As one of the most commonly-used materials in the radiotherapy of head tumors, U-face-mask is fixed on a motherboard by means of smash-pressing. It models and fixes conveniently, and the resulting shapes are attractive, so it is one of the first choices of physicians. As the mask is greatly stretched in the process of molding, the material tends to become thinner, and the fixing effect will be affected to some extent. Materials with a small aperture and a small percentage of mesh are generally used.
