TY - JOUR ID - 14033 TI - Evaluation of Six-Dimensional Cranial Target Positioning Accuracy in Two Different Immobilization Methods Using Exactrac System JO - Iranian Journal of Medical Physics JA - IJMP LA - en SN - AU - Kasirajan, Tamil Selvan AU - Ganesan, Padma AU - Murugesan Kesavan, Revathy AU - N, Arunai Nambi Raj AU - K, Senthilnathan AU - P, Ramesh Babu AD - Department of Oncology, Apollo Cancer Hospital, Hyderabad, Telangana, India AD - Centre for Biomaterials, Cellular and Molecular Theranostics, Vellore Institute of Technology, Vellore, Tamil Nadu, India AD - Department of Physics, School of Advanced Sciences, Vellore Institute of Technology, Vellore, Tamil Nadu, India Y1 - 2020 PY - 2020 VL - 17 IS - 5 SP - 308 EP - 315 KW - Radiotherapy KW - patient positioning KW - Radiosurgery KW - Radiotherapy Setup Errors KW - Immobilization DO - 10.22038/ijmp.2019.35652.1448 N2 - Introduction: The aim of this study was to determine the accuracy of two different immobilization methods in patient positioning in cranial radiotherapy. The six-dimensional (6D) target localization accuracy of using a dedicated stereotactic mask was compared with that of a conventional head mask by the ExacTrac system. Material and Methods: A total of 56 patients with cranial lesions were included in this study (26 patients with a dedicated stereotactic mask and 30 subjects with a conventional head mask). The ExacTrac image-guided positioning system was utilized to obtain daily translational and rotational patient positioning displacement from the intended position. The 6D setup data was analyzed to obtain population mean, systematic and random errors, and three-dimensional (3D) vector shifts in all the patients. Results: The population mean values of setup errors were comparable with both immobilization systems; however, the spread as indicated by population systematic and population random errors was more in the use of a conventional head mask. The mean values of the 3D vector shifts were 2.09±1.00 and 4.51±3.38 mm with the use of a dedicated stereotactic mask and conventional head mask, respectively. The frequency distribution of maximum rotational deviation and statistical analysis demonstrated a significant difference in immobilization accuracy between stereotactic immobilization and 3-clamp immobilization (p <0.05). Conclusion: The results revealed that there was a significant reduction in target positioning errors with a dedicated stereotactic mask, compared to that with a conventional cranial mask. Furthermore, a dedicated stereotactic mask is required to keep rotational deviations within system correctable limits. UR - https://ijmp.mums.ac.ir/article_14033.html L1 - https://ijmp.mums.ac.ir/article_14033_43e7e82560ce1e894362e02c63e92160.pdf ER -