Sentinel node scan (melanoma)

The sentinel lymph node scan is a scan to identify the first few lymph nodes into which a tumour drains. These are called sentinel nodes.

The scan is done by injecting two to four times around the excision scar with a radioactive substance. Imaging is then performed to show the lymph nodes that contain the radioactive substance. The scan does not show if the tumour has spread into the nodes. It shows only the location of the sentinel nodes.

If there is a possibility that you are pregnant or if you are currently breastfeeding please inform the department before your appointment as we will likely have to re-schedule.

Whenever possible, you should attend your appointment alone, unless you need a carer to support any additional needs.

Please allow 3 hours for your appointment.

Before the examination, a cream is applied to numb the skin around your scar and left for approximately half an hour.

Then you will be asked to change into a gown and remove any metallic objects such a bra, phone, belt or keys.

The numbing cream will be removed, and you will be taken to the scanning room and given the injections of the radioactive substance around your scar. It emits gamma rays which will be detected by a piece of equipment called a gamma camera.

You will then be asked to lie down on a table. We position the scanner around you and take images that allow the location of sentinel nodes to be identified. Occasionally images may be repeated or extra images obtained if necessary. All images will be checked before you leave the department.

After the appointment you can resume all usual activities. Eat as normal and keep well hydrated, but please remember to follow the instructions for your surgery.

If you have young children or pregnant friends/family please limit close contact with them for the rest of the day. You can be in the same room but avoid sitting close to each other for long periods. This is to avoid them receiving any unnecessary radiation exposure.

The results of your scan will be made available to your surgeon in time for your surgery.

The radioactive tracer administered will expose you to a small amount of ionising radiation, consistent with the desired diagnostic outcome.

The risks are very low and the benefits of having the results from the Sentinel node scan greatly outweigh the risk.