To determine how often thyroid scanning correctly predicts the diagnosis of thyroid abnormalities, 59 patients who had thyroid surgery were examined with the scintillation camera shortly before operation. To improve the intrinsic resolution of the system, the thyroid gland was magnified two to three times normal size by using a pinhole collimator. With the higher-quality images, multinodular thyroids were correctly detected in 65% of the patients. Twenty-five were interpreted as solitary nodules; two were thought to be normal glands; one was diagnosed as diffuse hyperplasia. In only 39 (22%) of the patients with multinodular goiter were the nodules palpable. The remainder were diagnosed clinically as solitary nodules. Of 26 solitary nodules, 20 were seen in the images. When solitary nodules were not visible in the images, they were either small (<0.5 cm in diameter) or in the isthmus.