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摘要Purpose: It is important to minimize lung dose during intensity-modulated radiation therapy (IMRT) of non-small cell lung cancer (NSCLC).In this study, IMRT plans with inhomogeneous dose distributions are created in order to reduce the dose to lungs, especially the low dose region.And further reduce the incidence of radiation pneumonia of IMRT and increase the expected tumor control probability for NSCLC patients.Materials and Methods: Ten NSCLC patients with lung tumor on the right side treated at our institution between July 2014 and October 2015 were selected.The total dose for planning target volume (PTV) was 60 Gy (2Gy/fraction).For each patient, two IMRT plans with six beams were created in Pinnacle treatment planning system.The dose homogeneity of target was controlled by constraints on the maximum and uniform doses of target volume.One IMRT plan (IMRThome) was made with homogeneous target dose (the resulting target dose was within 95%-107% of the prescribed dose), while another IMRT plan (IMRTinho) was made with inhomogeneous target dose (the resulting target dose was more than 95% of the prescribed dose).During plan optimization, the dose of cord and heart in two types of IMRT plans were kept nearly the same.The doses of lungs, PTV and organs at risk (OARs) between two types of IMRT plans were compared and analyzed quantitatively.Results: For all patients, the lung dose was decreased in the IMRT plans with inhomogeneous target dose.On average, V20 of lungs decreased from 27.9±3.8% (IMRThomo) to 23.7±2.7% (IMRTinho) (p < 0.001), and the mean lungdose decreased from 15.7±2.1% (IMRThomo) to 14.1±1.8% (IMRTinho) (p < 0.001).V5 of lungs decreased from 57.1±8.3% (IMRThomo) to 51.6±7.4% (IMRTinho).V10 of lungs decreased from 42.6±7.1% (IMRThomo) to 37.4±6.4% (IMRTinho), and V30 of lungs decreased from 19.6±2.4% (IMRTinho) to 17.5±2.0% (IMRTinho).The dose to normal tissue was also reduced.There were no significant differences between the two IMRT plans on V25, V30, V40, V50 and mean dose for heart.The maximum doses of cords in two type IMRT plans were nearly the same.Conclusions: IMRT plans with homogeneous target dose could result in high dose to lung, and consequently increase the incidence of radiation pneumonia.IMRT plans with inhomogeneous target dose could protect lungs better and may be considered as a choice for treating NSCLC.