Endocrine Abstracts

The aim of our study was to evaluate the influence of rhTSH on the efficacy of radioiodine therapy (RIT) in patients with toxic nodular goitre(TNG) with low RAIU. Materials and methods: The study was performed on 30 patients with TNG (22 female and 8 male aged 45–78years) referred for 131I therapy. All patients had low RAIU (16–18%) 24 hours after a diagnostic dose of I-131 (4 MBq). All the patients received a single intramuscular dose of 0.05 mg rhTSH (thyrogen). 24 h later diagnostic dose of 131I was administered and thyroid scan with RAIU after 24 and 48 h was estimated. Therapeutic dose of 131I was given on the third day of rhTSH administration. Serum levels of TSH, fT4 and fT3 were determined, 24 h, 72 h after rhTSH administration and on the 3rd day after RIT. The therapeutic activity of 131I calculated by Marinelli’s formula and ranged between 280 and 600 MBq. The absorbed dose ranged between 160 and 300 Gy. Follow up control was done every 6 weeks. Thyroid ultrasound, and thyroid scan were done again after12 months of RIT

Results: A significant increase (2–8 fold) in 24hr RAIU was observed after rhTSH administration. The distribution of radioiodine was more homogeneous 48 hours after rhTSH injection. After 12 months 93% of patient were in euthyroidism and 7% (2 patients) develop hypothyroidism. After six months the mean reduction in goitre volume was 20% and 45–50% after twelve months. The medium therapeutic activity of 131I was 280 Mob. Conclusions: Pre-treatment with rhTSH reduce the therapeutic dose of 131I by 50–58% without compromising the result of thyroid volume reduction. rhTSH makes RIT of TNG more effective in the patients with low RAIU.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector