螺旋断层放疗在胸中下段食管癌治疗中对心脏功能保护的研究

【摘要】目的:对比胸中下段食管癌螺旋断层放疗和适形调强放疗心脏的剂量分布，分析螺旋断层放疗前后的心肌酶谱，评估螺旋断层放疗在食管癌治疗中对心脏功能的保护作用。方法:筛选37例胸中下段食管鳞癌患者，为每位患者制定适形调强放疗和螺旋断层放疗计划，比较两种放疗方式的计划靶区（PTV）、心脏的剂量学参数。同时在螺旋断层放疗前一周及一周后进行心肌酶谱检查，并对放疗心肌酶谱进行对比分析。结果:螺旋断层放疗的PTV与心脏最大剂量，心脏V20、V30、V40、V50、V60均明显低于适形调强放疗，差异有统计学意义（P<0.05）；两种放疗方式的PTV适形度指数差异有统计学意义（P<0.05），而PTV均匀性指数、TOMO前后心肌酶谱差异无统计学意义（P>0.05）。结论:螺旋断层放疗在靶区剂量分布优于适形调强放疗的条件下，能显著降低心脏的最大剂量，并且引起的早期心肌损伤不明显，对心脏起到更好的保护作用。

Protection of cardiac function in tomotherapy for middle and lower thoracic esophageal carcinoma

Abstract: Objective To compare the dose distribuction in the heart between tomotherapy (TOMO) and intensity-modulated radiotherapy (IMRT) for middle and lower thoracic esophageal carcinoma, and to analyze the myocardial enzymogram before and after TOMO, thereby evaluating the protective effect of TOMO for esophagus carcinoma on cardiac function. Methods A total of 37 patients with middle and lower thoracic esophageal squamous cell carcinoma were enrolled in the study. Both IMRT and TOMO plans were designed for each patient, and the dosimetric parameters of planning target volume (PTV) and the heart were compared between two radiotherapy strategies. Meanwhile, myocardial enzymes spectroscopy was performed one week before and after TOMO for comparing the changes in myocardial enzymogram. Results The maximum doses to PTV and the heart in TOMO were significantly lower than those in IMRT (P<0.05), and the V20, V30, V40, V50, V60 of the heart was significantly smaller in TOMO (P<0.05). There was significant difference between two radiotherapy strategies in the conformity indexs of PTV (P<0.05), but not in the the homogeneity index of PTV. Moreover, no significant difference was found in myocardial enzymogram before and after TOMO (P>0.05). Conclusion Under the condition that TOMO has a better dose distribution in the target area than IMRT, TOMO can significantly reduce the maximum dose to the heart, and the induced early myocardial injury is not obvious. Therefore, TOMO plays a better protection for the heart.