Isocenter Verification in Radiotherapy based on Automatic Image Registration

Abstract

AbstractIn the present study, a non-rigid image registration method was employed for verification of the radiotherapy isocenter position. The registration method was applied to the CT scan of the treatment planning and an additional verification CT scan, which was acquired prior to the treatment delivery. The alignment of the two CT scans allowed the estimation of the isocenter displacement with respect to the initial isocenter position in the planning CT volume. The results, acquired from the CT scans of twenty patients with breast/lung cancer, were compared with the actual setup errors, estimated using DRR and EPI in the clinical practice. This comparison led to the conclusion that the isocenter displacement, calculated by the proposed method, can further be translated into patient setup error inside the LINAC, providing a good approximation of the setup error correction of the DRR/EPI comparison.KeywordsRegistration MethodSetup ErrorImage Registration MethodAutomatic Image RegistrationIsocenter PositionThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.