Health Risks of X-Rays
X-rays can detect life-threatening conditions such as broken bones and some types of cancer. They also guide medical personnel as they insert tubes or other devices into the body.
For routine X-rays, there are no side effects, but you may need to remove metal objects such as jewellery and hairpins before the test. Some X-rays use contrast medium, which can cause a reaction in some people, including a rash and feeling sick.
The amount of radiation you absorb during an x-ray depends on the size and position of the organ being imaged. Your sensitivity to the radiation can also vary, but in general, the low dose of radiation used in diagnostic imaging is not enough to cause long-term damage.
In fact, everyone is exposed to a small amount of radiation naturally every day. It comes from radon and cosmic rays, which are found in the air, water, soil, and rocks. Radiation is even released when you fly in a plane or drive a car, though the risk is very small.
The radiation dose is measured in millisieverts (mSv), with reference to the human body as a whole. An effective dose is calculated for each organ, adjusted to account for the sensitivity of the organ to radiation. Radiation risks increase as the effective dose increases, but the risk is still very low. The benefits of diagnostic x-rays outweigh the potential risks.
Contrast medium, or contrast agents, are liquid or semi-solid substances used to highlight certain parts of the body in medical imaging exams (such as X-ray, CT, MRI and ultrasound). They can be made up of different compounds. Some are injected into blood vessels or arteries, while others are swallowed or administered through the digestive system.
The radiologist carrying out your test or procedure will decide if contrast is needed and which type of contrast agent is best. They will take into account information from your doctor or specialist, and the area of the body being scanned.
Some contrast materials, like iodinated contrast, can temporarily make your kidney function worse (20-40% of patients). This is called contrast-induced nephropathy (CIN). It is caused by a reduction in medullary blood flow and direct tubular damage. Fortunately, the risk of this is very low. Most contrast media passes through the body naturally in about 24 to 48 hours. You may find that your stool is light-colored after the procedure.
Many women are concerned about having medical procedures while pregnant that may pose risks to their fetuses. Extremely high doses of radiation can have severe effects on a developing fetus, including microcephaly (small head), a small jaw, microphthalmia (small eyes) and genital and skeletal malformations. Luckily, the dose of radiation used in medical x-rays is far less than this level.
However, if the x-ray is directed at your stomach or abdomen, your fetus could come into direct contact with the x-ray beam. It is unknown if this could cause harm, so most doctors avoid taking x-rays in pregnant women. In the event that an x-ray or test that uses x-rays is absolutely necessary, doctors may use imaging studies that do not involve radiation such as ultrasound or magnetic resonance imaging (MRI). These types of imaging tests are considered safe for pregnancy and do not expose your fetus to any unnecessary risks. However, this is not always possible or practical.
While x-rays produce radiation that can cause damage to living tissue, doctors use the lowest dose possible to obtain the images needed to diagnose medical problems. In addition, the benefits of x-rays far outweigh any potential risks.
Using a technique called effective dose, doctors estimate the risk of cancer for each imaging procedure by comparing it to the amount of radiation an individual receives naturally in a day. The risk increases with the length of the exam and the number of x-ray exams done over an extended period of time.
Some types of x-rays require you to swallow a liquid called contrast medium, which helps outline a specific area of the body on the image. Contrast mediums are typically made of barium and iodine, and may cause temporary side effects such as a rash or vomiting.
Some x-rays are used to guide medical personnel as they insert tubes, stents or other devices in the body. These procedures are likely to cause more significant radiation exposure than a routine diagnostic exam, but they have not been reported to cause long-term biological effects such as skin reddening or infertility.