The standard of care in breast cancer surgery includes identification and assessment of the sentinel lymph node (SLN). At the present time, SLN mapping utilizes a gamma ray-emitting radiotracer and/or a blue dye. Radiotracers provide sensitive detection of SLNs, but require involvement of a nuclear medicine physician, vary widely in transit time depending on the agent employed, can be difficult to localize with a handheld gamma probe, and expose both patient and caregivers to ionizing radiation. Blue dyes, such as isosulfan blue, cannot be seen easily through skin and fat, but can aid in definitive identification of the SLN when the handheld gamma probe gives ambiguous results. Finally, the learning curve associated with expertise in the SLN procedure is quite long using currently available techniques.