Impact of PET/CT on the treatment planning and target volume delineation of radiotherapy in the patients with non-small-cell lung cancer complicated by atelectasis

Objective To investigate the impact of PET/CT on the treatment planning and target volume delineation of radiotherapy in patients with NSCLC complicated by atelectasis.Methods Pre-treatment PET/CT scans were performed in 36 patients with pathologically proven NSCLC complicated by atelectasis of different severity undergoing curative 3D-CRT planning.Clinical staging before and after PET/CT was compared and the change of treatment plan was evaluated.The target volumes were delineated by CT and PET/CT.Results PET/CT results changed the clinical staging in 18 (50.0％,18/36) patients.PET/CT identified distant metastatic diseases in 11 (30.6％,11/36) patients,thus excluding their eligibility for curative 3D-CRT.Of these 11 patients,managements were changed to palliative radiotherapy in 3 patients,chemotherapy in 7 patients and best supportive therapy in 1 patient.In the 25 patients with curative 3D-CRT,PET/CT altered the radiotherapy volume in 21 cases,including 12 with volume reduction,7with volume enlargement and 2 with location change.Three patients were given additional conventional radiotherapy,since PET/CT indicated supraclavicular nodal metastases.In the 3 patients with palliative 3D-CRT,2 had target volume reduction and 1 had target volume enlargement after PET/CT.Conclusions PET/CT may play a role in the management of patients with NSCLC complicated by atelectasis.It is also helpful for accurate delineation of target volume in 3D-CRT treatment planning. Key words: Carcinoma, non-small-cell lung;  Atelectasis;  Tomography, emission-computed; Tomography, X-ray computed;  Radiotheraphy;  Deoxyglucose