A system to acquire a first image of a radiation field, the radiation field produced by a radiation beam, and to determine a second image based on the first image and based on a reference image of a reference radiation field having substantially homogeneous intensity, the second image representing characteristics of the radiation beam. Some embodiments provide acquisition of a first profile associated with a radiation beam using a radiation detection device, acquisition of a first image of a first radiation field produced by the radiation beam using an imaging device, determination of a map between the first image and the first profile, acquisition a second image of a second radiation field using the imaging device, and determination of a second profile based on the map and the second image.