¹⁷⁷Lu of specific activity ~100 –110 TBq/g and radionuclidic purity of ~100% was obtained by irradiation of enriched Lu ₂O₃ (60.6% ¹⁷⁶Lu) target for 7 days at a thermal neutron flux of 3 ×10¹³n/cm²/sec. The ¹⁷⁷Lu labeling of a macrocyclic bifunctional chelating agent viz. 1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid (DOTA) has been extensively studied. Lanreotide, [β-naphthyl-Ala-Cys-Tyr-D-Trp-Lys-Val-Cys-Thr-NH₂] a disulfide-linked cyclic octapeptide and a somatostatin analog, reported to bind with a wide variety of tumors expressing somatostatin receptors, was conjugated with DOTA. The peptide-BFCA conjugate was characterized with the help of high-resolution two-dimensional proton NMR spectroscopy. The ¹⁷⁷Lu labeling of the DOTA-lanreotide conjugate has been standardized to give a radiolabeling yield of 85%. The tracer showed specific binding with A-431 human epidermoid carcinoma and IMR-32 human brain neuroblastoma cells.