Prior to the sentinel lymph node biopsy procedure, you will receive 4 injections of a radioactive material just under the skin in the area near the melanoma tumor. Pictures will be taken for 1 hour to show the flow of the material through the lymph nodes. A doctor will then mark your skin at the sentinel node sites. These marks will be used by your doctor during surgery.
Lymphoscintigraphy is also used to test if a patient has lymphedema, a swelling of leg or arm that can occur due to surgical removal of the lymph nodes.