For the SLN biopsy procedure, you will go to the operating room and undergo SLN mapping and biopsy under general anesthesia. A small amount of Tc99m-Sulfur colloid will again be injected into the eyelid around the tumor(s), to help the doctor find any possible SLNs. If you have your tumor removed earlier, the small amount of Tc99m-Sulfur colloid will be injected into the eyelid around the area of earlier tumor site. Then you will have the SLN biopsy. To collect the SLN biopsy, the doctor will make a small incision into the tissue over the lymph nodes that have picked up the Tc99m-Sulfur colloid. The lymph nodes will then be removed and tested for signs of metastatic disease.