4DCT MIP图像与FDG PET-CT不同SUV阈值勾画NSCLC IGTV的比较研究

Abstract

Objective To compare the positional and volumetric differences between internal gross target volumes (IGTV) based on the maximum intensity projection (MIP) images of four-dimensional computed tomography (4DCT) and different standardized uptake value (SUV) thresholds of fluorodeoxyglucose (FDG) positron emission tomography/CT (PET/CT) for the primary tumor of non-small cell lung cancer (NSCLC).Methods Ten patients with NSCLC sequentially underwent contrast-enhanced 3DCT and 4DCT,as well as FDG PET-CT (with the same body position and positional parameters).IGTVMIP of the primary tumor was delineated on the MIP images of 4DCT.IGTVPET2.0,IGTVPET25,IGTVPET3.0,IGTVPET3.5,IGTVPET20％,IGTVPET25％,IGTVPET30％,IGTVPET35％,IGTVPET40％ and IGTVPETman were automatically and manually delineated based on different SUV thresholds of FDG PET/CT and different percentages of SUVmax.The differences in position,volume,matching index (MI),and degree of inclusion (DI) between IGTVPET and IGTVMIP were evaluated by paired t-test.Results There were significant differences in center coordinate between IGTVPET and IGTVMIP only in z axes (P =0.014-0.044).In terms of volume,IGTVPET2.0 and IGTVPET20％ were most similar to IGTNMIP,with volume ratios of 1.02 and 1.06(P =0.806).The highest MI was seen between IGTVMIP and IGTVPET2.0 and between IGTVMIP and IGTVPET20％ (0.46 and 0.45,P =0.603).The DI of IGTVPET20％ or IGTVPET2.0 in IGTVMIP was the highest (0.61 or 0.61,P =0.963).Conclusions IGTVPET20 and IGTVPET20％ are most similar to IGTVMIP in terms of volume and matching index,but neither of them could replace IGTVMIP in spatial position.When the IGTV of the primary tumor of NSCLC is delineated based on PET-CT,target position correction should be done with reference to 4DCT images while selecting the suitable SUV threshold. Key words: Tomography, positron-emission, fluorodeoxyglucose ; Tomography, X-ray computed,four-dimensional; Maximum intensity projection; Internal gross target volume; Lung neoplasms/radiotherapy