Thyroid scintigraphy

Radionuclide methods in thyroidal diseases were firstly initiated after the second world war by the use of 131iodine in therapy. by the early 1950’s, radionuclide thyroid imaging studies have superseded among the diagnostic modalities when gamma scintillation detectors came into the clinical usage. in nuclear medicine, since 1980’s, single photon emission tomography (spect) and positron emission tomography (pet) imaging which came into clinical usage in 1990’s, provide three dimensional evaluation of radiotracer distribution in addition to conventional two dimensional planar scan. hybrid systems which were composed of spect and ct or pet and ct scan, produce images with improved attenuation correction and anatomic localization. spect/ct and pet/ct scans are widely performed in benign and malign thyroid diseases in current rutin practice. for many years, thyroid scan has been used in the diagnostic evaluation of several thyroid diseases. the utility of thyroid scintigraphy to characterize thyroid nodules has significantly decreased over the past decade because of the increasing use of thyroid ultrasonography and fine needle aspiration biopsy. nonetheless, the ability of nuclear medicine to assess physiology and function makes it an indispensable tool in the management of patients with thyroid disease, especially in hyperthyroidism.