The current literature about the results of SLNB technique has not yet considered the influence of the addition of SPECT-CT imaging (standard approach in our institute since more than 3 years) to planar imaging. In this study, we propose to analyse in a prospective manner the contribution of SPECT-CT: contribution of the analysis of the signal intensity of active lymph nodes on SPECT slides to define a resection threshold corresponding to lymph nodes at risk of being pN+, accuracy for the anatomic localization, better accuracy of the number of SLN on the SPECT-CT versus planar image, better definition of the number of lymph nodes (to be analysed on the CT) covered by a radioactive spot (we have already observed 3 adjacent lymph nodes under one only active spot).