Clinical applications of gamma-detection probes - radioguided surgery

Radioguided surgery (RGS) is a surgical technique that enables the surgeon to identify tissue "marked" by a radionuclide before surgery, based on the tissue characteristics, the radioactive tracer and its carrying molecule, o r the affinity of both. Thus, yet another tool has been added to the inspec tion and palpation traditionally used by the surgeon, Current clinical appl ications of radioguided surgery are: radioimmunoguided surgery (RIGS) for c olon cancer, sentinel-node mapping for malignant melanoma (which has become state-of-the-art), sentinel-node mapping for breast, vulvar and penile can cer, and detection of parathyroid adenoma and bone tumour (such as osteid o steoma), Although the same gamma-detecting probe (GDP) may be used for all these applications, the carrier substance and the radionuclide differ. MoAb and peptides are used for RIGS, sulphur colloid for sentinel-node mapping, iodine-125 for RIGS, technetium-99m for sentinel node, parathyroid and bon e. The mode of injection also differs, but there are some common principles of gamma-guided surgery. RIGS enables the surgeon to corroborate tumour ex istence, find occult metastases, and assess the margins of resection; this may result in a change on the surgical plan. Sentinel lymph-node (SLN) scin tigraphy for melanoma guides the surgeon to find the involved lymph nodes f or lymph-node dissection. SLN for breast cancer is being investigated with promising results. This procedure has also changed the outlook of lymph-nod e pathology by giving the pathologist designated tissue samples for more co mprehensive examination. Gamma-guided surgery will result in more accurate and less unnecessary surgery, better pathology and, hopefully, in better pa tient survival.