Multy-factors Related To The Therapeutic Efficacy Of¹³¹I In Hyperthyroidism

Objective: The aim of this study was to investigate the factors thatinfluence the effect of¹³¹I therapy on hyperthyroidism.Methods: The study was performed retrospectively on a group of200patients （25males,16females; mean age,52.3; age range,14-72years） fromNuclear Medicine Department of The First Hospital of Jilin University with thediagnosis of hyperthyroidism. The following information was recorded atdisease onset: gender, age, duration of disease, family history ofhyperthyroidism and medication history. Anti-thyroid drugs and seafood werestopped at least2weeks before treatment；All patients underwent detailedphysical examination and routine blood test. Thyroid gland size and rigiditydetermined by palpation. Thyroid gland weight was measured by SPECT scansan ultrasound examination. All patients have performed thyroid function （TSH,FT3,FT4） and thyroid autoantibodies （TGAb, TMAb） tests．Radioiodine uptakescan using¹³¹I before radioactive iodine treatment. A calculated dose of¹³¹I wasgiven to all the patients who were followed within twelve months． The data ofthyroid weight expressed as means±standard deviation. Associations betweenvariables and comparison of proportions were done using t test, P values P<0.05were considered significant （SPSS13software for Windows）.Results:1. The oral dose of¹³¹I was230.8MBq （111MBq⁵55MBq）. Followed up,145patients （72.5%） appeared euthyroid,17patients （8.5%）werestill hyperthyroidism. While,50patients were appeared hypothyroidism,among them12patients were transient hypothyroidism,38patients （19%） werepersistent hypothyroidism.2、Among the145patients with euthyroid after¹³¹Itherapy, the recovery rate of none and I°goiter were90.5%and88.8%，themean dose of¹³¹I was （178.3±13.5） MBq; while the recovery rate of II°andIII°goiter were55.8%and30.8%, the mean dose of¹³¹I was （278.8±73.0）MBq. Among the145patients with euthyroid, the curative ratio of the tender,moderate, rigid goiter were96.5%、61.3%and38.2%, respectively, the meandose of¹³¹I were （189.8±24.8）MBq,（179.5±22.4）MBq and （173.6±17.3）MBq, respectively.3. The thyroid weight of the patients before¹³¹Itherapy were56.3±28.2（17.8¹15.0）g （RI） and50.2±18.7（14.2¹05.7）g （US）,there was no significant difference between RI and US. After¹³¹I therapy thethyroid weight were28.9±12.8（6.0⁴9.2）g （RI） and23.5±7.9（5.6⁴6.9）g.The reduction percentage of the thyroid weight was （43.6±19.7）%by RI, and（53.2±17.6）%by US. Reduction of thyroid weight was correlated with thatbefore therapy （determined by US, t=0.49, P<0.01）4. Before¹³¹I therapy therewere73patients with serum TGAb positive （normal<30%）, the mean valuewas75.5±20.3%（40.0%⁹5.2%）,70of73patients with serum TMAbpositive （normal<15%） simultaneously, the mean value was58.2±20.3%（35.0%⁹0.1%）. In the TGAb positive group, there were19patients （26.0%）appeared hypothyroidism, while9patients （7.1%） appeared hypothyroidism in the TGAb negative group, there were significant difference between TGAb（TMAb） positive and negative groups.Conclusion:①¹³¹I therapy can treat hyperthyroidism effectively.②Closerelationship were found between¹³¹I therapeutic effect and rigidity of goiter, andtype of goiter.③The thyroid weight of the hyperthyroidism is significantlyreduced after the first dose of¹³¹I. The reduction of thyroid weight is correlatedwith the initial thyroid weight.④TGAb, TMAb play some role inhypothyroidism development.