What is a sentinel lymph node?
Lymph is fluid that escapes from blood vessels into the tissues. It travels in a network of lymphatic vessels that eventually returns this fluid to the blood stream. Lymph nodes are glands or filters found along these lymphatic vessels. They contain white blood cells and other immune system cells. Lymph nodes trap bacteria and viruses, as well as some damaged and abnormal cells, helping the immune system fight disease.
Many types of cancer spread through the lymphatic system, and one of the earliest sites they spread to is nearby lymph nodes. Groups of lymph nodes are located in the neck, underarms, chest, abdomen, and groin. A sentinal lymph node is the the first node a tumour cell would travel to if it is spreading.
What is a sentinel lymph node scan?
A sentinel lymph node scan identifies and locates the sentinel lymph node. Other tests such as ultrasound may be unable to locate the sentinel lymph node easily. This scan is usually completed just before you have surgery to remove and test the node.
As most people have surgery after the scan, you will need to follow the instructions from your doctor. This usually means fasting from midnight.
If you are pregnant or breastfeeding, make sure you let the service know.
A small injection of a radioactive tracer is given into a vein in the arm. You will then be asked to wait 15 minutes so the tracer can make its way through the body and to the thyroid gland. Pictures will then be taken with a special camera. This scan takes about 30 minutes and you will be required to lay still during the pictures and breathe normally.
There are no after-effects from having this scan. The small dose of radiation in the injection is about the same as you would get from a chest X-ray.
Once it is finished, the pictures and report will be ready in about 15 minutes. You will need to wait so you can give these to your surgeon who will need them for your operation.