Radiation Sterilization: Dose Is Dose

Abstract

In the radiation sterilization arena, the question often arises as to whether radiation resistance of microorganisms might be affected by the energy level of the radiation source and the rate of the dose delivered (kGy/time). The basis for the question is if the microbial lethality is affected by the radiation energy level and/or the rate the dose is delivered, then the ability to transfer dose among different radiation sources could be challenged. This study addressed that question by performing a microbial inactivation study using two radiation sources (gamma and electron beam [E-beam]), two microbial challenges (natural product bioburden and biological indicators), and four dose rates delivered by three energy levels (1.17 MeV [gamma], 1.33 MeV [gamma], and 10 MeV [high-energy E-beam]). Based on analysis of the data, no significant differences were seen in the rate of microbial lethality across the range of radiation energies evaluated. In summary, as long as proof exists that the specified dose is delivered, dose is dose.

Viral inactivation by light

“…In conclusion, the sterilization doses can be safely transferred between modes and sources of irradiation. As long as there is evidence that the specified dose is delivered, dose equals dose, regardless of the type of irradiation source (gamma, X-ray or electron beams) [ 92 ].…”

Radiation processing of bacterial cellulose-monolaurin wound dressing: Physicochemical effects, functional analysis, and sterilization

“…43,44 Radiation sterilization relies on ionizing radiation to inactivate microorganisms and the radiation sterilization dose (RSD) must represent a sterility assurance level of 10 À6 , which defines a probability of 1 in 1000 000 that a device is not sterile. 45 In establishing RSD, a dose substantiation method for 25 or 15 kGy as a sterilization dose to achieve a 10 À6 SAL is used. The method for 25 kGy applies to products with an average bioburden less than or equal to 1000 CFU/g, whereas the method for 15 kGy applies to products with a bioburden less than or equal to 1.5 CFU/g.…”

“…43,44 Radiation sterilization relies on ionizing radiation to inactivate microorganisms and the radiation sterilization dose (RSD) must represent a sterility assurance level of 10 −6 , which defines a probability of 1 in 1000 000 that a device is not sterile. 45…”