A recent study examined both radiation interventionists and technicians to ascertain the risk of developing radiation cataractogenesis as a result of providing interventional radiation therapy. The study showed a positive correlation between increased occupational radiation dose and the propensity to develop posterior eye changes, including increased lens opacity.
Interventional radiation (IR) is a critical component of both diagnosis and treatment of several pathologies. Given the large number of images taken and lengthy exposure times of this form of therapy, both the patients and medical staff are exposed to high doses of ionizing radiation. The eye lens is one of the most radiosensitive tissues in the body, and is therefore exceedingly susceptible to ionizing radiation. The damage that occurs from excess exposure to radiation includes accumulation of dead lens cells, which results in an increase in lens opacity. The researchers sought to collect epidemiological data to analyze the risk of increased lens opacity in medical staff that perform treatments utilizing IR.
The researchers examined lens opacity, using lens opacity grading, of 81 Iranian IR medical staff, including staff from adult IR, pediatric IR, and electrophysical IR labs. The major finding of this analysis was a “significant positive correlation between years of working experience and effective dose of the lens in all subjects,” with interventionists being slightly more susceptible than technicians. In other words, the more years of occupational radiation exposure and/or the more frequent the occupational radiation exposure (i.e. number of procedures per week), the higher the risk of developing increased lens opacity. However, this study did not analyze the propensity for this enhanced risk of increased lens opacity to lead to medically diagnosed radiation cataractogenesis.
Strikingly, the researchers showed that the incidence of lens opacity was over ten times higher for medical staff exposed to IR when compared to medical staff that are not. Overall, medical staff that worked in adult intervention labs experienced the highest degree of lens opacity (around 88%), with researchers attributing this enormous increase to the lengthy procedures required in adult interventions.
The findings supported by this study seem to suggest that the ICRP recommended occupational dose limit (threshold) should be much lower, given that the radiation-associated opacities examined in this study and others occurred at doses lower than those recommended by the ICRP.
Perhaps the most distressing finding was the overall lack of usage of ocular protective equipment during administration of IR treatment. Alarmingly, only 30% of the study participants used appropriate ocular protective equipment. The researchers believe that strict guidelines enforcing the use of ocular protective equipment could greatly reduce the propensity of IR staff to develop increased lens opacity.
