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Radiation Protection (Time, Distance and Shielding)

Radiation Protection basics come down to time, distance and shielding. In x-ray radiography and interventional imaging, including fluoroscopy there are three sources of radiation within the room. 1) Primary field that is used during imaging. This is the highest radiation level as this is the x-ray flux that is used to produce the images. 2) Scatter with the X-ray tube itself 3) Scatter from the x-rays passing through the patient and table. The largest contribution of dose in the room outside of the primary beam is x-ray scatter. To reduce the radiation dose that the staff in the room receive including the radiologic technologists it is important to keep in mind the primary methods of radiation protection time, distance and shielding. Time: There is a direct relationship between the time that the x-rays are on and the dose received by staff in the room. Therefore reducing the time that the direct beam is on will directly reduce the radiation dose to staff in the room. Distance: The radiation dose decreases like 1/R^2, i.e. one over R squared, where R is the distance from the source of radiation. Therefore, if you can move back twice as far from the source of the radiation, i.e. the patient, then your radiation dose can be reduced to one quarter (1/4) of the dose. Shielding: Additional materials can be placed in between you and the radiation source to shield you by reducing the radiation exposure to the parts of the body which are covered by the shielding. Lead aprons can be very effective in reducing the radiation dose. Additional movable barriers can also be used and may contain windows as well wherein the window is acting to shield the radiation as well. Lead is a particularly good shielding material as it is a high Z material so is effective at absorbing the radiation via the photoelectric effect.