[Radiological evaluation of the tumour response after lung stereotactic radiotherapy].

Stereotactic body radiotherapy is the treatment of choice for medically non-operable T1-T2 N0M0 non-small cell lung cancer or for slowly growing lung metastases with no evolutive primary tumour. Lung stereotactic radiotherapy provides an excellent local control rate, higher than 80%. Nevertheless, although the clinical toxicity rate is less than 5%, postradiation radiological reactions surrounding the tumour, called "radiological radiation pneumonitis", are very frequent, which makes it difficult to evaluate the tumour response. Firstly, this review describes the lesions of acute and chronic radiation pneumonitis and the CT images suggesting a local recurrence. Then, we evaluated the place of PET after stereotactic body radiotherapy in the follow-up period. Finally, we suggest an algorithm helping physicians in the follow-up of such treated patients.