左乳癌根治术后sIMRT和VMAT对对侧乳腺和对侧肺的剂量学研究

Dosimetric study of contralateral breast and contralateral lung with sIMRT and VMAT after radical resection of left breast cancer

目的探讨左乳癌根治术后静态调强放射治疗(sIMRT)和容积旋转调强放射治疗技术(VMAT)对对侧乳腺和对侧肺的剂量学特点。方法选取2017年7月至2020年1月于我院行左乳癌根治术的患者25例。采用Pinnacle310.0治疗计划系统分别设计sIMRT和VMAT两组计划,比较两种计划的剂量学参数。结果VMAT的靶区CI明显高于sIMRT,VMAT的靶区HI明显低于sIMRT,差异具有统计学意义(P<0.05)。VMAT左肺的V5、V10、V20、Dmean和心脏的V30、V40、Dmean均明显低于sIMRT,差异具有统计学意义(P<0.05)。VMAT对侧乳腺的V5、V10、V15和Dmean均明显高于sIMRT,差异具有统计学意义(P<0.05)。VMAT对侧肺的V5、V10、V15、V20和Dmean均明显高于sIMRT,差异具有统计学意义(P<0.05)。结论左乳癌根治术后患者行sIMRT和VMAT靶区、心脏和左肺剂量均能满足临床要求,整体上VMAT优于sIMRT。但对侧乳腺和对侧肺组织的剂量VMAT明显高于sIMRT,尤其是低剂量体积V5、V10明显增大,故在左乳腺癌根治术后行VMAT应关注对侧乳腺和对侧肺组织的低剂量损伤。

Objective To investigate the dosimetric characteristics of contralateral breast and contralateral lung with static intensity modulated radiotherapy(sIMRT)and volumetric modulated arc therapy(VMAT)after radical resection of left breast cancer.Methods A total of 25 patients with left breast cancer after radical mastectomy in our hospital from July 2017 to January 2020 were selected.The Pinnacle310.0 treatment planning system was used to design sIMRT and VMAT two plans respectively,and the dosimetry parameters of the two plans were compared.Results The CI of VMAT was significantly higher than that of sIMRT,the HI of VMAT was significantly lower than that of sIMRT,and the differences were statistically significant(P<0.05).The V5,V10,V20,Dmean of VMAT left lung and V30,V40 and Dmean of VMAT heart were significantly lower than those of sIMRT,and the differences were statistically significant(P<0.05).The V5,V10,V15 and Dmean of VMAT contralateral breast were significantly higher than those of sIMRT,and the differences were statistically significant(P<0.05).The V5,V10,V15 and Dmean of VMAT contralateral lung were significantly higher than those of sIMRT,and the differences were statistically significant(P<0.05).Conclusion The target dose,heart dose and left lung dose of sIMRT and VMAT in patients with left breast cancer after radical mastectomy can meet the clinical requirements,and VMAT is superior to sIMRT on the whole.However,the dose of VMAT in contralateral breast and contralateral lung tissue is significantly higher than that in sIMRT,especially the low-dose volume V5 and V10 increase significantly.Therefore,the low-dose injury of contralateral breast and contralateral lung tissue should be paid attention to when VMAT is performed after left breast cancer radical operation.