[201Tl SPECT for suspected lung cancer in a case of a systemic arterial supply to the lung without sequestration].

201Tl SPECT showed negative result for the presence of a malignant lesion in a 54-year-old male suspected with primary lung cancer on plain x-ray CT. Thin-section contrast x-ray CT and aortography revealed anomalous left lower pulmonary artery arising from the aorta which mimicked a pulmonary mass lesion in the initial study. 201Tl SPECT gave us a clue to the correct diagnosis.