[en] In this report, we carried out the synthesis and evaluation of ^99mTc-lanreotide radiopharmaceutical to detect neuroendocrine tumours. Lanreotide an octapeptide, has been identified as a somatostatin analogue, bearing affinity to most of the subtypes of human somatostatin receptors. For this reason, nowadays it has gained considerable attention for development of diagnostic or therapeutic agents in the Oncology field. The peptide labelling was performed by direct method, using tartrate/phtalate-Sn²⁺ at pH 5.6. The results obtained under our experimental conditions showed the existence of an equilibrating mixture of two ^99mTc-peptide complexes, attaining yield approx. 91%. In vitro stability studies indicated that these species are stable in the presence of human serum (dissociation ∼ 1% at 24h post labelling) and undergo transchelation only when are challenged with high excess of cysteine. On the other hand, experiments using mice brain cortex membranes showed a dissociation constant value of K_D 0.12nM suggesting that the obtained species bind with high affinity and specificity to somatostatin receptors in vitro. Biodistribution studies with ^99mTc-lanreotide in healthy rats exhibited high uptake and retention in somatostatin receptor-positive tissues, as well as low dissociation of complex under physiological condition