Table 1 Clinical information about the patients

Males [n, %]

21(25.9)

21 (40.4)

4 (36.4)

16 (25.4)

30 (37)

Age [years]

53.5 ± 16.3

67.3 ± 12.7

50.9 ± 16.4

48.6 ± 15.5

65.8 ± 12.9

Graves’ disease [n, %]

48 (59.3)

8 (15.4)

7 (63.6)

Thyroidectomy in history [n, %]

6 (7.4)

0 (0)

1 (9.1)

2 (3.2)

5 (6.2)

Thyrostatic drugs used before RAI treatment [n, %]

20 (24.7)

15 (28.8)

6 (54.5)

13 (20.6)

28 (34.6)

Beta-blockers used before RAI treatment [n, %]

19 (23.4)

19 (36.5)

2 (18.2)

11 (17.5)

29 (35.8)

Steroids used before RAI treatment [n, %]

3 (3.7)

2 (3.8)

0 (0)

4 (6.3)

1 (1.2)

Orbitopathy [n, %]

1 (1.2)

0 (0)

0 (0)

1 (1.6)

0 (0)

Thyroid volume before RAI treatment [cm³]

22.6 ± 13

41.9 ± 22.2

54 ± 31.7

24.3 ± 19.6

37.8 ± 21.3

Thyroid volume 6 months after RAI treatment [cm³]

8.4 ± 12.6

23 ± 16.4

29.7 ± 20.1

7.5 ± 9.1

21.4 ± 18.6

Diffused nodules [n, %]

39 (54.9)

44 (84.6)

5 (50)

N/A

‘Cold’ nodules

1 (1.2)

2 (3.8)

1 (9)

1 (1.6)

3 (3.7)

Iodine uptake [%]

36.4 ± 13.4

30.2 ± 11.3

54.3 ± 16.6

40.1 ± 14.3

32.2 ± 13.4

Uneven iodine distribution [n, %]

18 (22.2)

26 (50)

4 (36.4)

4 (6.3)

44 (54.3)

Inferior poles of the thyroid lobes reaching jugular incision [n, %]

3 (3.7)

10 (19.2)

3 (27.3)

3 (4.8)

13 (16)

¹³¹I⁻ dose [MBq]

638.5 ± 44.2

658.1 ± 46.4

657.8 ± 64.8

624 ± 34.9

664.9 ± 48.4

TSH concentration at presentation [μIU/ml]

1.5 ± 2.6

0.9 ± 1.7

0.6 ± 1

1.46 ± 2.9

1.08 ± 1.54

fT3 concentration at presentation [pg/ml]

4.1 ± 1.3

3.9 ± 1.6

5.6 ± 4.3

4.2 ± 1.9

4 ± 1.6

fT4 concentration at presentation [ng/ml]

5.5 ± 7.1

3.7 ± 5.1

2.8 ± 4.2

5.4 ± 6.8

4.1 ± 5.9

TSH concentration 6 months after RAI treatment [μIU/ml]

4.3 ± 5.7

2.3 ± 3.6

0.2 ± 0.25

3.9 ± 6.5

2.7 ± 3.3

fT3 concentration 6 months after RAI treatment [pg/ml]

3.5 ± 1.1

3.9 ± 1.8

4.6 ± 2.3

3.8 ± 1.7

3.9 ± 0.9

fT4 concentration 6 months after RAI treatment [ng/ml]

3.4 ± 6.2

2.2 ± 3.3

1.9 ± 2

3.7 ± 6.6

2.1 ± 3.4