The aim of this trial was to evaluate in developing countries from different regions the diagnostic performance of 99m Tc-sestamibi scintimammography (SM) in palpable breast lesions and to verify the clinical usefulness of a joint evaluation with mammography and SM. Methods: From 10 countries, a total of 238 patients with palpable breast masses (n= 245) were included in this prospective multicenter trial. Prone SM was performed 10 min and 60–90 min (157 patients) after injection using an isotime acquisition of 10 min. Mammography