X-rays are highly energetic electromagnetic radiation that are well outside the range of visual perception. Because of their high energy, they are capable of forming ions by knocking
electrons off atoms. For this reason, they are classified as ionizing radiation. This ionizing of atoms can break down the molecules of living tissue and cause adverse health effects. Extreme x-ray exposure causes the symptoms of radiation sickness such as hair loss, bleeding, gastrointestinal problems, and skin sores. Medium to long-term effects such as cancer, low blood cell counts, and infertility is possible.
Much has been learned about the health effects of x-ray radiation since its discovery in 1895. As a result, threshold x-ray exposure limits were established, beneath which, no known short-term health problems will occur. By consistently limiting exposures below this threshold, healthcare personnel, technicians, and researchers can avoid short-term health effects.However, the long-term effects of low exposure levels can still cause health problems. One of these, the formation of cataracts in the lens of the eye, comes about from cumulative x-ray exposure. Studies suggest there is no safe low-dose threshold to ionizing radiation for preventing cataracts. There is an inverse relationship between when cataract formation occurs and x-ray dosage level. Low dosage levels merely delay its onset when exposure is frequent.
X-Ray Scatter and Cataracts
When primary radiation from an x-ray machine hits the patient, some of the x-rays are deflected. X-rays may also be deflected by objects such as the table or chair that the patient is on. This scattered radiation can affect nearby doctors and/or technicians. The intensity of this scatter depends on a number of variables such as distance away from the patient and angular positioning relative to the patient.X-ray scatter is generally most intense on the entrance side of the patient and least on the exit side. Large patients tend to produce more scatter than small patients. The amount of scatter that reaches the eyes of a doctor or technician will also depend on their height.Two safety measures followed by many doctors and technicians are to stand a minimum distance away from the patient and to wear badge monitors on their person. Provided these two measures are always followed and the badge monitors indicate no exposure, it’s assumed that the adverse health effects of x-ray scatter are negligible.
However, this doesn’t mean one’s exposure to scatter is zero. In fact, it has been demonstrated that x-ray scatters beyond this safe distance has sufficient intensity to pass through a person’s hand and produce an x-ray image of the bones within the hand. This occurred even though the technician’s badge monitor showed no exposure. The reason for this is that the film that imaged the bones had greater sensitivity to x-rays than the badge.The significance of this is that even when standing a “safe” distance away from the patient and when one’s badge monitor indicates no exposure, small doses of stray radiation still penetrate the unprotected eye. Technicians following standard safety measures such as these through countless x-ray tests may come to believe that radiation safety glasses are redundant.However, as mentioned previously, cataract formation occurs from cumulative exposure to x-rays of any intensity. People with long careers spanning several decades that involve multiple x-ray exposures during each workday can total tens of thousands of exposures. In terms of cataract risk, this is significant. The fact that much of the population develop cataracts in late life because of other risk factors, means that this accumulated x-ray exposure increases one’s risk relative to the general population.
Professionals exposed to long-term/low-intensity x-rays include:
- Radiological technologists
- Interventional radiologists and cardiologists
- Fluoroscopy radiologists
- Laboratory scientists, researchers, and technicians
Of the healthcare professionals that use x-ray equipment, interventional radiologists and cardiologists are at greatest risk. Using x-ray imaging in real-time subjects these professionals to lengthy exposure times. In addition, performing these procedures requires being in close proximity to the x-ray target (the patient), which increases the exposure level to scatter radiation. The risk of eye cataract development from cumulative low-level radiation exposure over the course of a career is particularly high. This risk is also high for fluoroscopy radiologists.Laboratory scientists, researchers, and technicians who use analytical x-ray equipment are also at risk to low-level x-ray exposure. They are subject to leakage radiation from the x-ray tube housing and to scatter radiation.
Cataracts occur when the lens of the eye becomes opaque or clouded. The risk factors for the general population include:
- Increasing age
- High blood pressure
- Excessive alcohol consumption
- Excessive ultraviolet exposure from the sun
For the professionals discussed previously, cumulative low-level x-ray exposure is yet another risk factor. Many of the above risk factors can be eliminated. However, eliminating x-ray exposure is easiest of all because you need only wear radiation safety glasses when using x-ray equipment.Although your vision may be fine right now, the damaging effects of long-term x-ray exposure on the lenses of your eyes are progressive, and it may be just a matter of time before your vision is affected. Remember that the professions exposed to x-rays are a minority. This places you at a higher risk than the rest of the general population, and their long-term risk is sizeable.To ensure that wearing radiation safety glasses becomes a habit, it helps to wear glasses that you are comfortable using. Fortunately, the variety of shapes, colors and sizes of these glasses is quite extensive. In addition, corrective eye prescription safety glasses are also available. For more information about our radiation safety glasses and answers to your questions, contact us.