标题：Dosimetric impact of tumor bed delineation variability based on 4DCT scan for external-beam partial breast irradiation
作者：Guo, Bing; Li, Jianbin; Wang, Wei; Li, Fengxiang; Guo, Yanluan; Li, Yankang; Liu, Tonghai
作者机构：[Guo, Bing; Li, Jianbin; Wang, Wei; Li, Fengxiang; Guo, Yanluan; Liu, Tonghai] Shandong Canc Hosp & Inst, Dept Radiat Oncol, 440 Jiyan Rd, Jinan 25011 更多
通讯作者地址：[Li, JB]Shandong Canc Hosp & Inst, Dept Radiat Oncol, 440 Jiyan Rd, Jinan 250117, Shandong, Peoples R China.
来源：INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL MEDICINE
关键词：Breast cancer; external beam partial breast irradiation;; four-dimensional computed tomography; clips; seroma
摘要：This study sought to evaluate the dosimetric impact of tumor bed delineation variability (based on clips, seroma or both clips and seroma) during external-beam partial breast irradiation (EB-PBI) planned utilizing fourdimensional computed tomography (4DCT) scans. 4DCT scans of 20 patients with a seroma clarity score (SCS) 3 similar to 5 and >= 5 surgical clips were included in this study. The combined volume of the tumor bed formed using clips, seroma, or both clips and seroma on the 10 phases of 4DCT was defined as the internal gross target volume (termed IGTV(C), IGTV(S) and IGTV(C+S), respectively). A 1.5-cm margin was added by defining the planning target volume (termed PTVC, PTVS and PTVC+S, respectively). Three treatment plans were established using the 4DCT images (termed EBPBIC, EB-PBIS, EB-PBIC+S, respectively). The results showed that the volume of IGTV(C+S) was significantly larger than that of IGTV(C) and IGTV(S). Similarly, the volume of PTVC+S was markedly larger than that of PTVC and PTVS. However, the PTV coverage for EB-PBIC+S was similar to that of EB-PBIC and EB-PBIS, and there were no significant differences in the homogeneity index or conformity index between the three treatment plans (P=0.878, 0.086). The EB-PBIS plan resulted in the lowest ipsilateral normal breast and ipsilateral lung doses compared with the EB-PBIC and EB-PBIC+S plans. To conclude, the volume variability delineated based on clips, seroma or both clips and seroma resulted in dosimetric variability for organs at risk, but did not show a marked influence on the dosimetric distribution.