非共面野在植入式心脏起搏器食管癌调强放疗中的应用

通过对非共面野调强(Non-coplanar intensity modulated radiation therapy,No-co-IMRT)与共面野调强(Coplanar IMRT,Co-IMRT)的比较,探讨非共面野在植入式心脏起搏器食管癌调强放疗中的剂量学特点。选取8例经临床病理检查证实并均带有植入式心脏起搏器的食管癌患者,采用Eclipse逆向调强计划系统,对每例患者分别设计非共面野调强计划(3个共面野和2个非共面野)和共面野调强计划(5个共面野)。每例患者的2个计划所用物理参数一致,并用剂量体积直方图(DVH)、适形指数(CI)、均匀指数(HI)和机器跳数和控制点数目等项目作为计划评价指标。结果显示,除非共面野计划中的起搏器和导线Dmax指标明显降低外,两组计划中靶区和其他正常组织间的差异均无统计学差异(p0.05)。与共面调强放疗计划相比,非共面调强计划中的机器跳数和控制点数也没有明显增加。结果表明在对有植入式心脏起搏器的食管癌放疗中,采用非共面调强技术能显著降低心脏起搏器和导线的受量。

Study on non-coplanar intensity modulated radiation therapy in esophageal carcinoma implanted with permanent cardiac pacemaker

The aim is to evaluate the physical dose distributions in esophageal carcinoma implanted with permanent cardiac pacemaker treated with non-coplanar intensity modulated radiation therapy （no-co-IMRT）. Eight patients with esophageal carcinoma implanted cardiac pacemaker proven by histology were treated by IMRT. For each patient, we designed two IMRT plans by Eclipse IMRT inverse plan system： non-coplanar IMRT plan （3 coplanar fields and 2 non-coplanar fields） and coplanar IMRT plan （5 coplanar fields）. The same physical parameter was applied to the same patient in both plans. Plans were evaluated in terms of dose-volume histogram, conformity index, homogeneity index, monitor unit and control points. The results showed that no-co-IMRT plan could significantly reduce the max dose of implantable cardiac pacemaker and the wires （p〈0.05）, but no significant difference was found between no-co-IMRT plan and co-IMRT plan in target volume and other normal tissues Compared with co-IMRT plan, the monitor unit （MU） and control points of no-co-IMRT plan were not increased significantly （p〉0.05）. These findings indicate that the technique of no-co-IMRT can obtain the fewer max dose of implantable cardiac pacemaker and the wires during intensity modulated radiation therapy of esophageal carcinoma.