Radiotherapy Center, Chenzhou No. 1 People's Hospital, Hunan, China.
Radiotherapy Center, Chenzhou No. 1 People's Hospital, Hunan, China; Department of Radiation Oncology, Yee Zen General Hospital, Yang Mei, Taiwan.
Med Dosim. 2020;45(3):246-251. doi: 10.1016/j.meddos.2020.01.004. Epub 2020 Feb 25.
We investigated to what extent can the dose-volumes of the coronary artery and the cardiac substructures be reduced by using IMRT technique in left-sided breast cancer patients. We chose 40 pN2M0 patients treated with postmastectomy IMRT. The original treatment plans were retrieved and the (internal mammary nodes) IMNs and cardiac substructure delineations were added. Three sets of dose-volume parameters including the original plans without internal mammary irradiation (IMNI), the plans with IMNI, and the plans with dose constraints to the heart, were derived. In left-sided patients, when IMNI was included, the V30 for right ventricle (RV), left ventricle (LV), pulmonic valve (PV), and left anterior descending artery (LADA) were 56.37% ± 7.9%, 25.3% ± 7.3%, 48.3% ± 6.3%, and 69.7% ± 6.4%, respectively. Of the 4 main coronary arteries, LADA had the highest dose followed by the left main coronary artery (LMCA). LADA had a V40 of 62% ± 9.7% vs 13.5% ± 3.5%, and a V50 of 27.5% ± 4.7% vs 0, with and without IMNI. For the right-sided patients, the V30s for all the heart substructures were 0 with or without IMNI. When we set a dose constraint of V40 < 10% for the LADA in the left-sided patients, the PTV volumes covered by 50 Gy decreased by only 1%. IMNI increased the V30 of the right and left ventricle and significantly increased the V40 and V50 to the LADA of left-sided breast cancer patients. IMRT markedly reduces the dose to the main coronary arteries and the right and left ventricle.
我们研究了在左侧乳腺癌患者中使用调强放疗（IMRT）技术可以在多大程度上减少冠状动脉和心脏亚结构的剂量-体积。我们选择了 40 例 pN2M0 接受术后 IMRT 治疗的患者。检索了原始治疗计划，并添加了（内乳淋巴结）IMNs 和心脏亚结构勾画。得出了三组剂量-体积参数，包括无内乳照射（IMNI）的原始计划、包含 IMNI 的计划和心脏剂量限制的计划。在左侧患者中，当包含 IMNI 时，右心室（RV）、左心室（LV）、肺动脉瓣（PV）和左前降支（LADA）的 V30 分别为 56.37%±7.9%、25.3%±7.3%、48.3%±6.3%和 69.7%±6.4%。在 4 条主要冠状动脉中，LADA 的剂量最高，其次是左主干冠状动脉（LMCA）。LADA 的 V40 分别为 62%±9.7%和 13.5%±3.5%，V50 分别为 27.5%±4.7%和 0，有或无 IMNI。对于右侧患者，无论是否进行 IMNI，所有心脏亚结构的 V30 均为 0。当我们在左侧患者中设定 LADA 的 V40<10%的剂量限制时，仅 50 Gy 覆盖的 PTV 体积减少了 1%。IMNI 增加了右侧和左侧心室的 V30，并显著增加了左侧乳腺癌患者 LADA 的 V40 和 V50。IMRT 显著降低了主要冠状动脉和右侧和左侧心室的剂量。
