A review on the clinical implementation of respiratory-gated radiation therapy.

The invention relates to a roller mill with two rollers, a grinding gap formed thereby and a material inlet shaft the end walls of which bear on their lower ends carrier plates with replaceable sintered metal wear parts. Each wear part is formed by a plurality of small sintered metal plates of small area which are set close against one another like a mosaic and are individually screwed onto the carrier plate so that in case of wear only those small sintered metal plates which are actually worn can be replaced simply, quickly and economically.