Abstract: A method for determining a beam parameter of an unflattened photon beam generated by an accelerator includes measuring radiation dose values in the plane perpendicular to the beam propagation direction, determining the extension of the unflattened beam using a definition of the beam extension of a flattened beam. The method also includes normalizing the radiation dose values, such that essentially the same value for the extension of the unflattened beam is obtained as would be obtained if the beam was flattened and determining the beam parameter of the unflattened beam using a beam parameter definition of a flattened beam.

Abstract: An apparatus and a method for determining a beam parameter of an asymmetrical photon beam generated by an accelerator are provided. A beam profile of a symmetrical photon beam is measured and normalized. For the asymmetrical photon beam, a normalization of the beam profile is implemented such that the maximum of the profile corresponds to a value of the normalized symmetrical beam profile at the site of the maximum. The parameter determination takes place using a conventional beam parameter definition.

Abstract: Multileaf collimator calibration includes defining a reference position of a carriage and determining a first value, the first value being for a drift of a first position of a leaf from a first defined absolute position, the leaf being arranged on the carriage and the carriage being located at the reference position. The multileaf calibration also includes moving the carriage to a position to be checked and determining a second value, the second value being for a drift of a second position of a leaf from a second defined absolute position, the carriage being located at the position to be checked. A difference value is determined by forming the difference between the first value and the second value for the drift of the position of the leaf and using the difference value as a value for the drift of the position of the carriage for the position to be checked.

Abstract: An apparatus and a method for determining a beam parameter of an asymmetrical photon beam generated by an accelerator are provided. A beam profile of a symmetrical photon beam is measured and normalized. For the asymmetrical photon beam, a normalization of the beam profile is implemented such that the maximum of the profile corresponds to a value of the normalized symmetrical beam profile at the site of the maximum. The parameter determination takes place using a conventional beam parameter definition.

Abstract: A method for determining a beam parameter of an unflattened photon beam generated by an accelerator includes measuring radiation dose values in the plane perpendicular to the beam propagation direction, determining the extension of the unflattened beam using a definition of the beam extension of a flattened beam.