Is a PET scan painful?

A healthcare professional injects a small amount of FDG radiotracer into a vein. The needle may sting briefly, and the area can feel tender afterward. You then rest quietly while the tracer moves through your body. During imaging, you lie on a narrow table that passes through the PET-CT scanner. The machine does not touch or cut you, but holding one position can become uncomfortable, especially if you have back or joint pain. The scanner is open at both ends, though some people feel uneasy in enclosed spaces. Tell the team before the appointment if you have difficulty lying flat, claustrophobia, or trouble remaining still. A PET scan shows areas of increased tracer activity; activity can occur for reasons other than cancer, so the images need clinical interpretation.

Follow the preparation instructions about eating, drinking, medicines, and blood glucose. Wear comfortable clothing and remove metal items when asked. Keep warm and relaxed during the waiting period, because movement can affect the images. Tell the team about diabetes, pregnancy, breastfeeding, allergies, recent illness, or difficulty with intravenous access. During the scan, use slow breathing and mention pain rather than forcing yourself to stay in a position you cannot tolerate. More information about the procedure is available in the PET-CT Scan guide and the FDG Radiotracer explanation.

Contact the imaging service promptly if increasing redness, swelling, warmth, drainage, or severe pain develops around the injection site. Seek urgent medical help for trouble breathing, facial swelling, fainting, or widespread hives after the appointment. These symptoms need assessment even though serious reactions are uncommon. If pain comes from an existing condition and makes lying still difficult, tell the team before the scan so positioning or support can be discussed.

Ask whether your scan uses FDG, how long you may need to lie still, and what preparation applies to your medicines or diabetes. You can also ask how discomfort will be managed if you have limited mobility.