Crossfire process

In the Crossfire process, a GUR 1050 rod is irradiated to 75kGy in air. The rod is then annealed at 130°C for 8 hours to eliminate free radicals. The outer surface of the rod is machined away, and components are machined from the rod. Components are packaged in nitrogen and gamma irradiated to 30kGy (N2A ac). The total radiation dose is lOSkGy. Crossfire acetabular inserts were clinically introduced in late 1998 for use in the hip Crossfire was not used for knee components. 

In the Crossfire process, extruded rod bar stock is irradiated with a nominal dose of 75kGy and then annealed at 130°C [10]. Acetabular components are then machined from the bar stock, barrier packaged in nitrogen, and then gamma sterilized with a nominal dose of 30kGy. Consequently, components that have been through the Crossfire process have received a total dose of 105 kGy. 

Subsequently, Dr. Wang asked Dr. Yau to empirically determine the best combination of cycles and radiation dose. Dr. Wang initially concentrated on the sequential material for the knee. Dr. Dumbleton s interest was in the sequential material for the hip because he hoped to replace Crossfire. Drs. Dumbleton, Wang, and Yau discussed having a lower radiation dose for the knee material than for the hip, but it turned out that the same process could be used—three sequential doses of 30kGy for a cumulative total of 90kGY—with annealing after each cycle and gas plasma sterilization [36, 37]. 

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