REAL-LIFE RADIATION BURDEN TO RELATIVES OF PATIENTS TREATED WITH I-131 - A STUDY IN 8 CENTERS IN FLANDERS (BELGIUM)

In view of the EURATOM 96/29 [1] regulations, a prospective multicentr e study was performed to evaluate the present guidelines given to rela tives of patients treated with iodine-131 for both thyroid carcinoma a nd thyrotoxicosis, based on the real-life radiation burden. This study comprised 166 measurements carried out on a group of 94 relatives of 65 patients. All relatives wore a thermoluminescent dosemeter (TLD) on the wrist for 7 days. Sixty-one relatives agreed to wear another TLD for an additional 7 days. TLD were placed on nine patients' bedside ta bles. The eight participating centres were arbitrarily divided into th ree groups according to the period of time they advised their patients to sleep separately. Groups I, II and III respectively advised their patients to sleep separately for 0, 7-10 and 14-21 days. The median do se received by in-living relatives of thyroid carcinoma patients durin g the 14 days following hospital discharge was 281 mu Sv (doses to inf inity not calculated); the median dose to infinity received by in-livi ng relatives of ambulatory treated thyrotoxicosis patients was 596 mu Sv, as compared with 802 mu Sv for in-living relatives of hospitalised thyrotoxicosis patients. In general the children of patients received a significantly (P<0.1) lower mean dose than their partners. For thyr oid carcinoma patients, only two relatives out of 19 (10%) exceeded th e EURATOM 96/29 limit of 1 mSv/year. For thyrotoxic patients, 28% of r elatives exceeded the EURATOM 96/29 limit. but none of them were relat ives of patients who followed guidelines for 21 days. The results of t his study indicate that sleeping separately for 7 days, after a period of hospitalisation of 2-3 days, will usually be sufficient for thyroi d carcinoma patients. For thyrotoxicosis patients, up to 21 days of sl eeping separately could be necessary in order to strictly abide by EUR ATOM 96/29. Therefore, the authors propose the implementation of a non -rigid dose constraint for people who ''knowingly and willingly'' help patients treated with I-131, while still following the ALARA principl e.