Sentinel lymph node mapping in melanoma with technetium-99m Dextran

Purpose: The aim of this work is to evaluate the capability of Tc99m B Dext ran as a lymphoscintigraphic agent in the detection of the sentinel node in skin lesions. Materials and Methods: Forty-one patients with melanomas (39) and Merkel ce ll tumors (2) had perilesional intradermal injection of Tc99m-Dextran 2 hou rs before surgery. Serial gamma camera images and a handheld gamma probe we re used to direct sentinel node biopsy. Results: In 39/41 patients, lymph channels and 52 sentinel nodes (one to th ree sentinel nodes/patient) could be visualized. In one patient, with a dor sal melanoma, no lymph channels or lymph nodes could be demonstrated on the images and only minimal radioactivity was found in the regional nodes with the probe. Another patient with a facial lesion failed to demonstrate lymp h channels or nodes. No adverse reactions were observed. Conclusion: Tc99m-Dextran provided good definition of lymph channels and se ntinel node localization, without the risks related to the use of potential ly hazardous labeled materials of biological origin.