Validating a low dose gamma irradiation process for sterilizing allografts using ISO 11137 method 2B
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Updated: Aug 14, 2026

Low-Dose Gamma Radiation Sterilization for Decellularized Tracheal Grafts
Published on: April 14, 2023
Thomas F Baker1, Chad J Ronholdt, Simon Bogdansky
1AlloSource, 6278, S. Troy Circle, Centennial, CO 80111, USA. tbaker@allosource.org
Abstract:
This paper describes the validation of an allograft sterilization method specifically designed for the processing methods used at AlloSource in Centennial, CO. The methods used for this validation followed ISO Standard 11137, Method 2B. Three hundred allografts, collected from three defined production batches were dosed using a series of five incremental doses, beginning at 1 kGy and increasing by 1 kGy until 5 kGy was achieved. Following sterilization dosing, each allograft test article was analyzed using a sterility test to identify any viable microorganisms. The number of positive sterility samples was used to calculate the verification dose (1.27 kGy), which was then verified by an additional batch of 100 allografts. The results from this validation indicate that sterility (10(-6) SAL) on human allograft tissue using gamma 60Co radiation can be achieved when a dose of at least 9.2 kGy is employed.
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