Objective To analyses the clinical data of ¹³¹I in treating youngsters with Graves disease, and to explore the effective dose range which is appropriate for Chinese youngsters with Graves disease.

Methods Two hundred and thirty-four youngsters with Graves disease were selected in this study, their ages were between 8 and 17, the average quality of their thyroids was (59.0±16.5)g. According to the absorbed dose of ¹³¹I per gram of thyroid gland, 234 patients were divided into five groups: A: 1.11- < 1.48 MBq/g, B: 1.48- < 1.85 MBq/g, C: 1.85- < 2.22 MBq/g, D: 2.22-2.59 MBq/g, E: >2.59 MBq/g. The therapeutic effect was evaluated by observing after treatment. And calculate the recovery rate, the improvement rate and the incidence rate of hypothyroidism.

Results ① One hundred and fifty-two(64.95%) patients were cured, 56(23.93%) were much better than before and 26(11.11%) were hypothyroid. The therapeutic effect of group B was the best in all groups. ②The recovery rate: there was no significant difference between group B, group C and group D(χ²=2.68, P>0.05). The recovery rate of group B was better than group A and group E(χ²=10.20 and χ²=5.49, P < 0.05). The recovery rate of group A was the lowest. ③The improvement rate: There was no significant difference between group B, group C, group D and group E (χ²=1.94, P>0.05). The improvement rate of group A was the highest (χ²=8.74, χ²=6.68, χ²=7.01 and χ²=11.12, P < 0.05). ④The incidence rate of hypothyroidism: There was no significant difference between group A, group B, group C and group D (χ²=2.71, P>0.05). Group E had the highest incidence rate of hypothyroidism(χ²=12.36, χ²=11.58, χ²=9.37 and χ²=4.36, P < 0.05).

Conclusions Using ¹³¹I is a safe and effective therapeutic approach for youngsters with Graves disease. We suggest the absorbed dose range of ¹³¹I per gram of thyroid gland is 1.48-2.59 MBq/g, which can obtain the better therapeutic effect and can't increase the incidence rate of hypothyroidism.