Detection of metastatic thyroid carcinoma after the administration of a therapeutic dose of 131-iodine.

A patient with thyroid cancer is described whose metastases were detected only after the administration of a large therapeutic dose of 131 Iodine. This suggests that very high doses of 131 Iodine might permit diagnoses of metastatic lesions not otherwise detected. This phenomenon may be explained by the improved counting statistics which occur with the use of a higher dose of the isotope. In such cases, exceedingly high doses of 131 Iodine might be necessary for successful tumor ablation.