OBJECTIVES: I. Determine the maximum tolerated dose of yttrium Y 90-SMT 487 in patients with recurrent malignant neoplasms that prove positive for somatostatin receptors. II. Determine the safety and lifetime serious adverse event profile of this regimen in these patients. II. Determine the antitumor effect and the effect of repeated administrations on the renal excretion pharmacokinetics of this regimen in these patients.