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 preselected probability (e.g., 0.1, 0.01, 0.001, 0.0003162 . . . etc. (i.e., SAL=10−1, 10−2, 10−3, 10−3.5 . . . etc.)) of a surviving microorganism on the objects preferably 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 said preselected probability of a surviving microorganism on the objects and wherein the factor is proportional to the dose that yields said preselected probability of a surviving microorganism on the objects and inversely proportional to a log of the bioburden.
