This paper deals with the first dose to give 131 I for ablating the remanant thyroid tissue in 39 cases of thyroid cancer. The patients were divided into two groups with and without the extrathyroid uptake. The relationship between the effectiveness and dosage has been discussed. Finally it was determined that in order to get an optimal 131 I doses and to achieve complete ablation
the size of remanant thyroid
the number of metastatic fool etc could affect the final result and should be considered.