special subjects
X Rays
Disadvantages of X Rays
Other imaging tests may provide better detail, be safer or faster, or help doctors diagnose a disorder more accurately than conventional x-rays. Themain disadvantage of x-raysis Exposure to radiation For conventional x-rays, each image requires only a very small amount of radiation. For chest x-rays, the amount of radiation exposure with a single image is similar to the amount most people get from the environment in 2.4 days ( Background radiation ). However, some x-ray tests require several images, a higher dose of radiation for each image, or both. As a result, the total radiation exposure is higher, as in the following examples: For x-rays of the lower back, done in a series: The amount of radiation equals about 3 months of background exposure. For mammography, the amount equals about 1 to 2 months of background exposure. Fluoroscopy usually requires higher doses of radiation than routine x-rays, so other imaging tests are done instead when possible. Examiners take precautions to minimize a person’s exposure to radiation. Women who are or could be pregnant should tell their doctor. Then, the examiner can take all possible precautions to shield the fetus from exposure. To evaluate the abdomen or pelvis of a pregnant woman, the doctor can sometimes substitute an imaging test that does not use radiation, such as ultrasonography. However, conventional x-rays that do not involve the abdomen or pelvis usually expose the uterus to only very small amounts of radiation. Some particular types of x-rays have other Risks of Radiation in Medical Imaging . For example, barium swallowed or inserted by enema may cause constipation. 