Thyroid scanning of the patient with history of childhood irradiation.

The utilization of external radiation for the treatment of benign conditions of the head and neck is no longer employed because of the discovered association of local irradiation with the development of thyroidal cancer. This practice was widespread until two or three decades ago. It is also known that there is a very long latent period between previous radiation and the development of thyroid cancer. In consequence, a substantial number of persons can be expected to develop thyroidal malignancy each year until the turn of the millenium, and even later. If this association is real, then early diagnosis is especially important because of the excellent therapeutic results that can be obtained with early diagnosis. Physical examination performed on a regular basis is the most important single diagnostic aid. A statistically significant improvement in sensitivity is obtained when palpation is performed in conjunction with radioisotopic thyroid scanning. The scan helps by identifying areas of abnormality and--even more importantly--by allowing distinction of those nodules which are hypofunctioning and thus more likely to be malignant.