断层径照技术在中下段食管癌放射治疗中的应用

Application of Tomo Direct in the radiotherapy for esophageal carcinoma of mid-lower part

目的:分析比较断层径照调强技术(TD)与调强放射治疗(IMRT)技术治疗中下段食管癌的剂量学差异,评估TD治疗中下段食管癌的可行性。方法:回顾性选取10例中下段食管癌患者,处方剂量为肿瘤靶区计划肿瘤体积(PGTV)给予63 Gy/30次,预防照射区计划靶区(PTV)给予54 Gy/30次。10例患者均按原各自IMRT计划照射野角度重新设计TD计划,评估两种计划靶区以及危及器官剂量参数,比较治疗时间和机器跳数的差异。结果:TD计划靶区PGTV的D_(mean)、D_2及靶区剂量均匀度指数(HI)优于IMRT计划,且差异有统计学意义(t=-2.737,t=-3.471,t=-3.709;P<0.05)。TD计划的双肺受量均低于IMRT计划,其中V_(10)、V_(20)及V_(30)均有统计学差异(t=-2.165,t=-3.40,t=-4.114;P<0.05)。脊髓和心脏受量均无统计学差异。在实施效率上,TD治疗时间略长于IMRT。结论:相同照射野时TD技术对肺的保护要明显优于IMRT技术,但是治疗时间稍长,可以作为临床应用的选择。

Objective： To compare and analyze dosimetric differences between tomo direct（TD） and intensity modulated radiation therapy（IMRT） in the treatment for esophageal carcinoma of middle and lower part, and evaluate the feasibility of TD in the treatment. Methods： 10 patients with esophageal carcinoma of middle and lower part were enrolled in this retrospective study. The prescription dose was 63 Gy/30 F for planned gross target volume（PGTV）, and 54 Gy/30 F for planned target volume（PTV）. All of 10 patients were redesigned in TD plan as original radiation angle of IMRT plan apiece, and two kinds of planning target region and dose parameter of organ at risk（OAR） were evaluated, and the differences of treatment time and monitor unit（MU） also were compared, respectively. Results： For PGTV, the D（mean）, D2 and homogeneity index（HI） of TD plans were significantly better than those of IMRT plans（t=-2.737, t=-3.471, t=-3.709, P〈0.05）. The received doses of double lung of TD plan were lower than that of IMPT plan, and the differences of V（10）, V（20） and V（30） between the TD plan and IMRT plan were statistically significant（t=-2.165, t=-3.40, t=-4.114, P〈0.05）. While the received dose of spinal cord and heart between them were not significant. In the implement efficiency, the treatment time of TD plan was longer than that of IMRT plan. Conclusion： The preventive effect for lung of TD plan is obviously superior to IMRT plan when the same radiation field is chosen. Although treatment time of TD plan is longer, it still is a recommendable choice in clinical application.