what substance do the lymph nodes produce
URL of this page: //medlineplus.gov/ency/article/003798.htm. A lymphangiogram is a special x-ray of the lymph nodes and lymph vessels. Lymph nodes produce white blood cells (lymphocytes) that help fight infections. The lymph nodes also filter and trap cancer cells. The lymph nodes and vessels are not seen on a normal x-ray, so a dye or radioisotope (radioactive compound) is injected into the body to highlight the area being studied.