Abstract:

Objective To observe the incidence of acute radiation pneumonitis(RP) after  intensity modulated radiation therapy,and to explore the  relationship between the incidence of RP and the parameters from  dose-volume histogram(DVH)in the patients with non-small cell lungcancer(NSCLC).Methods By Pinnacle 7.6c TPS，46 patients with NSCLC   were treated by IMRT.The values of  the percentages of the lung volumes receieved 5,10,20,and 30 Gy radition to the total lung volumes (V5 ,V10,V20,V30) and mean  lung dose(MLD)  were  observed，and its correlation with acute RP was analyzed.Results The incidence of acute RP of the patients with NSCLC was 37.0%(17／46），among then there were 29 cases (63.0%) of Grade 0 (non-pneumonitis group),12 cases  (26.1%) of Grade 1,5 cases(10.9%) of Grade 2, and there were no Grade 4 and  5 RP. The values of V5 ,V10 ,V20 ,V30,and MLD  of lung were 53.34 %,43.12%,24.15%,15.36 %,and 16.02 Gy.The values of V5 ,V10 ,V20 ,V30,and MLD   in  pneumonitis group were 57.81％,48.91％,31.34％,17.83％,21.71 Gy，and they were 49.81％,39.78％, 21.82％, 13.12％,and 13.71 Gy  in non-pneumonitis group,there were significant differences between two groups(P<0.05).Conclusion The intensity modulated radiation therapy in treatment of NSCLC can protect thelung tissue,and the parameters of DVH such as  V5 ,V10 ,V20 ,V30 and MLD can predict the occurrence of RP.

Key words: cancer, non-small cell lung；intensity modulated radiotherapy;dose-volume histogram;radiation pneumonitis