Introduction

In 1956, Johnson & Johnson developed the first commercial application of electron beam sterilization processing for medical devices. The early high hopes for commercializing electron beam technology were short-lived due to the poor reliability of the major components of these early systems, and the radiation sterilization opportunity was soon replaced by Cobalt-60 (gamma) irradiators.

With the advent of national laboratories devoted to high energy physics research, a major effort was put into improving the reliability and performance of critical accelerator components. By the 1970's, industrial involvement in the development of radiographic and oncology machines further enhanced the durability and reliability of electron accelerators. This improvement of component performance, along with the integration of computerized controls, encouraged the industry to re-evaluate electron beam technology, which led to today's keen interest in electron beam sterilization systems.

What is driving the interest in e-beam if gamma and ethylene oxide are effective and in adequate supply? Time. Electron beam processing has the shortest process cycle of any currently recognized sterilization method. In electron beam processing, products are scanned for seconds, with the bulk of the processing time consumed in transporting products into and out of the radiation shielding. Overall process time, including transport time, is 5 to 7 minutes. Using established and recognized dosimetric release procedures, the product can be released from quarantine within 30 minutes.

Another processing time reduction results from electron beam's ability to change over from one lot to another quickly, thus saving additional time. Products are sterilized as they become available from the upstream production cycle, and no dose groupings or product staging is necessary. For example, electron beam can transition from a product requiring a 25 kGy dose to a different product requiring an 18 kGy dose in the same 5 to 7 minute time frame.

As the sterilization process is reduced from weeks or days to hours, inventory working capital requirements are reduced proportionately. The opportunity for shortening the manufacturing cycle with in-line sterilization continues to attract worldwide attention to electron beam processing.