Cushing syndrome (CS), a fatal disease, is suspected in many thousands of patients each year, but confirmed in only a fraction of these. This project seeks to identify accurately which patients have Cushing syndrome, to define the etiology of their disease and to treat it optimally. A major initiative in the past year has been to determine whether octreotide scintigraphy (using a 6mCi dose of 111Indium pentetreotide) is a useful imaging modality for the localization of ectopic ACTH-secreting tumors. 18 consecutive patients with presumed ectopic ACTH secretion received octreotide scintigraphy as well as CT and MRI. Tumor was detected initially in 7/18 patients, and in 3/18 during follow-up. No ACTH-secreting tumor was detected by octreotide scintigraphy when CT/MRI were negative, although octreotide confirmed the presence of tumor in 6/10 patients. 17 of 40 scintigrams were abnormal. Of these, 10 represented tumor, 6 were falsely positive, and one non-ACTH-secreting hepatic lesion was detected by CT also. We conclude that octreotide may be a useful adjunctive modality, but is not a significant advance over conventional imaging, and should not be used alone for the localization of these tumors.An additional initiative was to evaluate the utility of salivary cortisol as a screening test for Cushings syndrome. Salivary cortisol has a high diagnostic accuracy for the identification of Cushings syndrome in adults. - Human Subjects