gms | German Medical Science

Interventionalists are subjected to an elevated occupational radiation exposure. The effects to the radiation-sensitive eye lens are of eminent concern due to the possibility of radiation-induced cataracts. Their formation has long been regarded as a deterministic effect with a lens dose threshold of >500 mSv, reflected by the ICRP recommended lens dose limit of 150 mSv/a for occupational exposure [1]. However, recent research hints at the non-existence of such a dose threshold [2]. Consequently, epidemiological studies of cataracts among interventional physicians are needed. Such studies demand a robust dosimetry. However, since measured lens doses are not available for most interventionalists, one has to revert to questionnaire-based retrospective estimates. These might be accompanied by considerable uncertainties as previous studies have shown a sizable variability for the lens dose of interventional physicians. This variability is mainly rooted in the huge amount of dose-influencing parameters, which are often hard to quantify. It has already been documented that two important parameters are the treatment type and the radiation shielding method. Still, a comprehensive survey of the available literature on the eye lens exposure of interventional physicians as well as the factors affecting the dose has not yet been available and was the aim of the present work. For this purpose, an extensive literature search was conducted using the PubMed database, leading to the abstraction of eye lens dose data for interventional physicians from 84 research articles. The results show a variation of the per-procedure eye lens dose over four orders of magnitude. The arithmetic mean of these doses for all treatment types and independently of the shielding used is 0.51 mGy (standard deviation: 1.41 mGy). The median is much smaller at 90 μGy. If only procedures with eye shielding are taken into account, the arithmetic mean and median are considerably lower at 57 μGy and 25 μGy, respectively, underlining the importance of shielding. Furthermore, it is shown that cardiological interventions generally lead to lower lens exposures than other procedures. The effects of several radiation shielding devices were also quantified, revealing that they can be determined with reasonable accuracy. In summary, our literature review of eye lens dosimetry for interventional physicians evidences that a meaningful estimate of the eye lens dose using a questionnaire can be achieved if essential information, foremost the treatment types conducted and the radiation shielding devices used by the physicians, is registered.