食管癌常规放疗与三维适形放疗剂量分布的比较

目的比较食管癌常规三野照射和三维适形放射治疗2种不同的治疗方法,不同设野方法的计划中靶区及正常组织的受量。方法应用三维治疗计划系统(TPS)在28例食管癌患者的CT虚拟图像上分别设计2种外照射计划(A:常规三野;B:三维适形三野),应用剂量体积直方图比较2种计划肺、心脏等正常组织受量及肺正常组织并发症发生概率(NTCP)的区别。根据肺的NTCP来估计放射性肺炎的发生概率。结果常规三野照射和适形放射治疗的比较:PTV各项指标无显著性差异,心脏受照的体积百分比(V40、V50)及左右肺及双肺受照的体积百分比(V20、V30)等有明显的差异(P=0)。结论食管癌三野常规照射与适形放射治疗比较:三野的适形放射治疗有利于保护心脏及正常肺组织,可降低放射性肺炎的发生概率。

Dosimetric Comparison between Conventional and Three Dimensional Conformal Radiation Therapy for Esophageal Carcinoma

Objective To compare the dose distribution in the planning target volume (PTV) and organs at risk of conventional and 3-dimentional radiotherapy (3DCRT) in treating esophageal carcinoma.Methods 3 field conventional radiotherapy and 3DCRT treatment planning were performed in the 3-D treatment planning system for 28 patients with esophageal carcinoma.Dose volume histogram (DVH) was used to compare the dose distribution in the PTV,lungs and heart of the two techniques.Normal tissue complication possibility (NTCP) was used to evaluate the possibilities of radiation induced pneumonitis.Results There was no significant difference of the two techniques in terms of the dose coverage of PTV.The volume of heart receiving at least 40 Gy (V40) and 50 Gy (V50),and the volume of both lungs receiving at least 20 Gy (V20) and 30 Gy (V30) were significantly different by the two techniques.Conclusion Compared to the conventional radiotherapy technique,3DCRT could reduce the dose to the heart and lungs,and decrease the radiation induced pneumonitis possibilities.