中段食管癌调强放疗照射野数对正常组织受量的影响

Normal tissue dose affected by IMRT with intensity-modulated radiation fields in middle esophageal cancer

目的比较中段食管癌3种不同调强放疗照射野数对危及器官的剂量分布差异。方法10例患者分别勾画靶区和危及器官,均设计3野、5野、7野3种调强放疗计划,比较3个计划危及器官的剂量学差异。结果3种调强适形计划中脊髓受照射的最大剂量和心脏的剂量体积参数比较,差异无统计学意义(P>0.05);心脏V50和V20差异均无统计学意义(P>0.05);左、右肺V5对比有显著性差异(P<0.05);3野与7野在左、右肺V30均有统计学意义(P<0.05),3者在右肺V10统计学上均有显著性差异(P<0.05)。结论中段食管癌3野、5野、7野3种计划均能保证脊髓和心脏受量在最大耐受剂量以内,3野可明显减少低剂量受照体积,而7野可减少高剂量受照体积。

Objective Comparison of dose distribution of three different intensity-modulated radiotherapy(IMRT)fields in the middle esophageal cancer for organs at risk.Methods Ten patients were delineated with target area and endangered organs.And were designed with 3 fields,5 fields,and 7 fields,to compare the dosimetric differences between the three planned organs.Results There was no significant difference in the maximum dose of spinal cord irradiation(P>0.05).There were no significant differences in heart V50 and V20(P>0.05).There were significant differences in V5 contrast between left and right lungs(P<0.05).There were significant differences between the 3 and 7 wild in the left and right lungs(P<0.05).There were significant differences in V10 statistics between the three groups(P<0.05).Conclusion 3-field,5-field,and 7-field can ensure that the spinal cord and heart dose are within the maximum tolerated dose.3-field can significantly reduce the volume of low-dose exposure,while 7-field can reduce the volume of high-dose exposure.