V20、MLD与放射性肺损伤的相关性研究

目的研究V20、MLD与放射性肺损伤发生的相关性，指导临床放疗计划的制定，避免或减少放射性肺损伤，提高局部控制率，改善患者生存质量。方法自2008年8月至2010年6月，47例符合研究条件的肺癌患者人组。所有患者均接受三维适形放疗，应用6MVX-线照射，剂量50—70Gy／25—35f。制定放疗计划，生成剂量-体积直方图（DVH），得到物理参数V20及MLD，分析以上参数及其他临床因素对放射性肺损伤的影响，放疗计划要求V20≤30％，脊髓总量≤45Gy。放疗结束后定期行胸片及CT复查，根据辅助检查结果及临床表现诊断放射性肺损伤的发生，依据RTOG分级标准评价放射性肺损伤的程度。结果47例中有15例发生放射性肺损伤，放射性肺损伤发生率为31．9％（15／47）。当V20≤25％和〉25％时，放射性肺损伤发生率分别为14．3％和46．2％，差异有统计学意义（P〈0．05）。当MLD≤15Gy和〉15Gy时，放射性肺损伤发生率分别为14．3％和57．9％，差异有统计学意义（P〈0．05）。结论V20、MLD与放射性肺损伤有相关性，对预测放射性肺损伤有一定价值。

Relation of V20 and MLD to radiation-induced lung injury

Objective To investigate the relation of V20 and MLD to radiation-induced lung injury. Methods From Aug 2008 to Jun 2010,47 patients with lung cancer and met the study criteria were enrolled. All patients receive 3D conformal radiothera- py by 6MVX-ray, and the doses ranged between 50Gy to 70Gy. DVH was gained through 3-dimensional TPS. The radiation treat- ment planning was V20 ≤ 30% and the spinal cord volume was≤45Gy. Radiation-induced lung injury was diagnosed based on contrasted CT combined with clinical symptoms, and the extent of injury was evaluated according to RTOG grading crite- ria. Results The total incidence of radiation-induced lung injury was 31.9% （15/47）. While the incidence of lung injury was higher in the group of V20 〉 25% （46. 2% ） than that in the group of V20 ≤〈25% （ 14. 3%, P 〈 0. 05 ）. The incidence of lung injury was lower in the group of MLD≤ 15Gy （ 14. 3% ） than that in the group of MLD 〉 15Gy （57.9% ,P 〈0. 05）. Conclusion The radiation-induced lung injury related significantly to V20 and MLD that could help to predict the injury.