Lymphoscintigraphy

Lymphoscintigraphy is a nuclear medicine procedure to imaging lymphatic system. This is most used technique for lymphatic mapping in breast cancer or cutaneous melanoma. A small amount of radiotracer is injected around cancer and transported by the draining lymphatics to visualize the sentinel node with a gamma camera (the first lymph node receiving the lymph drainage from a cancer). Then, in operating room, surgeon uses a handheld gamma probe to identify radioactive sentinel node for biopsy. Lymphoscintigraphy may also be used for clinical management of lymphedema or to predict the risk of secondary lymphedema in patients undergoing surgery for cancer and external beam radiation therapy. Currently, rest/stress intradermal lymphoscintigraphy is the favorite imaging test for functional assessment of the lymphatic system. After intradermal tracer injection in the foot or hand, the patient performs a quick and a long muscular exercise, allowing a better and complete visualization of superficial and deep lymphatic pathways and regional lymph nodes in shorter time. Lymphoscintigraphy can evaluate dynamic response after muscular exercise as reduced flow, areas of blockage, and dermal backflow. This functional imaging helps to define the lymphatic problem and the possible response to treatment or the direction of treatment.