Lymphoscintigraphy is an examination of the lymphatic vessels and nodes which involves an injection of a water-based radionuclide to view the lympatic tissues.  The flow of this substance is traced with a gamma camera and a computer is used to create images of the lymph flow and to calculate the speed of uptake. 
Patient Information
Lymphoscintigraphy is one of the safest and most accepted method of diagnostic testing for lymphedema.  This diagnostic test is also the method used to identify the sentinel node in the a sentinel node biopsy.