Methodological Aspects of Lymphatic Mapping: Radiopharmaceuticals, Multimodal Lymphatic Mapping Agents, Instrumentations

This chapter reviews the main features of the radiopharmaceuticals used for lymphoscintigraphy and the factors that affect their performances. Since radiopharmaceuticals for lymphoscintigraphy are injected interstitially, extracellular matrix composition and solute proprieties have significant influence on the capability of radiopharmaceuticals to move through the interstitium into the lymphatic vessels and until the lymph nodes. Weight, size, shape, and charges are the main factors affecting the final results of lymphoscintigraphy. The chapter also reviews alternative techniques for lymphatic mapping using nonradioactive agents, including iodinated contrast medium for CT lymphography, gadolinium-based agents for MR lymphography, and fluorescent agents for optical lymphatic mapping. Perspectives for the use of multimodal lymphatic mapping agents are also summarized. The chapter also describes instrumentations available for sentinel lymph node localization, summarizing the main features of handheld intraoperative gamma probe as well as of portable imaging devices.