Abstract ObjectiveTo compare the difference of pulmonary dosimetry and the incidence of radiation-induced lung injury in patients with invasive thymoma after three-dimensional conformal radiotherapy(3D-CRT)and intensity-modulated radiotherapy (IMRT)operation.MethodsFrom January 2014 to June 2016,28 patients with invasive thymoma treated in Huizhou Central People′s Hospital in Guangdong Province were selected and they were randomly divided into 3D-CRT group(n=14)and IMRT group(n=14).After surgery,radiotherapy was necessary.They were provided with 3DCRT and IMRT separately in the two groups.Plan of 3D-CRT and IMRT were designed for every patient and pulmonary dosimetry in two-radiotherapy plans was compared.They were all followed up,and the incidence of radiation-induced lung injury was also compared between the two groups.ResultsThe lung V5was(65.68±11.32)%in IMRT group,which was higher than that in 3D-CRT group[(57.17±9.46)%](P< 0.05).The lung V10,V20,and V30in IMRT group was(45.78±10.00)%,(23.19±7.12)%,and(13.40±5.15)%respectively,which was lower than that in 3D-CRT group[(47.70±9.48)%,(26.54±7.76)%,and(15.10±4.90)%accordingly](P<0.05).During the follow-up,there were two cases occurred with radiation-induced lung injury in IMRT group,one in the 3D-CRT group,which was not displayed significant difference about the incidence of radiation-induced lung injury(P>0.05).ConclusionPostoperative IMRT for invasive thymoma,the radioactive volume in low-dose area of the lung is larger than 3D-CRT,but in 10 Gy,20 Gy,and 30 Gy the radioactive lung area is smaller in comparison with that by 3D-CRT,which indicates the protection of lung is better when the dosage is higher.
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