[Comparison of the volume and localization of internal gross target volume and planning target volume delineated by clips and XXXX based on 4D-CT scan for external-beam partial breast irradiation after breast conserving surgery].

@entity1 @entity0 @entity5 @entity2080 @entity343
OBJECTIVE: To explore the differences in volume and localization of the internal gross target volume and planning target volume delineated by clips and/or @entity2080 based on four-dimensional computed tomography (4D-CT) during free-breathing in @entity0 @entity1 after breast conserving surgery. METHODS: Fifteen @entity0 @entity1 after breast-conserving surgery (BCS) were recruited for external-beam partial breast irradiation (EB-PBI). On the ten sets CT images, the gross @entity5 volumes (GTV) formed by the clips, the @entity2080 , and both the clips and @entity2080 were delineated and defined as GTVc, GTVs and GTVc+s, respectively. Ten GTVc, GTVs and GTVc+s on the ten sets CT images produced the IGTVc, IGTVs, IGTVc+s. The PTVc, PTVs, PTVc+s were created by adding 15 mm to the IGTVc, IGTVs, IGTVc+s, respectively. The IGTV and @entity343 volume and distance between the centers of IGTVc, IGTVs, IGTVc+s and PTVc, PTVs, PTVc+s were all recorded. Conformity index (CI) and degree of inclusion (DI) were calculated for IGTV/IGTV and @entity343 / @entity343 , respectively. RESULTS: The volume of IGTVc+s[(35.73    19.77) cm(3)] was significantly larger than the IGTVc [(28.35    17.54) cm(3)] and IGTVs [(24.19    21.53) cm(3)] (P < 0.05), and the volume of PTVc+s [(191.59    69.74) cm(3)] was significantly larger than that of the PTVc [(161.53    61.07) cm(3)] and PTVs [(148.98    62.22)cm(3)] (P < 0.05). There were significant differences between the DIs of IGTVc in IGTVc+s and IGTVc+s in IGTVc, the DIs of IGTVs in IGTVc+s and IGTVc+s in IGTVs, the DIs of PTVc in PTVc+s and PTVc+s in PTVc, and the DIs of PTVs vs. PTVc+s and PTVc+s in PTVs (P < 0.05 for all). The CI of IGTVc/IGTVc+s (0.63    0.14) and the CI of IGTVs/IGTVc+s (0.54    0.17) were significant larger than that of the CI of IGTVc/IGTVs (0.40    0.14)(P < 0.05). There were non-significant differences among the CI of PTVc/PTVs, PTVc/PTVc+s and PTVs/PTVc+s (0.73    0.12, 0.78    0.13 vs. 0.75    0.17). The DIs and CIs of IGTV/IGTV and @entity343 / @entity343 were negatively correlated with their centroid distance (P < 0.05). CONCLUSIONS: There are volume difference and spatial mismatch between the target volumes delineated on the basis of surgical clips and @entity2080 . The DI and CI between the PTVs are larger than that between the IGTV. External-beam partial breast irradiation should be implemented based on the @entity343 that is defined based on both @entity2080 .
