X-rays are a type of ionizing electromagnetic radiation similar to gamma radiation. They are distinguished based on their source: X-rays are emitted by electrons, while gamma rays are emitted by the atomic nucleus.
With properly functioning instrumentation and by following the correct safety precautions, the risk of radiation exposure when working with radiation producing devices is minimal. However, it is good to know the signs of an acute exposure to a localized area of the human body.
Be aware that these effects can be caused by contact with the beam for only a fraction of a second depending on what device you are using. Typical primary beam exposures are 100,000 to 400,000 rad per minute. The most common effect of large radiation exposure from an radiation producing device is reddening of the skin (erythema). With a dose of a few hundred rem, the superficial layers of the skin are damaged, and the skin will redden in a fashion similar but more complex than a sunburn. The erythema effect will most often reverse itself within a few weeks.
It is also possible that doses at this level could damage cell division which could temporarily stop hair growth and possibly causes hair loss. Hair growth should return with lower doses.
There could also be damage to the sebaceous glands that produces the oil of the skin, which could cause a temporary decrease in the amount of oil produced.
There are other less common and less transitory responses. If a large area is exposure to a large amount of radiation, there could be changes in the skin pigmentation. This effect may not be reversible and could result in permanent skin changes.
If the exposure is large, the transitory damage to the skin, skin hair, or sebaceous glands could cause skin scarring or lead to radiation dermatitis, chronic radiation dermatitis, or radiation induced skin cancer.
Unintended X-ray radiation exposure
If you think you have experienced an unintended or inappropriate X-ray exposure, contact the Office of Radiation Safety immediately.
An incident interview will need to be conducted and an incident report will need to be generated with the Office of Radiation Safety to determine the estimated unintended exposure. Besides the description of incident, your name, date and location, type of device, and estimated exposure will all be requested during the interview. The Office of Radiation Safety will then complete a dose estimate and let you know if there are any further actions needed.
Good Safety Practices
- Each laboratory should designate a primary responsible user for the radiation producing device. This person will be responsible for the interlock bypass keys, performing the alignments, and manufacturer required maintenance on the radiation producing device(s). This person will also coordinate calibrations, repairs, and modifications of the equipment with the company or manufacturer representative, when appropriate.
Radiation Protection Practices
- Time – The shorter the time spent around an radiation producing device, the lower the radiation dose. X-ray users should minimize their exposures to keep their occupational radiation dose As Low As Reasonably Achievable (ALARA).
- Distance – Radiation levels decrease significantly with increase in distance from the source of radiation. The use of distance is one of the easiest and most effective methods for radiation protection. X-ray users should try to maintain the greatest distance from the X-ray source as possible when working with devices.
- Shielding – Lead or concrete shielding can be used to reduce radiation levels when appropriate. Most devices have built-in shielding. Some will require additional shielding placed around the device or within the room.
To protect yourself from the radiation, consider the following potential sources of radiation exposure:
- The primary beam.
- Primary beam leakage
- Beam penetration through stops and shutters
- Secondary radiations from beam interaction of the primary beam with the sample or shielding
Radiation released from the diffraction of the beam