IMRT与3D-CRT在中央型非小细胞肺癌中的剂量分布研究

将三维适形放疗(3D-CRT)和调强放疗(IMRT)应用于中央型非小细胞肺癌的放射治疗中,并评价了不同计划方案在剂量学上的差异性。本研究选择了32例II期中央型非小细胞肺癌患者,在CT图像的基础上,对每位患者分别做了1个3D-CRT和2个IMRT计划(5野和7野),并评价计划的剂量分布特点及其优势。结果发现,IMRT的靶区平均剂量(PTVDmean)和靶区最大剂量(PTVDmax),靶区最大剂量与处方剂量的百分比(PTVDmax(%))和靶区适形指数(CI)均比3D-CRT高,但靶区均匀指数(HI)较3D-CRT差。IMRT计划中各项肺的指标和1%体积的脊髓所接受的剂量(脊髓D01)低于3D-CRT的对应值。另5野和7野的IMRT计划无显著差异。由此表明,IMRT计划能有效提高中央型非小细胞肺癌(NSCLC)的靶区剂量,又能使正常组织得到更好地保护。对应用于中央型非小细胞肺癌的IMRT,采用5野照射已完全满足临床剂量学要求。

Dose distribution of IMRT and 3D-CRT on treating central non-small-cell lung cancer

3D-CRT and IMRT were used in the radiation therapy of Central Non-small-cell lung cancer （NSCLC）,and the dose difference of the methods was estimated. Thirty-two patients suffering with II class NSCLC were selected. Based on CT images,each patient was given 1 3D-CRT （3 dimensional conformal radiotherapy） and 2 IMRT（intensity modulated radiation therapy） treatment plans （5 fields and 7 fields）,respectively,and the dose distribution was evaluated too. The results showed that PTVDmean and the PTVmax,PTVDmax （%） and CI of IMRT were both higher than those of 3D-CRT,but the uniformity was not as good as 3D-CRT. All indexes of lung and spinal cord treated with IMRT were lower than that treated with 3D-CRT. Moreover,there was no significance of the difference between 5 fields and 7 fields. In a conclusion,IMRT could not only decrease the target dose of NSCLC,but it can protect normal tissue from radiation damage effectively. And when IMRT was used,5 fields might be enough.