| Objective:To compare the cone-beam CT(CBCT) deformable image registrationof PTV enlarging distance and intensity-modulated planning(CT-IMRT) for patients withlung cancer, metrology comparative study and evaluate their characters.Methods:Fifteenpatients with no small cells lung cancer were in the study.Two sets image,before and afterradiotherapy,were acquired every week.Then delineated the targeted volume and made theplanning (CT-IGRT) according the enlarging distance data, made the comparison withformer planning (CT-IMRT) for fractionation dose, accumulation dose and dose-volumehistogram of both lung,spinal-cord,PTV.The difference of two plans was analyzed by Tsign rank test.To compare with the NTCP difference between the two plans, which wasanalyzed by wilcoxson test.Results:The max,min and mean dose of PTV,the total lungV5,V10,V20,V30,V40,V50were similar in both plans.CBCT based image registration theMPTVsignificantly lower than the corrected one.CBCT based image registration the lungsDmeanis lower than the IMRT,difference have statistical significance.The NTCP had thedecend tendency followed by the increasing of lung volume, V5/V10/V20/V30/V40/V50（all P<0.05）.Conclusion:CBCT based image registration can reduce PTV, the meandose of total lung, NTCP,and increase PTV dose.This provides a tool for exploringaccurate radiotherapy strategies. |
