Abstract: A method for dose guidance for a radiotherapy system during a radiotherapy session includes the steps of: performing substantially real-time dose reconstruction to obtain a delivered radiation dose generated by a radiotherapy beam of the radiotherapy system in at least one volume; repeatedly estimating a remaining radiation dose based on an observed and/or simulated motion of the at least one volume; repeatedly estimating a final delivered radiation dose as a sum of the delivered radiation dose and the estimated remaining radiation dose; and providing dose guidance for a remaining part of the radiotherapy session based on the estimated final delivered radiation dose. A method of continuous estimation of final delivered radiation dose during a radiotherapy session and a decision support system for a radiotherapy system are also provided.

Abstract: Computed axial tomography images of different respiratory phases of lungs are obtained, where the intensity of the image measures lung density. One image is deformed to the coordinate space of the other image, and the differences between the intensity values of the other image as compared to the mapped image are evaluated as measures of ventilation.