Department of Oncology,Sichuan Academy of Medical Science& Sichuan Provincial People’s Hospital,Chengdu 610072,China (Peng Q);Department of Radiation Oncology,Sichuan Cancer Hospital,Chengdu 610041,China (Wang P,Wang XL,Cheng CHD,Liu LH,Huang CHJ)
Abstract： Objective To analyze the setup errors of external-beam and intracavitary radiotherapy for cervical cancer based on the data of cone-beam computed tomography (CBCT), and to provide a basis for clinical practice. Methods Sixty patients with stage ⅡA-ⅢB cervical cancer who were admitted to our hospital and underwent external-beam and intracavitary radiotherapy from March to June, 2015 were enrolled as subjects. Sixty patients with stage ⅡA-ⅢB cervical cancer undergoing conventional external-beam radiotherapy within the same period were also enrolled. The CBCT-based setup errors, containing setup errors in x, y, and z directions and three-dimensional vector deviation, in the initial treatment were obtained from each patient. Comparison of errors between the two treatment approaches was made by independent-samples t test. Results Fitting the data to a linear model revealed that the setup errors in x, y, and z directions increased with the increase in the distance between the position reference point and the center point of the target volume. External-beam radiation combined with intracavitary radiation had significantly reduced setup errors in x, y, and z directions than the conventional external-beam radiation (0.13±0.12 vs. 0.31±0.24, P=0.000;0.23±0.18 vs. 0.47±0.36, P=0.001;0.18±0.11 vs. 0.27±0.18, P=0.001). Conclusions In order to reduce the setup errors, CT scan needs not only a reference marker as close as possible to the center of the tumor, but also a reliable and accurate approach for postural fixation.
Peng Qian,Wang Pei,Wang Xianliang et al. Setup errors of external-beam and intracavitary radiotherapy for cervical cancer:an analysis based on cone-beam computed tomography[J]. Chinese Journal of Radiation Oncology, 2016, 25(10): 1113-1116.
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2016, Vol. 25 
