Sentinel Node Scan

What is a Sentinel Node Scan?

A sentinel node scan identifies the first lymphatic node or nodes of the lymphatic pathway from the primary tumour. This will help Surgeons to locate and remove only the required lymphatic nodes. The scan will be done either on the day of your surgery or the day before depending on your surgery time and agenda scheduling.


There is no special preparation for the examination, and you may eat and drink normally before this appointment. You can take any medication as usual.


If you are pregnant or breastfeeding it is essential that you let us know before your appointment date. If you are a female of child bearing age (12-55 years old), you will be asked about your pregnancy and breastfeeding status. If you are unable to confirm you are not pregnant a pregnancy test may be performed.


All patients are entitled to have a chaperone present for any consultation, examination or procedure where they feel one is required.

The examination

On your arrival you will be asked to remove clothing.Following this, a radiographer will explain the procedure to you and will ask you a few questions about your health records. You will then have a small amount of radioactive tracer injected near the tumour, using a very fine needle. The injected tracer will drain from the tumour site and into the lymphatic system. It emits gamma rays which can be detected by a piece of equipment called a gamma camera.

Straight away after the injection you will be asked to massage the area around the injection site for 5minutes to encourage the injection to drain into the lymph nodes in your armpit.

Following this, images will be acquired to map the drainage. The machine is very quiet and you do not go through a tube or tunnel. The radiographer will then mark where the nodes are, if visible, with a waterproof pen on your skin.

If there is no drainage visible, you will be then asked to return at a later time to repeat the same imaging process (second injection). This time gap is to allow the tracer to be fully absorbed into your lymphatic system for us to see it. Between the injection and the scan you may eat and drink normally. If after this time the lymph nodes for marking are still not visible, no more images will take place and your consultant would be informed about the lack of skin marking.

Who will be present?

Your scan will be performed by a Nuclear Medicine trained member of staff which stays with you in the room while scanning.