Diagnostic radiopharmaceuticals
Also known as: radiotracers, nuclear medicine tracers, PET tracers
Radioactive medicines given in tiny amounts so that a gamma camera or PET scanner can show where they accumulate: bone turnover, blood flow to the heart, thyroid activity, glucose use by tumours.
- Biological target
- Physiological processes (bone turnover, perfusion, glucose metabolism, receptor binding) imaged through the tracer's distribution
- Also called
- radiotracers, nuclear medicine tracers, PET tracers
Mechanism of action
A radioactive isotope is attached to a molecule the body handles in a known way: a phosphate analogue that binds forming bone, a glucose analogue trapped in metabolically active cells, iodine taken up by the thyroid, or a compound retained by well-perfused heart muscle. The radiation the isotope emits is detected from outside and mapped, so the image shows function rather than anatomy; combining it with CT adds the anatomy. The radiation dose is kept low by using short-lived isotopes and small amounts.
Members of the class
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Conditions treated
Class effects
- A small radiation dose; reactions to the tracer itself are rare
Cautions
- Pregnancy and breastfeeding declared before the injection
- Radiation-safety advice for the hours after the scan (fluids, bladder emptying, distance from pregnant women and young children)
- Preparation specific to the tracer: fasting for FDG, medicine timing for perfusion studies
Class interactions
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