摘要
目的探讨保乳术后全乳调强放疗中标记夹所形成几何体体积、位置、形态的变化规律及相关影响因素。方法回顾性分析2021年10月至2022年9月苏州大学附属第一医院18例保乳术后调强放疗患者,依据定位CT和放疗0、10、20、30、40、50 Gy时的锥形束CT(CBCT),读取瘤床标记夹坐标信息,获取每次摆位误差。利用凸包计算程序构建几何体,分别计算出几何体基于定位CT的体积(V_(ct))、6次CBCT的体积(V0~5);比较6次CBCT与定位CT的几何体质心位移(D_(0-5))和包含度(DI_(0-5))。照射剂量分别对V0~5、D_(0-5)、DI_(0-5)的影响采用配对t检验或秩和检验;D_(0-5)分别与同次三维方向摆位误差的相关性,V0~5变化率均值(AV)、D_(0-5)均值(AD)、DI_(0-5)均值(ADI)分别与体质量指数(BMI)、全乳体积(VB)、乳轴高(H)、手术至放疗时间间隔(T)的相关性,均采用Pearson相关分析;几何体所处象限(Q)和几何体于胸壁贴离状态(S)分别对AV、AD、ADI的影响采用单因素方差分析。结果D_(5)与D0、D_(1)、D_(2)差异均有统计学意义(t=-3.27、-4.52、-3.38,P<0.05);DI5与DI0、DI_(1)、DI_(2)差异有统计学意义(t=2.53、2.70、2.64,P<0.05);D_(1)和D_(4)、D_(3)分别与头脚、左右方向误差相关(r=0.50、0.56、0.53,P<0.05),AD与BMI、VB、H相关(r=0.54、0.48、0.50,P<0.05);几何体离胸壁(S_(3))与近胸壁(S_(2))的AV和ADI差异均有统计学意义(F=2.66、3.83,P<0.05);S_(3)与几何体贴胸壁(S_(1))和S_(2)的AD差异均有统计学意义(F=7.46,P<0.05)。结论全乳放疗中几何体体积相对恒定,但放疗后程位置、形态变化较大。几何体体积变化率、质心位移、包含度均受其于胸壁贴离状态的影响,质心位移与乳腺形态、BMI存在相关性,放疗计划和是否修改可个体化。
Objective To investigate the variations and related influencing factors of the volumes,positions,and morphologies of geometries formed by surgical clips in intensity-modulated radiation therapy(IMRT)for whole breasts after breast-conserving surgery.Methods A retrospective analysis was conducted on 18 patients treated with IMRT from October 2021 to September 2022 after breastconserving surgery.Set-up errors were obtained by reading the coordinate information of tumor bed surgical clips according to the cone beam CT(CBCT)images at 0,10,20,30,40,and 50 Gy sequentially.Geometries were constructed using the convex hull program,and the volumes(V_(ct) and V_(0-5))of geometries were then calculated based on the localization CT images and the six CBCT images,respectively.The centroid displacements(D_(0-5))and degrees of inclusion(DI0-5)of these geometries were compared.The t-test or rank-sum test was used to analyze the effects of radiation doses on V_(0-5),D_(0-5),and DI0-5.The Pearson correlation analysis was conducted to analyze the correlations between D_(0-5) and corresponding setup errors in three-dimensional directions,and the correlations of average V_(0-5) variation(AV),average D_(0-5)(AD),and average DI0-5(ADI)with the body mass index(BMI),the volume of a breast(VB),the breast axial height(H),and the time interval from surgery to radiotherapy(T)each.The influences of quadrants(Q)where geometries are located and states(S)of geometries adhering to or away from the chest walls on AV,AD,and ADI were analyzed through one-way ANOVA.Results The differences between D_(5) and D0,between D_(5) and D_(1),and between D_(5) and D_(2) were statistically significant(t=-3.27,-4.52,-3.38,P<0.05),respectively.The differences between DI_(5) and DI0,between DI_(5) and DI_(1),between DI_(5) and DI_(2) were statistically significant(t=2.53,2.70,2.64,P<0.05),respectively.D_(1) and D_(4) correlated with the set-up errors in the superior-inferior dimension,and D_(3) correlated with the set-up errors in the left-right dimension(r=0.50,0.
作者
宋伟
李清山
符天晓
Song Wei;Li Qingshan;Fu Tianxiao(Department of Radiation Oncology,First Affiliated Hospital of Soochow University,Suzhou 215006,China)
出处
《中华放射医学与防护杂志》
CAS
CSCD
北大核心
2023年第7期532-538,共7页
Chinese Journal of Radiological Medicine and Protection
关键词
乳腺癌
保乳术后放疗
标记夹
几何变化
Breast cancer
Radiotherapy after breast-conserving surgery
Surgical clip
Geometry variation
