Lymphoscintigraphy is a specialist imaging test used to assess how well the lymphatic system is working. The lymphatic system is a network of vessels and lymph nodes that helps drain excess fluid from the tissues, supports the immune system and helps maintain fluid balance in the body.

During the test, a very small amount of radioactive tracer is injected just under the skin, usually in the hands or feet depending on the area being investigated. A special camera then takes images as the tracer moves through the lymphatic vessels. This allows clinicians to see whether lymph fluid is draining normally, moving slowly or becoming blocked.

For people with lymphoedema, lymphoscintigraphy can help confirm whether swelling is linked to poor lymphatic drainage. It can also show which parts of the lymphatic system are affected and whether the lymphoedema is primary, meaning related to how the lymphatic system developed or secondary, meaning caused by damage such as surgery, radiotherapy, infection, injury or cancer treatment.

The results can support diagnosis, guide treatment planning and help healthcare professionals decide on the most appropriate management approach. This may include compression therapy, skin care, exercise, manual lymphatic drainage, specialist lymphoedema therapy or referral for further assessment where needed.

In summary, lymphoscintigraphy is used to:

• Assess how well lymph fluid is draining through the lymphatic system.
• Help confirm a diagnosis of lymphoedema.
• Identify areas of slow drainage, blockage, or abnormal lymph flow.
• Help distinguish between primary and secondary lymphoedema.
• Support treatment planning and ongoing management.
• Provide useful information when symptoms are unclear or when swelling may have more than one possible cause.