Radiation ExposuretoNurses during Care of131I-MIBG Therapy for Paediatric Patients with High-risk Neuroblastoma

1583 Introduction: 131I-meta-iodo-benzyl-guanidine (131I-MIBG) therapy has been used in children with high-risk neuroblastoma. The care style in an isolation room is different depending on countries. In Japan, trained nurses care the pediatric patients in an isolation room instead of family caregivers. Control of occupational radiation exposure to nurses in caring children as low as reasonably achievable is an important issue. To determine the safety of occupational radiation exposure in nurses, we retrospectively examined radiation exposure during 131I-MIBG therapy. Materials and Methods: Sixty-two nurses who received radiation exposure during 131I-MIBG therapy were assessed for the daily percentage of total radiation exposure received using the formula, daily radiation exposure / total radiation dose × 100. The independence score of children evaluated the level of assistance required to perform necessary daily activities in an isolated room (Table1). The medical staff was educated on radiation protection and 131I-MIBG therapy, and nurses wore a lead apron and gloves, and maximized their distance from patients as much as possible. Nurses routinely used a pocket dosimeter on the lower abdomen for women and the chest for men, under the lead coat, in our isolated ward, and recorded the cumulative exposure dose. Results: Fifty-eight 131I-MIBG treatments (592 ± 111 MBq/kg) were performed in neuroblastoma patients 12 years or younger (M/F; 27 /27, mean age at 131I-MIBG treatment; 7 ± 2 years old, 2 patients received three treatments), who were isolated for 5 ± 1 days. Average total (0.36 ± 0.18 mSv; range: 0.09-0.97 mSv) and daily (0.07 ± 0.05 mSv/d; range: 0.02-0.32 mSv/d) radiation exposure to nurses per patient care. The daily percentage of total radiation exposure significantly decreased in three days after 131I-MIBG treatment (day 0, 1, and 2 was 38.2 ± 14.7 %, 26.9 ± 12.6 %, and 15.3 ± 7.1 %, respectively, Fig 1), and the average independence score was 12.2 ± 3.5 (range: 10-27) for all patients. Higher independence score was significantly related to younger patients’ age and higher daily radiation exposure in nurses (Fig 2). Conclusions: Individual exposure of the trained nurses to occupational radiation was well controlled. Nurses who care for dependent paediatric patients must be aware of the risks of radiation exposure, which can be reduced by a care system and by monitoring radiation exposure.