Abstract: The present invention is directed to a method for radiation beam therapy delivery system normalization and dose calibration. A prescribed treatment plan is compared to a database of pre-existing and pre-calibrated treatment plans. Upon existence of a matching plan, appropriate calibration factors are assigned to the delivery system monitors according to the pre-existing plan. Variations in delivery system operation are corrected by independent correction of all delivery system monitors established by standard relative calibration taken prior to patient treatment. The advantages of the present invention are particularly significant for proton therapy facilities containing a plurality of delivery systems. The method permits a prescribed treatment to be administered with accuracy not only at the station associated with the initial treatment planning, but at any available delivery station.

Abstract: A radiation treatment apparatus comprises a source of charged particles, preferably protons, for producing a particle beam, and a scattering foil for changing the diameter of the charged particle beam. The scattering foil is configured so that its thickness is both uniform and continuously adjustable throughout a range of thicknesses.