■这项研究的目的是评估左侧乳腺癌患者的三种照射技术,三维适形放射治疗(3D-CRT),混合调强放射治疗(h-IMRT),和混合体积调制电弧治疗(h-VMAT,h-ARC),在计划目标体积(PTV)和危险器官(OAR)中的剂量分布方面。第二个目的是估计混合技术的辐射诱导的继发性癌症的预测相对风险。
■在3D-CRT中准备了三种治疗方案,h-IMRT,和h-VMAT技术为40名患者,在深吸气屏气(DIBH)中接受了CT模拟。对于混合技术,计划是通过将3D-CRT和动态场与3D-CRT和IMRT或VMAT的80%/20%剂量比相结合来创建的。累积剂量-体积直方图用于比较PTV和OAR内的剂量分布(心脏,左冠状动脉前降支[LAD],左、右肺[LL,RL],右乳房[RB])。使用施耐德线性指数的器官等效剂量(OED)概念相对于3D-CRT估计继发性癌症的预测风险比,高原,和完整的机械剂量反应模型。
■所有计划均符合PTV标准:V95%≥95%。与3D-CRT相比,两种混合技术均显示出明显更好的目标覆盖率(PTV:V95%>98%,p<0.001),h-ARC计划可达到最佳保形度(CI:1.18±0.09,p<0.001)。与3D-CRT和h-ARC相比,h-IMRT使监测单位(MU)的平均总和增加超过129.9%(p<0.001)。H-ARC增加对侧器官的平均剂量和LLV5Gy参数(p<0.001)。两种混合技术均使心脏的Dmax显着降低了5Gy。与h-IMRT相比,h-ARC增加了继发性癌症预测的LL的相对风险比,RL,RB分别为18、152和81%,分别。
■结果证实,两种混合技术都比3D-CRT提供更好的目标质量和OAR节省。与混合IMRT相比,混合VMAT递送较少的MU,但可能增加辐射诱导的继发性恶性肿瘤的风险。
UNASSIGNED: The purpose of this study was to evaluate three techniques of irradiation of left-sided breast cancer patients, three-dimensional conformal radiotherapy (3D-CRT), hybrid Intensity-Modulated Radiotherapy (h-IMRT), and hybrid Volumetric-Modulated Arc Therapy (h-VMAT, h-ARC), in terms of dose distribution in the planning target volume (PTV) and organs at risk (OARs). The second aim was to estimate the projected relative risk of radiation-induced secondary cancers for hybrid techniques.
UNASSIGNED: Three treatment plans were prepared in 3D-CRT, h-IMRT, and h-VMAT techniques for each of the 40 patients, who underwent CT simulation in deep inspiration breath-hold (DIBH). For hybrid techniques, plans were created by combining 3D-CRT and dynamic fields with an 80%/20% dose ratio for 3D-CRT and IMRT or VMAT. Cumulative dose-volume histograms were used to compare dose distributions within the PTV and OARs (heart, left anterior descending coronary artery [LAD], left and right lung [LL, RL], right breast [RB]). Projected risk ratios for secondary cancers were estimated relative to 3D-CRT using the organ equivalent dose (OED) concept for the Schneider\'s linear exponential, plateau, and full mechanistic dose-response model.
UNASSIGNED: All plans fulfilled the PTV criterium: V95%≥95%. Compared to 3D-CRT, both hybrid techniques showed significantly better target coverage (PTV: V95%>98%, p < 0.001), and the best conformality was achieved by h-ARC plans (CI: 1.18 ± 0.09, p < 0.001). Compared to 3D-CRT and h-ARC, h-IMRT increased the average sum of monitor units (MU) over 129.9% (p < 0.001). H-ARC increased the mean dose of contralateral organs and the LL V5Gy parameter (p < 0.001). Both hybrid techniques significantly reduced the Dmax of the heart by 5 Gy. Compared to h-IMRT, h-ARC increased secondary cancer projected relative risk ratios for LL, RL, and RB by 18, 152, and 81%, respectively.
UNASSIGNED: The results confirmed that both hybrid techniques provide better target quality and OARs sparing than 3D-CRT. Hybrid VMAT delivers less MU compared to hybrid IMRT but may increase the risk of radiation-induced secondary malignancies.