中段食管癌序贯加量调强放疗与同步加量调强放疗的剂量学分析

目的 比较常规调强放疗与同步加量调强放疗的剂量学参数的差异。 方法 选择10例中段食管癌的患者,分别在计划系统上制定序贯加量调强放疗计划(SB-IMRT)和同步加量调强放疗计划(SIB-IMRT)。SB-IMRT是先给计划靶区(PTV)50 Gy/25F,然后在大体肿瘤区(GTV)推量10 Gy/5F,SIB-IMRT是PTV 区50 Gy/28F,同时给予GTV区60 Gy/28F。采用配对t检验方法比较两种计划的剂量学参数。 结果 SIB-IMRT的适形指数CI(0.59±0.30)优于SB-IMRT(0.59±0.30)(P=0.000),但两者均匀指数HI差异无统计学意义(P=0.105)。SIB-IMRT的右肺的V₂₀、V₃₀、平均剂量(MLD),左肺的MLD以及心脏的V₅₀均低于SB-IMRT(统计值分别为P=0.012、P=0.007、P=0.002、P=0.001、P=0.003),两者在左肺的V₂₀、V₃₀以及脊髓最大受量差异无统计学意义(统计值分别为P=0.053、P=0.134、P=0.998)。 结论 在总物理剂量相同的情况下,相比序贯加量调强放疗,同步加量调强放疗的适形性更优,并且能减少部分危及器官的受量,尤其对肺脏和心脏的保护更有优势。

A dosimetric study of sequential boost intensity-modulated radiotherapy and simultaneously integrated boost intensity-modulated radiotherapy in midpiece esophageal carcinoma

Objective To compare the differences in dosimetric parameter between sequential boost intensity-modulated radiotherapy(SB-IMRT) with simultaneously integrated boost intensity-modulated radiotherapy (SIB-IMRT) for midpiece esophageal carcinoma. Methods Ten patients with midpiece esophageal carcinoma were selected and treated with (SB-IMRT and SIB-IMRT).In SB plan the planned target area (PTV) was given 50 Gy/25F,and then the gross tumor volume (GTV) had an extra boost of 10 Gy/5F.The PTV was given 50 Gy/28F and simultaneously the GTV was given 60 Gy/28F in SIB plan.The differences in dosimetric parameter between SB-IMRT and SIB-IMRT were compared by using paired-samples t test. Results The conformal index (CI) of SIB-IMRT(0.59±0.30) was superior to that of SB-IMRT(0.59±0.30)(P=0.000),but the difference in homogeneity index (HI) was not statistically significant (P=0.105).The V₂₀,V₃₀ and mean lung dose (MLD) of the right lung,MLD of the left lung,and V₅₀ of the heart in SIB-IMRT plan were lower than those in SB-IMRT plan (P=0.012;P=0.007;P=0.002;P=0.001 and P=0.003,respectively),but the V₂₀,V₃₀ of the left lung and the maximum dose of spinal cord were not significantly different(P=0.053;P=0.134 and P=0.998,respectively). Conclusions On the condition of the same amount of physical dose,compared with SB-IMRT,the SIB-IMRT has better conformability and can efficiently reduce the risk of partial damage to organs especially for the lung and the heart.