Exploring the effects of abdominal circumference on setup errors in colorectal cancer radiotherapy using CBCT-guided techniques
10.3969/j.issn.1005-202X.2025.07.005
- VernacularTitle:基于锥形束CT图像引导技术研究腹围对结直肠癌放疗摆位误差的影响
- Author:
Di WU
1
;
Tao XUE
1
;
Kun LI
1
;
Heng ZHANG
1
;
Huaqing WANG
1
;
Hui WANG
1
Author Information
1. 天津市人民医院/南开大学第一附属医院肿瘤诊疗中心,天津 300121;南开大学人民医院转化医学研究院,天津 300121;天津市中西医结合肿瘤研究所,天津 300121
- Publication Type:Journal Article
- Keywords:
rectal cancer;
setup error;
cone-beam computed tomography;
intensity-modulated radiotherapy;
abdominal circumference
- From:
Chinese Journal of Medical Physics
2025;42(7):872-877
- CountryChina
- Language:Chinese
-
Abstract:
Objective By establishing a model to screen out patients with potentially large positional deviations based on their abdominal circumference,personalized solutions can be taken to address setup errors in these patients and ensure treatment efficacy.Methods A total of 81 patients treated at Tianjin People's Hospital from May 2021 to June 2023 were selected as the study subjects.The correlations between setup errors in the lateral,longitudinal,and vertical directions and abdominal circumference were analyzed.Subsequently,linear regression was performed for the direction with a significant correlation to abdominal circumference to establish a linear regression model.Finally,the 81 patients were divided into a normal setup group and an abnormal setup group with 0.7 cm as the critical value.A receiver operating characteristic(ROC)curve was plotted,and the maximum Youden index was calculated to determine the optimal cutoff value for identifying patients prone to abnormal setup.Results The correlation analysis of abdominal circumference and setup errors in various directions showed that the correlation coefficient between abdominal circumference and longitudinal direction positioning error was 0.406 2,and the correlation was statistically significant and positively correlated.The correlation coefficients for abdominal circumference and the lateral as well as longitudinal directions were-0.117 5 and-0.067 47,respectively,with P values greater than 0.05,indicating no statistical significance.A linear regression model was established for abdominal circumference and longitudinal direction,and the results showed an R2of 0.165,with a regression coefficient B of 0.008(t=3.951,P<0.01),indicating that the model was well constructed.ROC curve analysis showed an area under the curve of 0.715,with a 95%confidence interval of 0.57-0.86 and a maximum Youden index of 0.478.The corresponding optimal cutoff value was determined to be at 87 cm,with sensitivity at 0.875 and specificity at 0.603.Conclusion The abdominal circumference is significant to diagnose whether the longitudinal setup error is abnormal.Patients with an abdominal circumference greater than 87 cm are more likely to experience abnormal positioning during radiotherapy,which is reflected in the longitudinal setup errors being the largest.It is recommended to provide individualized target area margins for patients with an abdominal circumference greater than 87 cm,or perform daily cone-beam computed tomography to correct setup errors,thereby ensuring target coverage and treatment efficacy.
