A PET Scan or a Positron Emission Tomography is a test that would give your doctor the freedom to study your organs and tissues in detail. They are mostly ordered by the doctor when there arises the need for detecting cancer, heart problems, brain disorders and problems with the Central Nervous System. 

Combined with CT or MRI scan, a PET scan gives a clue about how diseases are unfolding in your body, and how the blood is flowing through the veins, the oxygen levels and generally, how your body is working at the cellular level. 

In this kind of scan, the doctor first injects you with a radiotracer, consisting of radioactive material and tagged to natural chemicals (for example, glucose). A doctor studying the results of the scan would be able to see problem areas or areas where the radiotracer builds up. These are called hotspots or cold spots. Normal cells do not have too much glucose in them, but cancer cells are quite high in glucose. The radiotracer with glucose will light up in the problem areas. 

For example, if your doctor suspects cancer then the cancer cells would show up as bright spots on the PET scans. This would be helpful in checking whether cancer has spread, if the treatment is working or if there is a recurrence. 

Hence, PET scans let the doctor show how your cells are working, and what changes have been happening. Here’s how you prepare for a procedure for PET scan:

• Change into the hospital garb
• The doctor would either inject the tracer or ask you swallow it or breathe it in
• A waiting period of over 30 minutes to absorb the tracer in the body
• Now you have to lie on the table attached the scan machine and be very still until the procedure is completed.