Pet scan results were fine so why do they want me to have a bronchial scope done ?wouldn't the scan have shown any spread to the lymph nodes already ?

Variable conditions: Pet scan is quite sensitive in detecting metabolically active tumors. Sometimes other issues contribute to the patient's health such as infectious components or problems in lung ventilation.You should question your physician about any test or change in your health care. You should have an answer to any question concerning your health.

Ask for explanation: This depends on what is shown in the lung on the ct and your symptoms. Pet is good but not an answer for everything. You should be able to ask your doctor for an explanation.

Not necessarily : Pet scans can prevent lymph node biopsies when they are positive, but when staging disease a negative "scan" does not exclude metastasis ( particularly if lung cancer metastasis is the question).

Not if very small: Pet scans are quite accurate in lung cancer, as long as the cancer is metabolically active and bigger than 10 mm (or 3/8 of an inch). Pet can sometimes detect cancers smaller than 10 mm, but not reliably. So, the normal pet scan is very good news, but your physicians have some concern or are being very diligent and want to look everywhere they can for cancer.