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Friday, March 11, 2011

Radiation damage to the eye


Everyday we receive small amounts of radiation exposure due to the naturally occurring radiation in the environment. The average person in the U.S. receives about 3mSv per year from radioactive materials in the environment. http://www.livestrong.com/ In comparison, a CT scan will give the body a dose of 10mSv.
X-rays although invisible to the naked eye, are extremely powerful, and can be dangerous and harmful just as they can be beneficial. Any exposure to radiation has the ability to destroy tissue, damage organs and permanently alter cells.
As a rule, the benefit of a diagnostic radiologic procedure outweigh the risk by the radiation. x-rays are beneficial for the doctor to accurately diagnose and treat the disease. Radiographers have the education to be certain that the patient receive as low a dose of radiation as possible and still produce the best image (ALARA). They are also educated to protect themselves and the patient from radiation exposure that is unnecessary.
Although the Radiologist and Radiographer are educated, it is the responsibility of the patient to weigh the risks and benefits of the test before undergoing any diagnostic procedure.
Different structures of the body are more radiosensitive than others.
Most sensitive: Blood forming organs, reproductive organs, and digestive organs
Least sensitive: nervous system, muscle and connective tissue
Although the eye has a relatively high threshold for radiation damage, no amount of radiation can be considered completely safe. Doses that are capable of producing skin burns are capable of producing significant and permanent damage to the eye. Studies have shown that doses greater than 200 rad (2gray) are capable of producing cataracts in the lens of the eye. (http://www.nature.com/eye/journal ) (This link also explores the microscopic study of the x-ray irradiated rabbit cornea.)
Different parts of the eye are more radiosensitive than others: " The posterior interocular zone include the retina, choroid and optic disc. They are relatively resistant to doses up to 50 Gy, at which point retinal swelling that is usually temporary can occur. Most damage is chronic in nature, with the mechanism of damage relating more to damage of th blood vessels in the eye. Radiation damage to the vessels can occlude or obliterate them, resulting in eschemia to the posterior interocular components. Retinal damage can result in vision loss, and formation of new vessels and exudates can be seen. The optic nerve can also suffer from lack of blood flow which can lead to visual impairment, which can sometimes improve over several months. Usually six months to three years is the time frame it takes for these types of damage and changes to manifest. The lens has potential for radiation damage as it has regularly dividing cells around its equator, which are very susceptible to radiation damage. Cataracts can develop within two to three years." http://www.livestrong.com/
It is important that individuals are aware of the risk associated with radiation and take necessary precautions. Available for purchase are optically clear lead glassware that can reduce exposure by 85 - 90%. Glasses can be purchased with a wrap around design to protect the eye lens from side angle exposure.

4 comments:

  1. I am so going to wear goggles in fluoroscopy. I would like to keep my eyesight :D

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  2. Why don't we see more protective eyewear out there?? Nice pictures!

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  3. I'm definitely getting some googles.

    I always have this fear I'm going to be totally blind by the time I'm 30. :P

    Nice blog Julene!

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  4. The pictures of the eyeballs is cool..and a little scary! My eye sight isn't that great so protecting the eyes is going to be very important!

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