The study conducted on Lewis rats carrying pancreatic tumor CA 20948 expressing SST-R2 affirmed that: (1) [90Y]Y-DOTATOC binds rapidly to the tumor of rats; (2) 24 h after administration, the ratio of radiopharmaceutical concentration in the tumor to blood is equal to 49.14; (3) a single administration of 10 mCi/kg of [90Y]Y-DOTATOC is able to determine a complete response in 5/7 experimental animals, with no signs of recurrence disease in the following eight months. The gene discussed is SSTR2; the disease is neoplasm.