双肺中央型非小细胞肺癌两种调强放射治疗计划的剂量学比较

Dosimetric Comparison of Two Intensity-Modulated Plans in the Whole Lung of Central Non-Small Cell Lung Cancer

目的比较双肺中央型非小细胞肺癌(NSCLC)在静态调强放射治疗(sIMRT)和容积旋转调强放射治疗(VMAT)两种治疗方式下的剂量学差别,为临床放疗计划设计提供依据。方法选取28例NSCLC患者作为对象,分别设计sIMRT和VMAT两种计划。计划靶区(PTV)PTV-G处方剂量设定为60 Gy/30 F,PTV-C处方剂量设定为54 Gy/30 F。采用剂量体积直方图(DVH)比较每种计划的靶区和危及器官剂量差异,采用配对t检验分析结果。结果无论中央型NSCLC位于左侧肺还是右侧肺,所设计的两种计划在靶区覆盖率上相当,且VMAT计划的靶区均匀性、适形度、D_(95)(D_(X)为X%靶区体积所接受的剂量)优于sIMRT(P<0.05);VMAT计划在脊髓D_(max)、全肺的V_(20)(V^(X)为X Gy等剂量线包绕的总的肺组织体积占肺总体积的百分比)、左肺V_(20)和右肺V_(20)方面,保护得更好;VMAT计划在右侧中央型NSCLC全肺V_(20)、右肺V_(20)、V_(30)、D_(mean)方面,保护得更好;VMAT计划在左侧中央型NSCLC全肺V_(5)、左肺V_(30)、D_(mean)和右肺V_(5)、D_(mean)方面,保护得更好,差别均有统计学意义(P<0.05)。结论VMAT计划优于sIMRT计划,在部分危及器官保护方面,VMAT计划较有优势;但对于不同位置而言,应综合考虑肺V_(5)及其他危及器官受量选择放疗方式。

Objective To investigate the whole lung of central non-small cell lung cancer(NSCLC)under statics intensity-modulated radiotherapy(sIMRT)and volumetric modulated arc therapy(VMAT)techniques,and to provide a basis for the planning and design of clinical radiotherapy.MethodsA total of 28 patients with central non-small cell lung cancer in our hospital were selected,and sIMRT and VMAT plans were designed respectively.The prescription of planning target volume(PTV)PTV-G dose was 60 Gy/30 F,the prescription of PTV-C dose was 54 Gy/30 F.The dose volume histograms(DVH)were used to compare the dose differences between PTV and organs at risk for each plan and the results were analyzed by paired t-test.Results The two plans of central NSCLC whether central NSCLC was located on the left or right lung had similar target coverage index,and VMAT plan had better target conformity index,homogeneity index and D_(95) than sIMRT plan.VMAT plan had better protection in spinal D_(max),whole lung V_(20),left lung V_(20) and right lung V_(20).When the central NSCLC was located in the right,VMAT plan was better in the whole lung V_(20),right lung V_(20),V_(30) and D_(mean).When the central NSCLC was located in the left,VMAT plan had better protection in terms of whole lung V_(5),left lung V_(30) and D_(mean),and right lung V_(5) and D_(mean),with statistical significance.Conclusion VMAT plan is generally superior to sIMRT plan,and VMAT plan has advantages in the protection of some organs at risk.However,in terms of different locations,the dose of lung V_(5) and other organs at risk should be considered to select the radiotherapy method.