腹式深吸气屏气和自由呼吸对左侧乳腺癌保乳术和改良根治术后调强放疗的剂量学影响

Dosimetric effects of ADIBH and FB on intensity modulated radiation therapy for left breast cancer after breast conserving surgery and modified radical surgery

目的探讨两种呼吸技术[腹式深吸气屏气(ADIBH)和自由呼吸(FB)]对左侧乳腺癌保乳术和改良根治术后调强放疗(IMRT)的剂量学影响。方法50例左侧乳腺癌术后需行IMRT的患者中,行保乳术者30例,行改良根治术者20例。采集ADIBH和FB下患者的CT定位图像,行IMRT计划设计,比较两种呼吸技术中计划靶区(PTV)参数[平均剂量(D_(mean))、均匀指数、适形指数]和危及器官(OAR)剂量参数[心脏接受40、30、20Gy照射的体积百分比(V_(40)、V_(30)、V_(20))及平均剂量(D_(mean)),冠状动脉左前降支(LAD)V30、V_(20)、D_(mean),左肺V_(30)、V_(20)、D_(mean)]。比较保乳术和改良根治术患者ADIBH与FB的OAR剂量参数差值。结果保乳术和改良根治术患者ADIBH与FB中PTV参数D_(mean)、均匀指数和适形指数比较差异均无统计学意义(P>0.05);但ADIBH时的LAD(D_(mean)、V_(20)、V_(30))、心脏(D_(mean)、V_(20)、V_(30)、V_(40))和左肺(D_(mean)、V_(20)、V_(30))剂量参数低于FB(P<0.05)。与改良根治术相比,LADV_(20)差值在保乳术患者中变化更大(P<0.05)。保乳术和改良根治术患者中,LAD D_(mean)差值均大于心脏D_(mean)差值(P<0.05)。结论无论是保乳术还是改良根治术,ADIBH都可以降低左侧乳腺癌术后IMRT患者心脏、LAD及左肺的辐射剂量,起到保护心肺的作用。

Objective To investigate the dosimetric effects of two respiratory techniques[abdominal deep inspiration breath holding(ADIBH)and free breathing(FB)]on the intensity modulated radiation therapy(IMRT)for left breast cancer after breast conserving surgery and modified radical surgery.Methods ADIBH and FB during IMRT were performed in 50 patients with left breast cancer after breast conserving surgery(30 cases)or modified radical surgery(20 cases).The CT positioning images of the patients were collected,and IMRT planning was performed.The parameters of planned target area(PTV)[mean dose(D_(mean)),homogeneity index(HI),conformity index(CI)],and organ at risk(OAR)[volume percentage of the heart receiving 40,30,20 Gy radiation(V_(40),V_(30),V_(20))and D_(mean),left anterior descending coronary artery(LAD D_(mean),V_(30),V_(20))and the left lung(D_(mean),V_(30),V_(20))]underwent the two respiratory techniques were compared.The difference in OAR dose parameters between ADIBH and FB was compared between the patients underwent breast conserving surgery and those underwent modified radical surgery.Results For the patients underwent breast conserving surgery and modified radical surgery,there were no significant differences in PTV parameters(D_(mean),HI and CI)between ADIBH and FB(P>0.05).Dosimetric parameters of LAD(D_(mean),V_(20),V_(30)),the heart(D_(mean),V_(20),V_(30),V_(40))and the left lung(D_(mean),V_(20),V_(30))underwent ADIBH were significantly lower than those underwent FB(P<0.05).Compared with the modified radical surgery,the difference of LAD V_(20)in the patients with breast conserving surgery was changed more(P<0.05).The difference of LAD Dmean was greater than that of heart D_(mean)in the patients underwent breast conserving surgery and modified radical surgery(P<0.05).Conclusion ADIBH can reduce the radiation doses of the heart,LAD and left lung and play a role in protecting the heart and lung,in IMRT patients after left breast cancer surgery,regardless of breast conserving surgery or modified radical surgery.