Abstract
Two patients with lung cancer, which was difficult to diagnose by chest X-ray film and CT scan, were examined by positron emission tomography using 11C-methionine. We introduced a respiration-gated scanning and positron angiography to improve the spatial resolution and anatomical orientation. Case 1 was diagnosed by bronchofiberscopy as having double cancer at the same site as pulmonary suppuration in the left lower lobe, and it was difficult to decide the margin between cancer and inflammatory infiltration by chest X-ray film and CT scan. Case 2 was diagnosed as having recurrent adenocarcinoma in the right lower lobe. The anatomical structure of the hilus and mediastinum was obscure because of the previous operation, and the diagnosis of metastatic lymph adenopathy was difficult. In both cases, cancer and metastatic lymph adenopathy were clearly visualized, and the border of the cancer was easily demonstrat-ed by the respiration-gated scanning and positron angiography.
Positron emission tomography using 11C-methionine is a new diagnostic method for lung cancer based on amino acid metabolism and seems to be useful in the diagnosis of lung cancers which are difficultly to diagnose by X-ray film and CT scan.
