a method provides for sterilizing with radiation objects which have a low bioburden and which are sensitive to radiation . a dosage of radiation sufficient to ensure sterilization without damaging the object is determined by determining the bioburden upon one or more samples of the objects , determining an estimate of the dose that results in a probability of 0 . 01 of a surviving microorganism by testing a quantity of samples of the objects at varying dosage levels of radiation , confirming the estimate by testing a quantity of samples of the objects at the dose that was estimated ; and calculating a dosage for the sterility assurance level of 10 - 6 by adding a factor to the dose that was confirmed to result in a probability of 0 . 01 of a surviving microorganism and wherein the factor is proportional to the dose that yields a probability of 0 . 01 of a surviving microorganism and inversely proportional to a log of the bioburden .