Evaluation of set-up errors and improvement of precision of tomotherapy in head and neck tumors / 医疗卫生装备

ABSTRACT

Objective To analyze the factors for tomotherapy precision related to the setup errors in the head and neck tumors to enhance the radiotherapy precision.Methods Totally 35 head and neck tumor patients from February to July 2016 were enrolled into the study,MVCT scan was executed before each time of tomotherapy and setup flow was standardized.There were 1 092 errors sets for the setup guided by MVCT image analyzed,and the method for reducing the setup error and the standardized process for enhancing the tomotherapy precision were put forward accordingly.Results The setup errors at X,Y and Zdirections were (0.98±0.91),(1.63±1.22),(1.11±0.87) mm originally,and became (0.97±089),(1.58±1.08),(1.06±0.83) mm after manual matching,and the setup error gained maximum value at Y direction and minimum value at X direction.The numbers of cases with the setup error not less than 3 mm were 6,49 and 18 respectively at X,Y and Z directions,and the corresponding proportions were 0.55％,4.49％ and 1.65％ respectively.The setup error for the tomotherapy in the head and neck tumors was low,and matching contributed to reducing the setup error.Conclusion There are multi factors affecting the setup error of the tomotherapy of the head and neck tumors,and the measures to decrease the setup error include strict institutions,standardized quality control and enhanced radiologist level.