Variables Number (%)
Age
Age < 50 years
 Age > 50 years
Mean 50.5 years (range:23-66) SD12.01
10 (55.6%)
  8 (44.4%)
Gender

Male
Female


10 (55.6%)
  8 (44.4%)
T Stage

T3
T4
3 (16.7%)
15 (83.3%)
N Stage

N0
N1
N1a
N1b


4 (22.2%)
14 (77.8%)
8 (44.4%)
6 (33.3%)
Histology

Papillary
Follicular


17 (94.4%)
1 (5.6%)
Pathological T size

Less than 4cm
More than 4cm


8 (44.4%)
10 (55.6%)
Multifocality

Yes
No


10 (55.6%)
8 (44.4%)
Lymphovascular invasion

Yes
No


7 (38.9%)
11 (61.1%) 
Surgical margin status

Positive
Negative


14 (77.8%)
4 (22.2%)
Extrathyroid extention

Yes
No
17 (94.4%)
1 (5.6%)
Type of surgery

Total thyroidectomy
Subtotal thyroidectomy


16 (88.9%)
2 (11.1%)
Neck dissection

Yes
No


7 (38.9%)
11 (61.1%)
Before IMRT Tg level (ng/ml) 59.7 (1-248.9) SD 83.9
131I therapy cumulative dose (mCi) 159± 30.9
SD= standard deviation, Tg= serum Thyroglobulin, mCi= milliCurie
Table 1: Patient characteristics.