Quantification of scatter radiation from radiographic procedures in a neonatal intensive care unit

Background: In a neonatal intensive care unit (NICU), preterm infants are often exposed to a large number of radiographic examinations, which could cause adjacent neonates, family caregivers and staff members to be exposed to a dose amount due to scatter radiation.

Objective: To provide information on scatter radiation exposure levels in a NICU, to compare these values with the effective dose limits established by the European Union and to evaluate the effectiveness of radiation protection devices in this setting.

Materials and methods: Radiation exposure levels due to scatter radiation were estimated by passive detectors (thermoluminescent dosimeters) and direct dosimetric measurements (with a dose rate meter); in the latter case, an angular map of the scatter dose distribution was achieved.

Results: The dose due to scatter radiation to staff in our setting is approximately 160 μSv/year, which is markedly lower than the effective dose limit for workers established by the European Union (20 mSv/year). The doses range between 0.012 and 0.095 μSv/radiograph. Considering a mean hospitalization period of 3 months and our NICU workload, the corresponding scatter radiation dose to an adjacent patient and/or his/her caregiver is at most 40 μSv.

Conclusion: For distances greater than 1 m from the irradiation field, both scatter dose absorbed by a staff member during a year and that by an adjacent patient and/or his/her caregiver during hospitalization is less than 1 mSv, which is the exposure limit for public members in a year.