Abstract: A process is presented for determining the effectiveness of sterilization processes for medical devices, with the steps of: providing a data structure, wherein the data structure represents a grid formed of a plurality of three-dimensional cells, recreating the medical device arranged in the sterilizer in the data structure in such a way that a first plurality of cells of the grid represent a body of the medical device and that a second plurality of cells represent an interior of the sterilizer which is not occupied by the body of the medical device, recreating an initial state in the data structure in such a way that each cell of the second plurality of cells is assigned data with respect to the temperature prevailing at the location of the cell, the quantity of a first medium located in the area of the cell and the quantity of a second medium located in the area of the cell, recreating, step by step, changes in the temperature, the quantity of the first medium and the quantity of the second medium occurring