title: Casting of electron field defining apertures: casting with the metal mold kits.
abstract: Cerrobend alloy casts are made to define the desired electron field shapes. These custom casts are fabricated for the selected electron applicator size that has been chosen for the patient. When the cast is placed into that selected electron applicator, it will block out areas that are not to be treated. When an all metal mold assembly was used for the fabrication of these casts, the lip region of the cast which is used to accurately align the cast in the actual treatment applicator, had an irregular edge that prevented an accurate alignment of the cast. To eliminate the irregular edges on the lip region of the cast, the metal mold assembly was heated to approximately 80-85 degrees C before the molten cerrobend alloy was poured into it. The heating of the metal mold assembly helps eliminate the irregular edges on the lip region of the cast. Unfortunately it also created new flaws such as holes, dents, cracks and/or crystallization of the cast as it solidified. These flaws were controlled by cooling the metal mold assembly and the cast immediately after the pouring of the molten cerrobend alloy, evenly with water.
authors.affiliation: Department of Radiation Oncology, University of California, San Francisco 94143.
authors.forename: D
authors.initials: D
authors.lastname: Dea
authors.forename: E
authors.initials: E
authors.lastname: San Luis
mesh_terms: D000497:Alloys; D004583:Electrons; D006801:Humans; D008669:Metallurgy; D010315:Particle Accelerators; D011882:Radiotherapy, High-Energy / Q000295:instrumentation*
chemical_list: D000497:Alloys