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Origins of Electron Beam "Ancient" History The origins of electron beam processing can be traced back to 1895, when a paper published by Wilhelm Conrad Roentgen described the production of x-rays. Within a year, an article appeared that reported on the ability of x-rays to kill bacteria. In 1948, results of experiments on 22 species of bacteria with electrons and x-rays prompted interest from medical products manufacturers. This led to the development of the first commercial irradiation sterilizer, a small VandeGraaff accelerator. The first commercial irradiation of medical devices took place in Scotland in 1955 at the Ethicon division of the Johnson & Johnson facility, where catgut sutures were sterilized. Ethicon determined that their sutures were breaking during surgical procedures because steam and/or heat sterilization methods caused them to become brittle. The use of irradiation sterilization eliminated the breakage, and the company parlayed the technological breakthrough into a mass conversion of market share. Ethicon's suture market share grew from 5% in 1955 to more than 90% by the early 1970's. Early Designs Early accelerator systems provided poor penetration due to the low energies which the equipment produced. Those accelerators produced only a 2 MeV beam which could barely penetrate the suture material packages irradiated at Ethicon. These "ancestral" machines were also very difficult to control and were unreliable because no specific industry base was established for their use - the same machines used for medical products were also used in research laboratories. Thus, original hopes that electron beam technology could be commercialized were short-lived. The irradiation market was taken over by Cobalt-60 (gamma) equipment which did not share in the early technological shortcomings of electron beam. E-Beam Equipment Today During the 1970's, several companies, including Varian Associates, Phillips, and Siemens, took a new look at the application of x-ray technology for radiographic and oncology therapy equipment. Their involvement in the improvement of durability and reliability of accelerated electron technology raised performance parameters to a new level. Today, healthcare manufacturers can benefit from such improvements as:
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