Field matching of 6 MeV X-Ray asymmetric collimated fields for radiotherapy patients

Asymmetric X-ray fields are used in cancer therapy to eliminate the problem of beam divergence with depth. A study of the dose distribution resulting from asymmetric fields being matched with both symmetric and asymmetric fields is presented. Forming functions are used by computer planning systems to model the way X-ray beams interact with the body of the patient. The properties of two forming functions are compared with a possible alternative function.