Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Radiation Oncology cung cấp cho các bạn kiến thức về ngành y đề tài: " Fractionated stereotactic radiotherapy for skull base tumors: analysis of treatment accuracy using a stereotactic mask fixation system. | Minniti et al. Radiation Oncology 2010 5 1 http content 5 1 1 RADIATION ONCOLOGY METHODOLOGY Open Access Fractionated stereotactic radiotherapy for skull base tumors analysis of treatment accuracy using a stereotactic mask fixation system Giuseppe Minniti1 2 Maurizio Valeriani1 Enrico Clarke1 Marco D Arienzo3 Michelangelo Ciotti3 Roberto Montagnoli1 Francesca Saporetti1 Riccardo Maurizi Enrici1 Abstract Background To assess the accuracy of fractionated stereotactic radiotherapy FSRT using a stereotactic mask fixation system. Patients and Methods Sixteen patients treated with FSRT were involved in the study. A commercial stereotactic mask fixation system BrainLAB AG was used for patient immobilization. Serial CT scans obtained before and during FSRT were used to assess the accuracy of patient immobilization by comparing the isocenter position. Daily portal imaging were acquired to establish day to day patient position variation. Displacement errors along the different directions were calculated as combination of systematic and random errors. Results The mean isocenter displacements based on localization and verification CT imaging were mm SD mm in the lateral direction mm SD mm in the anteroposterior and mm SD mm in craniocaudal direction. The mean 3D displacement was mm SD mm being maximum mm. No significant differences were found during the treatment P . The overall isocenter displacement as calculated by 456 anterior and lateral portal images were mm SD mm in the mediolateral direction mm SD 1 mm in the anteroposterior direction and mm SD mm in the craniocaudal direction. The largest displacement of mm was seen in the cranio-caudal direction with 95 of displacements 2 mm in any direction. Conclusions The results indicate that the setup error of the presented mask system evaluated by CT verification scans and portal imaging are minimal. Reproducibility of the isocenter position is
