Melanoma: PET scan
If you have a high stage melanoma you may need to have a PET (positron emission tomography) scan, which uses low-dose radioactive sugar to measure the activity of cells in the body. A very small amount of a mildly radioactive sugar is injected into a vein in your hand or arm before you have the scan. Areas of cancer are normally more active than surrounding tissue and absorb more of the sugar, which shows up on the scan. This helps the doctor decide if surgery is the best option. It can also help when the doctor thinks the cancer has spread but doesn’t know where and is most useful in people with advanced stages of melanoma.