Nuclear Medicine

What is Nuclear Medicine?

Nuclear medicine tests use drugs with small amounts of radiation in them called radiopharmaceuticals. These are also known as radionuclides or radioisotopes.

For most Nuclear Medicine tests, patients have the radioactive substance injected into them. But for some tests, patients are given something to eat or drink or gas to breathe in with the radioactive substance in.

None of these things are more painful than if the material was not radioactive. For example, an injection will feel like a sharp scratch.

Most people will then be placed under a large camera called a gamma camera to image the radioactive substance in your body. This camera does not completely enclose the patient and you will be able to see around it. The camera will move close to you but will not touch you. If it does touch you for any reason, some detectors will cause it to move away from you.

Some Nuclear Medicine tests involve taking a blood sample instead of using the gamma camera. The blood samples are then tested.

Nuclear Medicine tests often give us different information to Radiology. Nuclear Medicine focuses on how organs are working.

What do I need to know?

The video below discusses what is involved in a Nuclear Medicine procedure.

Take away points

  • For Nuclear Medicine the source of radiation is inside you.

  • You should let the person doing your test know if you are pregnant or think you could be pregnant, or if you are breastfeeding.

  • When you leave the department, you will be given some instructions which you will need to follow for a period of time to minimise the dose to others around you.

  • We are all exposed to radiation throughout our lives and even eat small amounts of radiation for example in bananas.

  • The risk to you will be less than the benefit of the information your doctor will get from the test.

Molecular Radiotherapy (using Nuclear Medicine to treat disease)

As well as being used for finding a problem (diagnosis), radiopharmaceuticals can be used for treating disease. In this case, larger amounts of the radioactive substance are given to the patient, and this mainly goes to a point in the body depending on the radiopharmaceutical used. Usually, different substances are used in treatment to those used in diagnosis.

In therapy, the aim is to kill diseased tissue. For some treatments, you will be asked to stay in the hospital but for some, you will be allowed to go home.


  • Nuclear Medicine will only be used if a healthcare professional can show that the benefit to you is greater than the risk (justified).

  • The equipment will be maintained to reduce the dose to keep the dose and risk to you as low as possible.

  • The individual carrying out the imaging will be trained to keep the dose and risk to you as low as possible.

  • If you have any more questions, please ask a healthcare professional.

If you'd like to find out more about the risks of using Nuclear Medicine, there is more information within the 'Radiation Risk' section.