胸中段食管癌三维适形放疗与简化调强放疗技术的剂量学比较

目的：评估三维适形放疗与简化调强放疗两种不同放疗技术在胸中段食管癌放射治疗中的优缺点。方法20例胸中段食管癌患者分别进行3DCRT和sIMRT两种放疗计划设计，处方剂量均为66 Gy/33 f。比较两组计划的靶区与危及器官剂量学参数及加速器跳数（ MU）。结果 sIMRT在PTV的剂量覆盖、均一性及适形度均优于3DCRT（P＜0．05）；3DCRT与sIMRT的双肺V30 Gy及双肺V20 Gy分别为11．61±3．68 vs．10．33±3．02（P＝0．010）和23．37±8．38 vs．18．89±4．45（P＝0．001）。两组的双肺V5 Gy无显著性差异。3DCRT与sIMRT的MU分别为542．24±76．32和530．80±97．13（P＝0．677）。结论与3DCRT相比，sIMRT有较满意的PTV高剂量覆盖及均匀的剂量分布。在危及器官保护方面，sIM-RT的双肺高剂量区范围明显低于3DCRT。两组计划的MU无显著性差异。

Dosimetric comparison of three dimensional conformal radiotherapy and simplified intensity modulated radiotherapy for middle-third esophageal cancer

Objective To compare the dose distribution between three dimensional conformal radiothera -py（3DCRT） and simplified intensity modulated radiotherapy （ sIMRT） for middle-third esopheagal cancer .Meth-ods Twenty middle-third esopheagal cancer patients were enrolled in this study .Dosimetric values for sIMRT and 3DCRT were calculated for total dose of 66 Gy using 2 Gy/day.The parameters included the conformal index （CI）,homogeneity index（HI）,mean dose and hot spot（V105%）for the planned target volume（PTV）as well as the monitor units（MUs）for plan efficiency,the mean dose（Dmean）for the organs at risk（OAR）.The percentage of the normal lung volume receiving≥30,＆gt;20 and ＆gt;5 Gy（V30 Gy,V20 Gy and V5 Gy）were evaluated to deter-mine lung toxity.Results sIMRT achieved significant better Dmin ,Dmean,V105%,HI,CI and spinal cord than 3DCRT（P〈0.05）.The normal lung V30 Gy and V20 Gy of 3DCRT and sIMRT were 11.61 ±3.68 vs.10.33 ± 3.02（P=0.010）and 23.37 ±8.38 vs.18.89 ±4.45（P=0.001）,respectively.Comparable sparing of normal tissue including heart and the normal lung V 5 Gy with both two plans .The number of MU was 542 .24 ±76 .32 for 3DCRT and 530.8 ±97.13 for sIMRT（P=0.677）.Conclusion sIMRT provides favorable tumor coverage , homogeneity and conformity and can get better normal lung sparing than 3DCRT.However sIMRT is not superior to 3DCRT in terms of treatment efficiency .