This book assess the value of NM, and TFT, Scintigraphy, US and biopsy in the detection of nodules and to determine the prevalence of thyroid nodules among patients with thyroid goiter. Methods and technique of staff and patient dosimetry during thyroid scan was discussed in depth. Measure the normal Sudanese thyroid volume using US in healthy population which could be used to define goiter and to establish the normal levels of thyroid hormones concentration The palpation alone, especially in the adolescent age, is mostly unsuitable in order to differentiate between normal and early goiter development. Consequently sonography is essential in epidemiological studies of goiter incidence ,The high rate of malignancy appearance could be attributed to the delay of patient’s reference to clinical units, no correlation was found between thyroid volume and body thyroid related hormones. Thyroid volume is greater in males than females.