube having a front portion and a rear portion; (b) an optical fiber for feeding laser light of a specified wavelength axial into said tube through said rear portion toward said front portion; (c) composition, including quartz grains embedded therein, contained within said tube between said rear portion and said front portion, said composition having a first refractive index and said quartz grains having a second refractive index different from said first refractive index, wherein said quartz grains have a large diameter relative to said specified wavelength of the laser light, said composition having a plurality of different regions including at least a first region and a final region arranged axially, with said final region of said plurality of regions proximal to said front portion of said tube, wherein said quartz grains embedded in the composition are of different concentrations in the different regions; (d) a mirror located within said tube between said composition and said front portion opposite said optical fiber; and (e) a sleeve-shaped probe housing wherein said tube, fiber, composition and mirror are arranged coaxially such that the laser light is deflected radially outward from said probe housing.
2.
The light diffuser of claim 1, wherein the diameter of the quartz grains is approximately 40 .
mu.
m.
3.
The light diffuser of claim 1, wherein the composition in said first region is struck directly by said laser light and wherein the concentration of quartz grains in the first region is higher than the concentration of quartz grains in the plurality of regions of the composition.
4.
The light diffuser of claim 3, wherein the plurality of regions includes an intermediate region containing a low concentration of said quartz grains, said intermediate region being located between said first region and said final region, and wherein said final region has a concentration of quartz grains less than the concentration of the first region and more than the concentration of the intermediate region