Technetium 99m P829 (99mTc P829) is a somatostatin like structure labelled with Technetium-99m. Somatostatin receptor positive tumors such as pituitary tumors, neuroendocrine tumors, and lymphomas show positive scintigraphy. Eleven patients suspected of having a pituitary mass (12 studies) were studied with 99mTc P829. Three pituitary adenoma patients (4 studies) showed positive somatostatin receptor tumor imaging. Eight negative somatostatin receptor scintigraphy were one hypothyroid induced pituitary hyperplasia, one craniopharyngioma, one normal pituitary tissue with focal hyperplasia, one ACTH secreting pituitary tumor, one GH, PRL secreting pituitary tumor post transphenoidal partial tumor removal, and no surgery in 3 patients. Finally, somatostatin receptor imaging may be useful as a tumor localizing technique in addition to conventional CT and MRI imaging and identify patients who might potentially benefit from octreotide treatment. In addition, the development of peptide analogs coupling to beta-emitting radiopharmaceutical may lead to a situation in which diagnosis peptide receptor scintigraphy can be followed by radionuclide therapy.