[Detection of mediastinal lymph node metastasis from lung cancer with positron emission tomography (PET) using 11C-methionine].

Twenty-five patients with primary non-small cell lung cancer underwent the positron emission tomography (PET) using 11C-methionine to detect the mediastinal lymph node metastasis. We introduced the positron angiography to recognize precisely the anatomical orientation of the mediastinal lymph nodes. The 11C-uptake of the lymph node was expressed with distribution absorption ratio (DAR). A total 107 lymph nodes were examined. The average DAR in metastatic lymph nodes (n = 28) was 3.89 while that of non-metastatic nodes (n = 79) was 2.38 indicating a significant difference (p < 0.001). The most adequate threshold for detection of metastasis was 3.3 with sensitivity of 100%, and specificity of 87.3% and overall accuracy of 89.7%. Metastasis of squamous cell carcinoma was diagnosed more accurately than that of adenocarcinoma. Thus, PET using 11C-methionine may offer a new method to detect the mediastinal lymph node metastasis from lung cancer.