In the United States it refers to a board certified endocrinologist physician, who is either a full time academic with multiple responsibilities beside thyroid patient care, or a clinical thyroidologist.
[citation needed] In many European countries, not only endocrinologists, but also nuclear medicine specialists work as clinical thyroidologists focusing on diagnosis and treatment of thyroid disease.
[1][2] The American Association of Clinical Endocrinologists (AACE) developed the Endocrine Certification in Neck Ultrasound (ECNU) program.
[3] ECNU is a professional certification in the field of neck ultrasonography for Endocrinologists, Thyroidologists, and Thyroidology practices.
Physicians and medical practitioners who hold the ECNU professional certification are highly specialized thyroidologists in the field of neck ultrasonography.