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Am J Nucl Med Mol Imaging 2012;2(3):362-385
Review Article
False-positive uptake on radioiodine whole-body scintigraphy: physiologic and 
pathologic variants unrelated to thyroid cancer
Jong-Ryool Oh, Byeong-Cheol Ahn
Department of Nuclear Medicine, Kyungpook National University School of Medicine and Hospital, Daegu, South Korea
Received May 17, 2012; accepted June 22, 2012; Epub July 10, 2012; Published July 30, 2012
Abstract: Radioiodine whole-body scintigraphy (WBS), which takes advantage of the high avidity of radioiodine in the functioning 
thyroid tissues, has been used for detection of differentiated thyroid cancer. Radioiodine is a sensitive marker for detection of thyroid 
cancer; however, radioiodine uptake is not specific for thyroid tissue. It can also be seen in healthy tissue, including thymus, breast, 
liver, and gastrointestinal tract, or in benign diseases, such as cysts and inflammation, or in a variety of benign and malignant 
non-thyroidal tumors, which could be mistaken for thyroid cancer. In order to accurately interpret radioiodine scintigraphy results, one 
must be familiar with the normal physiologic distribution of the tracer and frequently encountered physiologic and pathologic variants 
of radioiodine uptake. This article will provide a systematic overview of potential false-positive uptake of radioiodine in the whole body 
and illustrate how such unexpected findings can be appropriately evaluated. (ajnmmi1205003)
Keywords: Differentiated thyroid cancer, radioiodine, I-131, I-123, whole-body scintigraphy, false-positive, physiologic uptake, 
pathologic uptake
Address all correspondence to:
Dr. Byeong-Cheol Ahn
Department of Nuclear Medicine
Kyungpook National University School of Medicine and Hospital
Daegu, South Korea. 50, Samduk 2-ga
Chung gu, Daegu, South Korea 700-721.
Tel: 82-53-420-5583; Fax: 82-53-422-0864
E-mail: abc2000@knu.ac.kr