Abstract: The invention relates to the use of ?? emitting radiolabeled tracers for administration to a patient prior to radio-guided surgery, and to the corresponding probes designed to intraoperatively detect ?? decays from cancerous tissues so as to locate even small cancerous remnants still present after resection of the main cancerous lesions. The ?? emitting radiolabeled tracer is labeled with a radioisotope undergoing exclusively ?? decays or a radioisotope undergoing ?? decays and having no more than 10-11% of ? rays decays. The corresponding probe has an extension direction along a longitudinal axis and has one or more blocks of scintillating material, each one having a main extension parallel to the longitudinal axis and transversal dimensions smaller than 3 mm, with each of the blocks being partially shielded by a material that is inactive with respect to ?? radiation.