Eligibility Criteria:
Inclusion Criteria:
* Male or female patients,
* Age over 18 years and below 75-year-old,
* Good general condition: WHO performance status ≤ 1,
* Histological evidence of non-small cell lung cancer,
* Measureable tumour according to RECIST 1.1 evaluation criteria,
* Mediastinoscopy or endobronchial ultrasound to prove the histological stage N2/N3,
* Patient eligible to curative-intent radio-chemotherapy,
* Absence of pleural involvement, of pulmonary or extra-thoracic metastatic localisation,
* Absence of co-morbidity contra-indicating radio-chemotherapy,
* Lung function: FEV1 ≥ 40% of theoretical value and DLCO/VA ≥ 60% of theoretical value and PaO2 ≥ 60 mm Hg,
* Tumour FDG uptake higher than mediastinal background noise on baseline PET/CT,
* Haematological parameters:
* Neutrophil count ≥ 1.5x109/L and platelet count ≥ 100x109/L,
* Haemoglobin ≥ 9 g/dL,
* Provisional RT plan confirming that the dose objectives (minimal dose of 62.7 Gy (95% of the prescribed dose) in 98% of target volumes and 70.3 Gy for the "boosted" volume at 74 Gy) and constraints (lungs, spinal cord) are met (ICRU83),
* Estimated creatinine clearance ≥ 60 mL/min,
* Signed informed consent
* Affiliated or beneficiary of a social benefit system
Exclusion Criteria:
* Histology other than non-small cell lung cancer,
* Absence of FDG uptake on FDG-PET/CT scan before induction chemotherapy,
* Patients for whom curative radiotherapy is not indicated (tumour extension, metastases, general condition, co-morbidities),
* Significant interstitial disease on CT scan,
* Previous neoplastic disease of less than 5 years duration or progressive (without basal cell carcinoma of the skin, in situ carcinoma of the cervix),
* Previous thoracic radiotherapy,
* Patient enrolled in another therapeutic trial,
* Pregnant women or women of child-bearing potential or breast feeding mothers,
* Adult subjects who are under protective custody or guardianship,
* Patient unable to comply with the specific obligations of the study (geographic, social or physical reasons),
* Uncontrolled diabetes with blood glucose ≥10 mmol/L,
* Hypersensitivity to the active substance (FDG) or to any of the excipients,
* Patients unable to understand the purpose of the study (language, etc.).