Radiation protection from patients with thyroid diseases treated by ¹³¹I

Objectives To estimate the total effective dose equivalents (TEDEs) received by members of the general public in contact with patients with Graves’ disease (GD) and differentiated thyroid cancer (DTC) treated by ¹³¹I;and to recommend restricted peroids (RPs) to limit contact between the patient and a member of the general public for radiation safety.

Methods The study population consisted of 3 groups: GD group (group G) , DTC ablation group (group A ) and DTC metastases group (group M) with the mean administered activity of 248±57, 3450±78 and 6810±120 MBq, respectively. The exposure rates and equivalent exposure rates of each group were measured after ingestion. The TEDEs received by the general public were estimated using Mountford’s method under specific situations: when a patient slept together with a partner for 8 h/per day, contacted an adult relative in the range of 1 m for 6 h/per day, or co-worked with a colleague in the range of 1 m for 8 h/per day.In order to restrict the public dose to 1 mSv/year,the respective RPs were calculated by an iterative calculation.

Results The TEDEs received by a member of the public in contact with a ¹³¹I-treated patient ranged from 1.3 to 43.3 mSv if there were no restrictions.Table 1 presents the recommended PRs.

Conclusions The TEDEs received by a member of the public in contact with a ¹³¹I-treated patient may exceed 1 mSv without any restriction. It is thus necessary to establish RPs to ensure radiation safety of the public. More attention should be paid to radiation protection of GD patients.

Research Support National Natural Science Fund of China (30870724,81071184

• Download figure
• Open in new tab
• Download powerpoint

Table 1. The restricted periods (RPs) after ingestion of ¹³¹I.

The presumably administered activity of ¹³¹I for the group G, A and M is 370, 3700 and 7400 MBq, respectively.