What should you know about a PET scan with radioactive dye?

The tracer is often FDG, a substance related to glucose. Cells that use more glucose may collect more tracer and appear brighter. Increased activity can occur with cancer, infection, inflammation, or normal body processes, so a bright area is not a diagnosis by itself. The CT part shows anatomy, while PET adds information about tissue activity.

Clinicians may use the combined images to look for a primary tumour, assess lymph nodes, examine spread, or compare findings before and after treatment. The scan is interpreted with your symptoms, examination, laboratory results, and other imaging.

The imaging centre will tell you when to stop eating and whether plain water is allowed. Mention diabetes, pregnancy or possible pregnancy, breastfeeding, medicines, and difficulty lying still. You receive the tracer through an injection, then rest quietly while it travels through the body. During imaging, remain still and follow breathing instructions if given. The appointment includes preparation, uptake time, scanning, and recovery instructions.

Afterward, drink fluids if the team advises this and follow their guidance about close contact with young children or pregnant people. Keep the appointment letter and scan report for your treating team.

Tell staff immediately about swelling, wheezing, dizziness, rash, or trouble breathing after the injection. Seek urgent medical help for severe breathing difficulty, fainting, or rapidly worsening swelling. Contact the imaging centre if you develop a new concern after leaving or are unsure about radiation-safety instructions.

Ask what the scan is intended to answer, whether you need to change food or medicines, when the report will be available, and how the result may affect the next step. Ask whether you also need a biopsy or another scan before a diagnosis is made.