X-RAY: THE EMERGING ALTERNATIVE TO GAMMA IRRADIATION

When radiation is used to sterilize medical devices, it is generally by gamma irradiation. Gamma is an irradiation technology based on a radioactive Cobalt-60 source. In 2015, about 440 MCi of Cobalt-60 was in operation worldwide, half of which is located in the US. This installed activity doubles every 15 years to support the growth in the disposable medical device supply. Although very reliable and widely adopted by the industry, gamma presents challenges in terms of supply, transport, waste disposal and security. Furthermore, in the present international security context, there is growing international pressure to reduce the world’s dependence on high activity sources. Electron beam is an attractive alternative to gamma technology, but due to its limited penetration properties, substitution is not possible for all products and packaging. In most cases, X-ray is an ideal alternative to gamma since the flux of photons of both technologies have similar properties. The main advantage of X-ray systems is that they are powered by electricity, a source of energy that will remain widely available in the very long term and increasingly made of renewable energies. In theory, switching products from gamma to X-ray is very easy and would reduce the industry’s dependence on Co-60 sources. But practically, many barriers force manufacturers to keep using Co-60 sources. The main reasons are the high cost required to revalidate products from gamma to X-ray, the “non-availability” of X-ray irradiation capacity and the ease to expand capacity of existing Co-60 facilities. Without any change in Cobalt-60 supply or in regulations, it is expected that use of Cobalt-60 with pursue its growth and alternative technologies will be adopted at a very slow pace. Besides regulation changes, there are several ways to encourage capacity shift from gamma to X-ray. Potential initiatives include financial support from authorities to build new X-ray facilities and financial support to revalidate target products to allow a shift in capacity from gamma to X-ray.