螺旋断层调强放疗治疗纵膈淋巴瘤患者的效果及剂量学比较

Effect and dosimetry comparison of helical tomotherapy in the treatment of patients with mediastinal lymphomas

目的比较螺旋断层调强放疗(HT)和常规加速器调强适形放射治疗(IMRT)治疗纵膈淋巴瘤患者的效果及剂量学特点。方法选择接受纵膈区域放疗的淋巴瘤患者65例,根据放疗方案不同分为HT组(28例)和IMRT组(37例)。比较两组患者的治疗疗效及不良反应,根据最低剂量(D_(min))、最高剂量(D_(max))、平均剂量(D_(mean))、靶区内超过95%处方剂量的相对体积(V_(95%))、靶区内超过105%处方剂量的相对体积(V_(105%))、适形度指数(CI)和靶区均匀指数(HI)评价靶区照射情况,利用剂量体积直方图评价周围危及器官(OAR)照射剂量。结果两组疗效缓解率比较,差异无统计学意义(χ^(2) =0.01,P>0.05),但HT组不良反应发生率明显低于IMRT组,差异有统计学意义(χ^(2) =4.82,P<0.05);HT组的D_(min)和V_(95%)明显低于IMRT组,CI值更接近于1,差异均有统计学意义(t分别=7.44、6.90、2.49,P均<0.05);HT组双肺D_(mean)、V_(5)、V_(20),食管D_(mean),心脏V_(30)及脊髓D_(50)明显低于IMRT组,但左侧乳腺D_(max)、D_(mean)、V_(4)、V_(20)和右侧乳腺D_(max)、D_(mean)、V_(4)、V_(20)明显高于IMRT组,差异均有统计学意义(t分别=4.75、5.45、3.31、4.06、3.48、3.02、7.00、7.95、11.49、12.30、11.67、8.71、12.54、10.22,P均<0.05)。结论HT放疗方案可为纵膈淋巴瘤患者提供贴近靶区的适形度较好的剂量分布,降低不良反应发生率,保护周围正常组织,但可能会增加乳腺低剂量体积,需根据不同患者的情况选择放疗方案。

Objective To compare the effects and dosimetric characteristics of helical tomotherapy(HT)radiotherapy and conventional intensity modulated radioation therapy(IMRT)in the treatment of patients with mediastinal lymphomas.Methods Totally 65 patients with lymphomas who underwent radiotherapy in mediastinal region were selected and divided into HT group(28 cases)and IMRT group(37 cases)according to different radiotherapy regimens.Curative effect and adverse reactions were compared between the two groups.The minimum dose(D_(min)),maximum dose(D_(max)),mean dose(D_(mean)),target volume fraction receiving over 95%of the prescribed dose(V_(95%)),target volume fraction receiving over 105%of the prescribed dose(V_(105%)),conformity index(CI)and homogeneity index(HI)were used to evaluate irradiation in target region.OAR irradiation dose was evaluated with the dose-volume histogram.Results There was no statistically significant difference in remission rates between the two groups(χ^(2) =0.01,P>0.05),but the incidence of adverse reactions in HT group waslower than that in IMRT group(χ^(2) =4.82,P<0.05).The D_(min) and V_(95%)of HT group were lower than those of IMRT group,and the CI value was closer to 1(t=7.44,6.90,2.49,P<0.05).The D_(mean),V_(5) and V_(20) of bilateral lungs,esophageal D_(mean),cardiac V_(30) and spinal D_(50) in HT group were significantly lower than those in IMRT group,while D_(max),D_(mean),V_(4) and V_(20) of left breast,D_(max),D_(mean),V_(4) and V_(20) of right breast were higher than those in IMRT group(t=4.75,5.45,3.31,4.06,3.48,3.02,7.00,7.95,11.49,12.30,11.67,8.71,12.54,10.22,P<0.05).Conclusion HT radiotherapy can provide mediastinal lymphoma patients with good-conformity dose distribution close to the target volume,reduce the incidence of toxic and side effects,and protect surrounding normal tissues.However,it may increase the low-dose volume of mammary gland.Therefore,the radiotherapy regimen should be selected based on patients’conditions.