A method for the reconstruction of a dose administered in an object to be irradiated includes providing a radiation therapy device. The radiation therapy device includes a therapeutic radiation source for emitting a therapeutic treatment beam, a portal detector opposing the therapeutic radiation source for recording measurement data of the treatment beam once the therapeutic radiation source has left the object to be irradiated, and a single or multi slice computed tomography scanner having a kV x-ray source and an opposing kV detector for producing a computed tomography of the object positioned in the radiation therapy device. The method also includes recording a computed tomography image of the object to be irradiated with the computed tomography scanner, and using the computed tomography image in order to reconstruct a dose administered to the object from measurement data of the portal detector.
