Interstitial lymphoscintigraphy for lymphatic mapping in surgical practice and research.

Lymphoscintigraphy is a nuclear medicine technique that gives morphologic and functional information about the lymphatic system. The size of radiopharmaceutical used is a critical factor for it to have acceptable characteristics of uptake by the lymphatics and migration to lymph nodes. A small particle (10-100 nm) with opsonins or a unique surface is required for uptake by lymph-node macrophages. It can be prepared for application with a simple filtering process producing a predictable size distribution and number of particles for the scan. The radiation dose is safe for the patient and staff. Technetium-99m sulfur colloid is readily available and approved for use. The injection can be performed by anyone with certification in handling radiopharmaceuticals. Imaging is done with standard gamma cameras available in any nuclear medicine department. The addition of the hand-held gamma probe adds a new dimension to application of the technique of lymphatic mapping and identification of areas that retain radiopharmaceuticals. Its use is simple and reproducible. The application of lymphoscintigraphy and gamma-probe localization techniques in clinical medicine is best exemplified with the now commonly used sentinel node approach to staging and treating intermediate-thickness malignant melanoma. A number of other malignant diseases such as breast cancer may have their treatments altered with these techniques as well. As a research and diagnostic tool, the creative application of interstitial lymphoscintigraphy can give important qualitative information regarding the morphology and physiology of the lymphatic system. The development of these techniques for surgical research and practice is reviewed.