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[目的]分析食管中段癌三维适形放疗(3D-CRT)和旋转拉弧适形放疗(Rapid Arc-SBRT)2种放疗技术的剂量学特点。[方法]收集9例食管中段癌放疗患者,分别设计3D-CRT和Rapid Arc-SBRT放疗计划;绘制出PTV的DVH示意图;比较各计划靶区适形指数(CI)、均匀指数(HI)以及机器跳数(MU);计算双肺的V5、V20及平均受量Dmean,脊髓最大受量,比较两种照射方式的优劣。[结果 ]3DCRT的CI值为0.61±0.04,HI为1.12±0.05,最大剂量(6872±528)c Gy,机器跳数289±11,左肺V5为56.2%±18.9%,V20为26.3%±6.1%,Dmean为(1203±272)c Gy,右肺V5为58.3%±14.0%,V20为24.8%±7.2%,Dmean为(1191±399)c Gy,脊髓为(2463±1399)c Gy。Rapid ArcSBRT的CI值为0.65±0.05,HI为1.10±0.04,最大剂量(6691±522)c Gy,机器跳数292±15,左肺V5为69.8%±24.8%,V20为15.0%±12.6%,Dmean为(1155±467)c Gy,右肺V5为70.2%±22.4%,V20为13.2%±14.4%,Dmean为(1130±574)c Gy,脊髓为(3553±652)c Gy。[结论]Rapid Arc-SBRT剂量分布、靶区适形度、剂量均匀性要优于3DCRT。
[Objective] To analyze the dosimetric characteristics of two kinds of radiotherapy techniques in three-dimensional conformal radiotherapy (3D-CRT) and rapid arc-SBRT in the middle esophagus. [Methods] Nine patients with esophageal cancer undergoing radiotherapy were enrolled. 3D-CRT and Rapid Arc-SBRT radiotherapy plans were designed respectively. A DVH diagram of PTV was drawn. The CIs, Homogeneity Index (HI) Machine hop count (MU); calculated V5, V20 of the lungs and the average dose of Dmean, the maximum amount of spinal cord to compare the pros and cons of the two irradiation methods. [Results] The CI value of 3DCRT was 0.61 ± 0.04, the HI was 1.12 ± 0.05, the maximum dose (6872 ± 528) c Gy, the machine hops 289 ± 11, the left lung V5 was 56.2% ± 18.9% and the V20 was 26.3% ± Dmean was (1203 ± 272) c Gy, right V5 was 58.3% ± 14.0%, V20 was 24.8% ± 7.2%, Dmean was (1191 ± 399) c Gy and spinal cord was (2463 ± 1399) c Gy . Rapid ArcSBRT had a CI of 0.65 ± 0.05, a HI of 1.10 ± 0.04, a maximum dose of 6691 ± 522 c Gy, a machine hops of 292 ± 15, left lung V5 of 69.8% ± 24.8% and V20 of 15.0% ± 12.6% , Dmean was (1155 ± 467) c Gy, right lung V5 was 70.2% ± 22.4%, V20 was 13.2% ± 14.4%, Dmean was (1130 ± 574) c Gy and spinal cord was (3553 ± 652) c Gy. [Conclusion] The dose distribution, target conformality and dose uniformity of Rapid Arc-SBRT are superior to 3DCRT.