调强放疗与传统放疗在胸段食管癌放射治疗中的应用

Application of intensity-modulated and conventional radiotherapy for thoracic esophageal cancer

目的评价调强放疗(IMRT)与传统放疗(BOX)在胸段食管癌放射治疗中的临床应用效果。方法 22例食管癌患者分别采用IMRT与BOX进行放射治疗,比较IMRT和BOX在胸段食管癌放疗中应用时在靶区适形度以及危及器官受照射剂量方面的疗效。结果 IMRT和BOX的靶区覆盖分别为(95.61±0.60)%和(95.49±0.42)%。IMRT的适形指数为0.85±0.04,高于BOX的0.78±0.03(P<0.01);而IMRT均匀指数为0.89±0.01,低于BOX的0.91±0.01(P<0.01)。IMRT减少了20Gy剂量所覆盖的肺体积(V20)和肺平均剂量,却增加了5Gy剂量所覆盖的肺体积(V5);IMRT同时减少了心脏和脊髓的受照射剂量。结论 IMRT在获得较高靶区适形度的同时能很好地保护心脏、肺、脊髓等危及器官,但应注意肺低剂量受照射区域的增加。

Objective To evaluate the efficacy of intensity-modulated radiotherapy（IMRT） and conventional radiation therapy （BOX） in thoracic esophageal cancer radiotherapy. Methods The radiotherapy with IMRT and BOX techniques was performed in 22 patients with thoracic esophageal cancer. The dosimetric results were compared. Results The PTV coverage percentages of IMRT and the BOX were （95.61 ± 0. 60） % and （95.49± 0. 42） %, respectively. The comformity index（CI） of IMRT was better than that of BOX（0. 85±0. 04 vs. 0. 78±0. 03） （P〈0. 01） ,but the homogeneous index（HI） was lower than that of BOX（0. 89± 0. 01 vs. 0. 91 ± 0. 01） （P〈0. 01）. With IMRT, the lung volume covered by 20 Gy（V20） radiation and the mean dose of the lungs were decreased, but the lung volume covered by 5 Gy（V5） radiation was increased. The radiation doses received by the heart and spine cords in IMRT were lower than those in BOX. Conclusion The IMRT improves the comformity idex and gives better lung sparing as well as the heart and the spine cords, but attention should be paid to the increase of area where received low radiation dose.