Measurement of radiation dose to the eye lens in non-enhanced CT scans of the brain

Abstract

Radiation can have undesirable effects on the eye, including a gradual loss of vision. Unnecessary radiation can reach the eye lens during non-enhanced computed tomography (CT) scans of the brain. The International Commission on Radiological Protection states the threshold for acute and chronic eye lens exposure is 500 mGy and the equivalent dose limit for the eye lens for public exposure is 15 mSv per year. Therefore, we measured the direct radiation dose to the eye lens during head CT scans using NanoDots in 216 adults. The mean absorbed dose to both eyes was 33.62 mGy (standard deviation ±12.442). The averages for the other variables were: tube current-time product: 260 mAs; dose-length product: 708 mGy cm and CT dose index: 35.5 mGy. Our findings encourage further study of radiation exposure and modifications in CT imaging protocols.