Hello

Positron emission tomography (PET) scan is an functional imaging test of brain.It shows how the brain and its tissues are working.
It uses a radioactive substance known as tracer to detect brain disease or injury.
It is almost a painless procedure.Only mild pain is felt during insertion of needle for radioactive substance administration. Radiotracer substance is injected in the vein.
Your friend should go for this test as it is indicated in his case.

Get well soon.
Take Care
Dr.Indu Bhushan

A PET SCAN or positron emission tomography is one type of imaging test. It shows how organs and tissues are working. A brain PET scan is an imaging of the brain using this technique. A small amount of substance known as tracer is given through a vein usually which will reach brain and help describing the functioning and tissue of the brain. You will lie down on a table which will slide into a tunnel shaped scanner. The result will be seen by your doctor on a monitor as 3D images. A PET scan causes no pain so dont worry. A sharp stinge may be felt when needle is inserted to inject the tracer. Its very mild. An intercom in the room will help you communicate with others outside. Do not panic. Stay relaxed and still so that the machine can produce clear images. Also please inform the doctor if you are claustrophobic or pregnant or allergic or on some medications. Don't worry.