A method for quantifying radiation beam conformity includes: obtaining first information regarding a prescribed aperture； obtaining second information regarding an actual aperture defined by components of a collimator； and determining, using a processing unit, a metric based on the first information regarding the prescribed aperture and the second information regarding the actual aperture, wherein the metric indicates an amount of over-exposed aperture area, an amount of under-exposed aperture area, or both, and wherein the processing unit comprises one or more input for receiving the first and second information, and comprises a metric determination module configured to determine the metric based on the first information and the second information.
