肺灌注显像联合剂量体积直方图参数预测放射性肺炎的临床研究

 目的　观察接受三维适形或调强放疗的肺癌患者放疗前后肺灌注显像的变化、肺受照射的剂量体积直方图（DVH）参数等，并结合临床因素，探讨其与放射性肺炎发生的相关性。方法　18例接受三维适形或调强放疗的肺癌患者放疗前后行肺灌注显像检查，比较照射前后肺灌注显像的变化。放射性肺炎的评价按美国肿瘤放疗协作组（RTOG）急性放射性肺炎标准评定。获得的CT与单光子发射CT（SPECT）肺灌注图像融合后，将等剂量曲线投影到SPECT图像，将传统的DVH转换成f-DVH。将f-DVH曲线中每例患者的V5、V10和V20所对应的灵敏度与特异度相加，取其最大值，寻找到曲线的界值。分析放疗前后肺灌注显像变化及肺受照射的DVH与放射性肺炎发生的相关性。结果　18例患者中，33.3 %（6／18）发生了2级以上放射性肺炎。放疗前后肺灌注受损加重者2级以上放射性肺炎发生率为62.5 %（5／8），肺灌注受损改善者发生率为10.0 %（1／10）。f-DVH图曲线中V5、V10和V20的界值分别为53 %、41 %和27 %，以V5对中重度急性放射性肺炎的预测准确度最高。放疗前后肺灌注显像的变化联合全肺DVH参数V5是放射性肺炎最强的预测因素。结论　肺癌患者放疗前后肺灌注显像能反映患侧肺灌注功能的变化。放疗前后肺灌注显像的变化联合DVH参数V5有望作为预测放射性肺炎发生的指标。

Clinical research on combination of dose-volume histogram parameters with pulmonary perfusion imaging to predict the radiation pneumonitis

Objective　To evaluate the lung exposure dose-volume (DVH) parameters and other indicators of lung perfusion imaging before and after three-dimensional conformal or intensity modulated radiation therapy for lung cancer patients, and combined with clinical factors, to explore relationship with radiation pneumonitis occurred. Methods　18 patients were selected for data analysis. Lung perfusion scintigraphy was detected before and after three-dimensional conformal or intensity modulated radiation therapy for lung cancer. Lung perfusion changes were compared before and after irradiation. Evaluation of radiation pneumonitis was assessed by the Radiation Therapy Oncology Group (RTOG) acute radiation pneumonitis standard. After the CT and SPECT lung perfusion images were transferred to Varian, the Eclipse 3D treatment planning system, image fusion after dose curve projected onto the SPECT images, and the DVH was converted into a f-DVH diagram. Analysis of pulmonary perfusion imaging changes before and after radiotherapy combined with lung irradiation dose volume parameters and radiation pneumonitis. Results　In the whole group, 33.3 % (6/18) cases occurred more than 2 radiation pneumonitis. Before and after radiotherapy, the damage to the lung perfusion was more than 2 radiation pneumonitis incidence [62.5 % (5/8)], and impaired pulmonary perfusion improvement was 10.0 % (1/10). DVH parameters to V5 severe RP forecasted high accuracy. In curve for each patient, boundary values of V5, V10 and V20 were 53 %, 41 % and 27 %. Before and after radiotherapy it was found that lung perfusion changes and the whole lung V5 portfolio were the strongest predictors for radiation pneumonitis after radiotherapy. Conclusion　Pulmonary perfusion imaging in patients with lung cancer is able to reflect changes in the function of ipsilateral lung perfusion before and after radiotherapy. Changes in the ipsilateral lung perfusion detected before and after radiotherapy combined with V5 are expected to serve as indicators to predict radiation pneumonitis.