2006 AAO Annual Meeting. Ocular radiation hazard of medical practitioners involving radiation exposure. Andrew K . C . L AM 1 , PhD, FAAO; Karl KL FUNG 2 , MSc, PhD; Suk-tak CHAN 2 , PhD.
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2006 AAO Annual Meeting
Ocular radiation hazard of medical practitioners involving radiation exposure
Andrew K.C. LAM1, PhD, FAAO; Karl KL FUNG2, MSc, PhD; Suk-tak CHAN2, PhD
1School of Optometry, 2Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong SAR, China.
Radiotherapy is a common treatment modality for malignant neoplasms.1 Coronary angiography, coronary angioplasty and stenting are major interventions conducted by cardiologists.2-3 Modern neuroimaging techniques, both diagnostic and therapeutic, also involve radiation hazard.4Interventionists appeared to have higher risk in cataract development.5This study aimed at evaluating the ocular status of different practitioners (including cardiologists, radiologists, and radiographers) involving radiation exposure.
Based on the registry of relevant governing boards, over 1500 letters were sent to the above mentioned practitioners for gathering information such as number of years of service, type and frequency of radiation being exposed, and types of protective measures. Respondents were invited for comprehensive eye examination with particular attention being drawn to the assessment of crystalline lens transmission and dry eye. Crystalline lens transmission was measured using an Anterior Eye Segment analysis system, EAS-1000 (Nidek Co., Ltd., Aichi, Japan). Conventional tests for dry eye syndrome were carried out, including McMonnies dry eye questionnaire, Schirmer test without topic anesthesia, Phenol red test, and fluorescein tears break-up time.6-7
This is the first study evaluating ocular radiation hazard of practitioners with frequent radiation exposure. Their risk of cataract and dry eye syndrome are not particular high as suggested by Haskal.5 There are recommendations for patients to have fewer radiation exposures undergoing invasive procedures.9 Radiologists, on the other hand, may not even know the difference on radiation dose between one computed tomography scan and one chest X-ray.10 Practitioners under regular radiation exposures should therefore maintain a record of radiation exposures.11 Although we did not find any significant radiation-related ocular problems among these practitioners, the use of lead goggles should be encouraged.
Almost all practitioners wore lead apron but just 46%of the radiologists wore lead goggles during fluoroscopic and interventional radiology procedures. There were 59% of the cardiologists wore lead goggles for the same procedures (Figure 2). Radiographers rarely wore lead goggles.
No practitioners had lens transmission below 90% on either eye, with an average lens transmission of 98%, evaluated using the EAS-1000 system. Five subjects, age ranged from 47 to 54 years, had grade 1 cataract (either nuclear or cortical type) identified with the World Health Organization grading system.8
Fifty-one subjects had at least two positive dry eye signs bilaterally. If subjective symptoms were also considered for the diagnosis of dry eye syndrome (McMonnies dry eye score > 14), only 4 radiographers were diagnosed with dry eye syndrome.
Figure 1. The percentage of time involved in radiation-related work.
This study is funded by the Occupational Safety and Health Council (HK).
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11 Eason CF. Medical exposures of radiation workers – Should they be recorded? J Occupational Medicine 1974;16:189191.
Figure 2. The use of radiation protective devices by different practitioners.
There were 363 replies received and 199 practitioners went through the eye examination. Over 70% of the respondents had post-qualified working experience within 20 years. Most of them spent 30% of their time
doing radiation related work (Figure 1). The two most commonly performed procedures for radiographers were intravenous urography and fluoroscopic examinations, and ultrasound and fluoroscopic examinations for radiologists.