A method of validating a compensator for use in a radiation therapy machine to treat a cancer patient involves determining a radiation treatment plan based on a compensator description file that includes data representative of an actual machined surface of the compensator. The plan includes operating parameters of the radiation therapy machine, and this plan is compared against actual radiation measurements taken during a non-patient test of the radiation therapy machine with the compensator mounted to the machine. If the comparison results in a match, the compensator is validated for use in the radiation therapy machine to treat the cancer patient.