A method for determining dosages received by a product to be exposed to a treatment source at least one defined location from the treatment source. One exemplary method includes defining a point on the product (Fig.3, item 138). Then, fixed zones and variable zones are defined. Next, pre-calculated lengths between the point on the product and the treatment source are identified at each of the at least one defined location (Fig.4, item 158) Then, a dosage of treatment to be received by the point on the product at each of the at least one defined location is calculated (Fig.4, item 160), wherein the calculation uses the pre-calculated lengths. An apparatus for exposing a product to a treatment and a treatment system are also provided.