Risk factors for eye lens opacity in nuclear medicine workers - An overview

Workers occupationally exposed to ionizing radiation, including nuclear medicine workers, are one of the groups at higher risk of a radiation cataract. Reducing the lens dose limit from 150 mSv/year to 20 mSv (averaged over defined periods of 5 yrs, or 50 mSv in 1 yr) makes other risk factors less obvious. The presented work is a review of the literature not only in the scope of the most obvious risk factor in this occupational group - ionizing radiation, with special attention given to issues specific to nuclear medicine (e.g. the variety of radionuclides or manual performing of procedures), as well as the difficulties related to the routine monitoring of eye lens exposure. Moreover, the paper presents several other risk factors that may play a key role in modulating damage to the eye lens. These include age, exposure to UV radiation, oxidative stress, genetic factors and dietary nutrient intake. An overview of all known molecular and biophysical mechanisms that imply the modulation of the cataract-related mechanism most often focus on radiation protection, has been given. The prepared review is the basis for the possibility of developing new studies aimed to introduce new protocols based on the intake of specific nutrients that could reduce the effects of the dose absorbed by the lens and, consequently, reduce the onset of cataracts in an employee involved in nuclear medicine practices.