Comparison of before and after CBCT image registration based on the lung cancer intensity-modulated planning / 中华放射肿瘤学杂志

ABSTRACT

Objective To study the CBCT image registration of PTV enlarging distance and IMRT planning(CT-1) for patients with lung cancer,and evaluate their characters.Methods Ten patients with lung cancer were included in the study.Two sets image,before and after radiotherapy,were acquired every week.Then delineated the targeted volume and made the planning (CT-2) according the enlarging distance data.To comparize the parameters of DVH for lung and spinal cord,volumes and dose of PTV and NTCP with CT-1 and CT-2.The difference of two plan was analyzed by covariance analysis or Wilcoxson's z-test.Results The max,min and mean dose of PTV,the lung V5,V10,V20,V30,V50 were similar in both plans (P =0.242-0.663).There was superiority in CT-2 of PTV and lung's mean dose(P =0.049,0,035).The NTCP had the decent tendency followed by the increasing of lung Vs,V10,V20(P =0.146,0.053,0.000).Conclusions CBCT based image registration can reduce PTV,the mean dose of lung,NTCP,and increase PTV dose.This provides a tool for exploring acurate radiotherapy strategies.