X-Rays

What are x-rays and what do they do?

X-rays are a form of radiant energy, like light or radio waves. Unlike light, x-rays can penetrate the body, which allows a radiologist to produce pictures of internal structures. The radiologist can view these on photographic film or on a TV or computer monitor.

X-ray examinations provide valuable information about your health and play an important role in helping your doctor make an accurate diagnosis. In some cases x-rays are used to assist with the placement of tubes or other devices in the body or with other therapeutic procedures.

Measuring radiation dosage

The scientific unit of measurement for radiation dose, commonly referred to as effective dose, is the millisie Pregnancy and x-rays

Most standard x-ray examinations of the abdomen are not likely to pose a serious risk to the child. Some abdominal and pelvic studies such as CT deliver greater amounts of radiation to a developing pregnancy. Informing the radiologist that you are or might be pregnant is important so that your medical care can be planned with both you and your baby in mind. Remember, this is done to optimize medical care by reducing any potential risk.

Radionuclide exams, also known as nuclear medicine, also use x-ray-like radiation. But the method of use is quite different from x-rays and they produce very different looking images. The same advice for informing your physician or the nuclear medicine technologist about any possible pregnancy before the examination begins is important.

However, in nuclear medicine another precaution is advised for women who are breast-feeding a child. Some of the pharmaceuticals that are used for the study can pass into the mother's milk and subsequently the child will consume them. To avoid this possibility, it is important that a nursing mother inform her physician and the nuclear medicine technologist about this before the examination begins. Usually, you will be asked to discontinue breast-feeding for a short while, pump your breasts in the interim and discard the milk. Breast-feeding can often resume shortly afterwards.

vert (mSv). Other radiation dose measurement units include rad, rem, roentgen, and sievert.

Because different tissues and organs have varying sensitivity to radiation exposure, the actual dose to different parts of the body from an x-ray procedure varies. The term effective dose is used when referring to the dose averaged over the entire body.

The effective dose accounts for the relative sensitivities of the different tissues exposed. More importantly, it allows for quantification of risk and comparison to more familiar sources of exposure that range from natural background radiation to radiographic medical procedures.

X-ray safety

As with other medical procedures, x-rays are safe when used with care. Radiologists and x-ray technologists have been trained to use the minimum amount of radiation necessary to obtain the needed results. The amount of radiation used in most examinations is very small and the benefits greatly outweigh the risk of harm.

X-rays are produced only when a switch is momentarily turned on. As with visible light, no radiation remains after the switch is turned off.

Pregnancy and x-rays

As with any aspect of medical care, knowing that a patient is or could be pregnant is important information. Pregnancy, for example, might explain certain symptoms or medical findings. When a pregnant patient is ill or injured, the physician will carefully select medications to avoid potential risks to the developing child. This is also true of x-rays.

While the vast majority of medical x-rays do not pose a critical risk to a developing child, there may be a small likelihood of causing a serious illness or other complication. The actual risk depends on how far along the pregnancy is and on the type of x-ray. Ultrasound studies, for example, don't use x-rays and have never demonstrated any potential for risk to a pregnancy. X-ray studies of the head, arms, legs and chest do not usually expose the baby directly to x-rays and typically the technologist who takes the x-rays will implement special precautions to ensure that the baby of a pregnant patient is not directly exposed.

Source "U.S. Food and Drug Administration"