[Lani]

PET scans light up in areas where there is increased glucose uptake--that can be infection or inflammation or cancer. Radiation induced damage to normal cells as well as cancerous cells causes inflammation.

Perhaps your doctor will order a dedicated CT (resolution much better than the CT they do in conjunction with the PET from what I understand) to better determine the size of the lesion. Small lesions in the lung are common and are rarely cancer from what I have read and been told.

Hope some of this helped!