Lead-in study I: SLNB simulations using the GAPS simulator

Standard practice requires the use of Tc–labeled radiopharmaceuticals for SLNB. The presence of F-FDG in study subjects results in greater than normal background signal being detected by the handheld gamma probe used for SLNB, due to the down-scatter of 511keV Fluorine-18 (F) gamma photons into the Tc energy window. This cross-talk background could potentially hinder detection of low-activity SLNs. To assess the F cross-talk and to determine the activity of Tc-nanocolloid required to successfully perform standard of care SLNB in patients undergoing F-FDG CLI-guided surgery, two lead-in studies were conducted prior to commencing the CLI study.