A radioactive tracer used in many diagnostic nuclear-medicine scans
Technetium-99m
A radioactive tracer used for diagnostic scans, helping doctors see how organs such as the bones, heart or kidneys are working.
What is Technetium-99m?
Technetium-99m is not a treatment but a radioactive tracer used to help take diagnostic scans in nuclear medicine. A small amount is usually injected, and it travels to the part of the body being studied so that area 'lights up' on a special gamma-camera scan, helping doctors see how organs such as the bones, heart or kidneys are working. It gives only a very low dose of radiation, and any radiation precautions afterwards are brief and simple. The main risks are a small chance of an allergic reaction and the low radiation exposure; it is given by a trained nuclear-medicine team.
Education and reference only. This is a plain-language guide to Technetium-99m — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Technetium-99m is a radiopharmaceutical, which means a medicine that is mildly radioactive and is used for scans rather than for treatment. It is the most commonly used tracer in nuclear-medicine departments. A small amount is given, usually as an injection, and it travels to a particular organ or tissue depending on how it has been prepared, so that part of the body can be seen on a special camera. It is used to take diagnostic images of many organs, such as the bones, heart, kidneys, thyroid and lungs, to help doctors understand how those organs are working. It is not a treatment and does not make you feel different.
How it works
Technetium-99m gives off a small amount of radiation that can be detected by a special device called a gamma camera. After it is injected, it travels to the part of the body being studied, where it gathers in a way that depends on how the organ is working. The gamma camera then picks up the radiation and turns it into pictures, so the area effectively 'lights up' on the scan. This lets doctors see not just the shape of an organ but how it is functioning, for example how blood flows to the heart or how the kidneys are draining. The radioactivity is short-lived and fades quickly, which is one reason this tracer is so widely used.
Company & origin
Originated / developed by: Specialist manufacturers.
A widely used radioactive tracer given in UK nuclear-medicine departments to help take diagnostic scans of organs such as the bones, heart and kidneys.
Practical use
How to take Technetium-99m
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- It is given by a trained nuclear-medicine team, usually as an injection, before the scan.
- You may need to wait a while after the injection so the tracer reaches the area being studied before the pictures are taken.
- Follow the simple radiation precautions you are given, such as drinking plenty of fluids to help flush it out.
- Tell the team if you are or might be pregnant or are breastfeeding, as this affects how the scan is planned.
- Tell the team about any past reactions to tracers or injected substances before the scan.
Weighing it up
Advantages & disadvantages of Technetium-99m
Advantages
- Lets doctors see how organs such as the bones, heart or kidneys are working, not just their shape.
- Uses only a very low, carefully controlled dose of radiation that fades quickly.
- A widely used, well-established tracer suitable for many different diagnostic scans.
Disadvantages
- It is a diagnostic tool only and does not treat any condition.
- Involves a small amount of radiation, so brief precautions may be advised afterwards.
- Rarely, an allergic reaction to the tracer can occur.
Practical use
Good to know
The most important thing to understand is that technetium-99m is a diagnostic tool, not a treatment: it is used to take pictures, not to cure or treat anything, and it will not make you feel ill or different. The radiation dose is very low and is carefully controlled, and the radioactivity fades quickly. Because of this, only brief and simple radiation precautions are usually needed afterwards, such as drinking plenty of fluids to help flush the tracer out and, sometimes, keeping a little distance from young children or pregnant people for a short time; the team will give clear instructions. A serious reaction is rare, but as with any injected substance an allergic reaction can occasionally happen, so you may be watched for a short while. Tell the team if you are or might be pregnant or are breastfeeding, as this affects how the scan is planned.
Who should not take it / use with caution
- It is used with care, and only when needed, in people who are or might be pregnant.
- People who have had a serious allergic reaction to a tracer should tell the team before any further scan.
- Breastfeeding may need to be paused briefly after some tracers, on the team's advice.
Monitoring
- Being briefly observed after the injection in case of a rare allergic reaction.
- Following simple radiation precautions, such as drinking fluids to help clear the tracer.
- Checking pregnancy or breastfeeding status before the scan is planned.
Side effects
- Usually none; most people feel nothing different from the tracer itself.
- Occasionally, brief discomfort or a small bruise where the injection is given.
- Rarely, an allergic reaction to the tracer, which the team is prepared to treat.
Key interactions
- Some medicines can affect how a tracer behaves in the body, so tell the team about all your medicines.
- The team will plan around other recent scans or tests as needed.
- Tell the team if you are or might be pregnant or are breastfeeding before the scan.
Available as: A solution given by injection (and, for some scans, prepared in other ways) as a diagnostic tracer.
Answers
Technetium-99m: frequently asked questions
What is technetium-99m used for?
It is a radioactive tracer used to take diagnostic scans, helping doctors see how organs such as the bones, heart or kidneys are working; it is not a treatment.
How does it work?
A small amount is injected and travels to the part of the body being studied, giving off a little radiation so that area 'lights up' on a special gamma-camera scan.
Is the radiation dangerous?
The radiation dose is very low and carefully controlled, and it fades quickly, so only brief and simple precautions, such as drinking plenty of fluids, are usually needed.
Will it make me feel unwell?
Most people feel nothing different; rarely an allergic reaction can occur, which is why you may be watched briefly after the injection.
Should I tell the team if I am pregnant?
Yes. Tell the team if you are or might be pregnant or are breastfeeding, as this affects how and whether the scan is done.
Authoritative sources
- BNF
- NICE CKS
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