PET scan is a technique that uses short-lived radioactive drugs to produce three-dimensional coloured images of tissues within the body, much like CT scan and MRI. While CT scan and MRI look at anatomical structures, PET scan measures the function of tissues. PET scans can determine whether a tissue is actively growing and can aid in determining the type of cells within a particular tumour.

During a PET scan, the patient is first injected with a glucose (sugar) solution containing small amount of radioactive material. The glucose (along with the radioactive material) is picked up by the active cells and the same is shown a bright spot on scanning. By combining PET Scan with CT scan, an accurate anatomical localisation of the abnormal spot can be done.

PET Scan picks up those areas where the glucose (along with radio tracer) is accumulated. This happens typically in Cancer cells (as they divide rapidly), infections as well as after injury. Thus, a bright spot in pet scan is not always synonymous with cancer. Your doctor uses the information from PET scan in the light of clinical background and other tests like biopsy etc to reach a final diagnosis.

PET scan is used for diagnosing as well as staging of Lung cancer. The cancer in the lung shows up as a bright spot and in case the lung cancer has spread to glands in the chest or to other areas of the body, these also show up as bright spots. Thus, PET scan has immense role to play in patients of lung cancer.

As PET scan also uses X-Ray Technology as well as radioactive material, pregnant women must not undergo PET scan.