Abstract:

Objective To evaluate the influence to stage and the treatment planning in non-small cell lung cancer(NSCLC)by CT、PET/CT.To define the correlation of gross tumor volume(GTV)by PET/CT and pathology.Methods From March 2006 to July 2008,37 NSCLC patients were studied,21 cases received surgical resection and 16 cases received radiotherapy based on PET/CT.All patients had PET/CT scans of all body before surgery or radiotherapy and routine pathology examination after surgery.The tumor size at X(lateral direction)、Y(ventrodorsal direction)and Z(craniocaudal direction)axes were measured on CT、PET/CT and pathology examination,respectively.TNM stage change the treatment planning in a significant number of patients,both the CT and PET/CT images were transferred to the RT planning workstation for contouring.GTV,pathologic nodal and primary tumor volumes were first defined in the conventional manner based on CT and PET/CT images.Results TNM stage was changed in 19 cases(51.4%)and the treatment planning was changed in 12 cases(37.8%)after PET/CT.There was no significant difference in the tumor size at X 、Y axes(P＞0.05);and there was significant difference in the tumor size at Z axes.Of the 16 patients in radiotherapy group,the primary tumor GTV was increased in 4 cases by detecting additional nodal disease burden,and decreased GTV in 7 cases by differentiating atelectasis and postobstructive pneumonia from tumor.Conclusion PET/CT alter TNM stage and the treatment planning in NSCLC in a significant number of patients,there was almost total agreement on the gross tumor volume by PET/CT and pathology.GTV could be used for radiation therapy by PET/CT instead of the GTV by pathology.PET/CT is superior CT on delineation of the gross tumor volume for radiation planning.

Key words: Lung neoplasms, Non-small cell lung cancer, Pathology, 18FFDG- PET/CT, Gross tumor volume