What should you know about a rubidium PET scan?

PET imaging detects signals from a small amount of radioactive tracer as it moves through the body. Rubidium behaves like potassium and is used to assess tissue perfusion, particularly blood flow through the heart muscle. A PET-CT scanner combines this functional information with CT anatomy. For many cancer assessments, clinicians choose a tracer such as FDG because active cells may take it up differently from surrounding tissue. The correct tracer depends on the clinical question, so the name of a scan should be checked with the ordering team.

Confirm the tracer, scan area, fasting instructions, medication changes, and whether caffeine or strenuous activity should be avoided. Tell the imaging team about pregnancy, breastfeeding, diabetes, kidney problems, allergies, and any difficulty lying flat. Wear comfortable clothing and follow the department's instructions about food and drink. After the scan, ask when results will be available and whether any short-term radiation precautions apply to your specific tracer.

A scan appointment does not replace urgent medical assessment. Seek immediate help for chest pain, severe breathlessness, fainting, new weakness, or a sudden change in consciousness. Contact the imaging department for a new rash, swelling, or feeling unwell after the appointment, and tell your cancer team if symptoms worsen while you are awaiting imaging.

Ask why rubidium was selected, what tissue the scan is evaluating, and whether the examination is for heart blood flow or cancer assessment. Clarify whether CT contrast is involved, how to prepare around medicines and meals, and what other imaging may be needed. Ask who will explain the report and how it will affect the next decision.