Ding Yun, Li Jianbin, Wang Wei, Wang Suzhen, Wang Jinzhi, Ma Zhifang
Department of Radiation Oncology, Shandong Cancer Hospital, Jinan 250117, China.
Department of Radiation Oncology, Shandong Cancer Hospital, Jinan 250117, China. Email:
Zhonghua Zhong Liu Za Zhi. 2014 Oct;36(10):766-70.
To explore the differences in volume and localization of the internal gross target volume and planning target volume delineated by clips and/or seroma based on four-dimensional computed tomography (4D-CT) during free-breathing in breast cancer patients after breast conserving surgery.
Fifteen breast cancer patients after breast-conserving surgery (BCS) were recruited for external-beam partial breast irradiation (EB-PBI). On the ten sets CT images, the gross tumor volumes (GTV) formed by the clips, the seroma, and both the clips and seroma 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 PTV 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 PTV/PTV, respectively.
The volume of IGTVc+s[(35.73 ± 19.77) cm³] was significantly larger than the IGTVc [(28.35 ± 17.54) cm³] and IGTVs [(24.19 ± 21.53) cm³] (P < 0.05), and the volume of PTVc+s [(191.59 ± 69.74) cm³] was significantly larger than that of the PTVc [(161.53 ± 61.07) cm³] and PTVs [(148.98 ± 62.22)cm³] (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 PTV/PTV were negatively correlated with their centroid distance (P < 0.05).
There are volume difference and spatial mismatch between the target volumes delineated on the basis of surgical clips and seroma. 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 PTV that is defined based on both seroma and surgical clips.
探讨保乳手术后乳腺癌患者在自由呼吸状态下，基于四维计算机断层扫描（4D-CT），由金属夹和/或血清肿所勾画的内部大体靶区体积和计划靶区体积的差异。
招募15例保乳手术（BCS）后的乳腺癌患者进行外照射部分乳腺放疗（EB-PBI）。在10组CT图像上，分别勾画由金属夹、血清肿以及金属夹和血清肿共同形成的大体肿瘤体积（GTV），并分别定义为GTVc、GTVs和GTVc+s。10组CT图像上的10个GTVc、GTVs和GTVc+s生成IGTVc、IGTVs、IGTVc+s。分别在IGTVc、IGTVs、IGTVc+s基础上外放15 mm创建PTVc、PTVs、PTVc+s。记录IGTV和PTV的体积以及IGTVc、IGTVs、IGTVc+s与PTVc、PTVs、PTVc+s中心之间的距离。分别计算IGTV/IGTV和PTV/PTV的适形指数（CI）和包容度（DI）。
IGTVc+s的体积[（35.73±19.77）cm³]显著大于IGTVc[（28.35±17.54）cm³]和IGTVs[（24.19±21.53）cm³]（P<0.05），PTVc+s的体积[（191.59±69.74）cm³]显著大于PTVc[（161.53±61.07）cm³]和PTVs[（148.98±62.22）cm³]（P<0.05）。IGTVc在IGTVc+s中的DI与IGTVc+s在IGTVc中的DI、IGTVs在IGTVc+s中的DI与IGTVc+s在IGTVs中的DI、PTVc在PTVc+s中的DI与PTVc+s在PTVc中的DI以及PTVs与PTVc+s的DI和PTVc+s在PTVs中的DI之间均存在显著差异（均P<0.05）。IGTVc/IGTVc+s的CI（0.63±0.14）和IGTVs/IGTVc+s的CI（0.54±0.17）显著大于IGTVc/IGTVs的CI（0.40±0.14）（P<0.05）。PTVc/PTVs、PTVc/PTVc+s和PTVs/PTVc+s的CI之间差异无统计学意义（0.73±0.12、0.78±0.13对0.75±0.17）。IGTV/IGTV和PTV/PTV的DI和CI与其质心距离呈负相关（P<0.05）。
基于手术金属夹和血清肿勾画的靶区体积存在差异和空间不匹配。PTV之间的DI和CI大于IGTV之间的。外照射部分乳腺放疗应基于同时考虑血清肿和手术金属夹所定义的PTV来实施。
