Dr. Dong Gyu Na completed residency training in the department of radiology at Seoul National University Hospital and became a certified member of the Korean Board of Radiology in 1995. He has worked in Thyroid, Head and Neck Radiology section since 1996 and he is a radiologist specialized in thyroid imaging and intervention. He is a clinical professor and the director of thyroid radiology section at Gangneung Asan Hospital. Dr. Dong Gyu Na served as a president of Korean Society of Thyroid Radiology (KSThR) from 2010 until 2014 and he is the chair of clinical guideline committee of KSThR at present. He has operated outpatient thyroid clinic since 2008 and his major clinical and research field is the imaging diagnosis and interventional treatment of thyroid cancer.