Radioguided surgery is an innovative means by which a radionuclide is used to preoperatively image and intraoperatively visualize a structure of interest to the surgeon for excisional biopsy. This technology has allowed a cost-effective, highly specific means by which to locate a structure (usually a lymph node) and access it for pathologic analysis. The result of radioguided surgery is increased specificity in tissue obtained for biopsy, minimal access incisions, and the reduction of inpatient hospital utilization. Radioguided surgery should not be confused with radiosurgery, which is the stereotactic application of external beam radiation, usually for intracranial tumors.

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, or the affinity of both. Current clinical applications of radioguided surgery are: radioimmunoguided surgery (RIGS) for colon cancer, sentinel-node mapping for malignant melanoma (which has become state-of-the-art), sentinel-node mapping for breast, vulvar and penile cancer, and detection of parathyroid adenoma and bone tumour (such as osteid osteoma). Although the same gamma-detecting probe 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 bone. The mode of injection also differs, but there are some common principles of gamma-guided surgery. RIGS enables the surgeon to corroborate tumour existence, find occult metastases, and assess the margins of resection; this may result in a change on the surgical plan. Sentinel lymph-node (SLN) scintigraphy for melanoma guides the surgeon to find the involved lymph nodes for lymph-node dissection. SLN for breast cancer is being investigated with promising results. This procedure has also changed the outlook of lymph-node pathology by giving the pathologist designated tissue samples for more comprehensive examination. Gamma-guided surgery will result in more accurate and less unnecessary surgery, better pathology and, hopefully, in better patient survival.