The presented results indicate that [11C]erlotinib scans could distinguish NSCLC tumors that express activating mutations in the EGFR TK domain and are sensitive to erlotinib treatment, from tumors that harbor wtEGFR or the double-mutated (L858R + T790M) receptor and do not respond to erlotinib therapy. This evidence concerns the gene EGFR and non-small cell lung carcinoma.