- What Is an X-ray?
- The X-ray Procedure
- Before an X-ray
- After an X-ray
- X-ray Risks
- What Happens During an X-ray?
- Does COPD show up on an X-ray?
- Having an X-ray
- Radiation Health Effects
- Acute Radiation Syndrome from Large Exposures
- Radiation Exposure and Cancer Risk
- Exposure Pathways
- Sensitive Populations
- Do x-rays and gamma rays cause any other health problems?
What Is an X-ray?
This longstanding form of medical imaging is still one of the most useful.
An X-ray is a procedure that produces images of the inside of your body.
X-ray beams are a form of electromagnetic radiation, first discovered by German professor Wilhelm Conrad Roentgen in 1895.
In the procedure, a machine sends X-ray beams through your body.
The resulting images are recorded either on film or by a computer.
X-ray images show the body in shades of black and white, because different tissues absorb different amounts of radiation.
Dense materials in the body (such as bones or metal) show up as white on an X-ray image.
Parts of the body that contain air appear as black, while muscle, fat, and fluids show up as shades of gray.
Sometimes, a contrast medium (containing iodine or barium) is injected, swallowed, or delivered as an enema to provide more detail on X-ray images.
X-rays can examine many parts of the body. Some of the most common reasons X-rays are given are to view or diagnose:
- Bone fractures or infections
- Tooth decay
- Bone cancer
- Lung infections such as pneumonia
- Breast cancer
- Blocked blood vessels
- Swallowed objects
- Digestive tract problems
- An enlarged heart
The X-ray Procedure
X-rays can be performed at a doctor’s office, dentist’s office, hospital, or other medical facility.
The procedure can take anywhere from a few minutes to more than an hour, depending on the type of image your doctor or dentist needs.
A technician will position your body and the X-ray machine.
You will need to remain still and may have to hold your breath during the X-ray. Movement can cause blurry images.
The machine will capture images of your body as you sit, stand, or lie still. The process is painless.
If you need a contrast medium for your X-ray, you’ll swallow it or receive it by an intravenous injection or enema ahead of time.
Before an X-ray
Follow all instructions your doctor provides before an X-ray.
Be sure to let your doctor know if you’re pregnant or may become pregnant.
Also, tell your doctor if you’re using an intrauterine device (IUD) for birth control.
You may have to remove all jewelry and other metal objects from your body before having an X-ray.
After an X-ray
Typically, you can resume normal activities after an X-ray.
Be sure to drink plenty of fluids if you had an X-ray with a contrast medium.
X-rays expose your body to radiation, which some people worry could raise the risk of developing cancer.
However, the level of exposure in adults is usually very low, and the benefits typically outweigh the risks.
Let your doctor know if you’re pregnant, because radiation exposure may not be safe for an unborn baby.
If you receive a contrast medium for your X-ray, you could experience the following side effects:
- Metallic taste
- Lightheadedness or nausea
- Hives or itching
- Flushing of face and neck
In rare cases, the contrast medium can cause a serious reaction, such as:
- Severe low blood pressure
- Cardiac arrest
- Anaphylactic shock (a severe allergic reaction)
What Happens During an X-ray?
Most X-rays don’t require any special preparation. The doctor may ask you to take off jewelry, eyeglasses, or any metal objects or clothing that could get in the way of the image.
Doctors can take images while you stand up or lie down. It depends on the area of your body being examined. The X-ray tube hangs over the table. The film is in a drawer under the table.
The machine sends a beam of radiation through your body. Your hard, dense bones block that beam, so they show up as white on the film below you. The radiation also goes through softer tissue like muscle and fat, which appear in shades of gray in the X-ray. The air in your lungs will look black in the image.
You won’t feel anything during an X-ray, but it can be hard to hold still, and the exam table might be uncomfortable. The technician may take images from a few different angles. She might use pillows or sandbags to prop up a body part to get a better view of the area. She’ll probably ask you to hold your breath so the image doesn’t blur.
Sometimes, the doctor needs more contrast on the image to clearly see what’s going on. She might give you a contrast agent, like barium or iodine. You’ll either swallow it or get is as a shot.
The machine makes clicks and buzzing sounds during the X-ray. The process could take just a few minutes for a bone X-ray or more than an hour for more complicated issues.
X-ray images are digital, so a doctor can see them on a screen within minutes in an emergency. For nonemergencies, it may take a day or so for the doctor to review the X-ray and get back to you with the results.
Does COPD show up on an X-ray?
There are visual indicators that may appear on an X-ray of someone with COPD.
Someone who is checking on the progression of their condition may be familiar with what their symptoms look like on an X-ray, but they may be surprising to someone who has only just had a diagnosis of COPD.
Share on PinterestHyperinflation of the lungs can cause shortness of breath.
Chest X-rays of people with COPD may show signs of large lungs, known as hyperinflation.
Hyperinflation occurs when the lung tissue has been damaged and loses its elasticity. The lungs may also be trapping the air after each breath.
The result of this is that the person cannot make use of as much air with each breath as they otherwise would, which often leads to symptoms that include shortness of breath or difficulty breathing.
X-rays may also reveal structural changes in the lungs or surrounding tissue. The diaphragm may appear flattened in the chest, for example. This is also a result of hyperinflation, as the larger lungs push against the diaphragm, forcing it downward.
Changes in airways
Changes in the airways of the lungs are an early sign of COPD.
These changes can be difficult to accurately diagnose, as a study of the different imaging techniques posted to the Journal of Thoracic Disease notes.
Doctors take any potential changes they see in the airways as a sign to investigate further.
Doctors may also identify bullae on the X-ray.
Bullae are pockets of air that may develop when emphysema damages lung tissue. These pockets of air grow and can take away usable space in the lungs, which can make correct lung function difficult.
Doctors will usually plan to surgically remove bullae because they can be dangerous if left untreated.
The heart may change shape as COPD progresses. An X-ray in people with emphysema may reveal a narrow or elongated-looking heart muscle.
This may be partly because of the heart changing how it sits in the chest to make room for the expanding lungs.
It may also happen because there is less volume in the left ventricle of the heart.
Having an X-ray
During an X-ray, you’ll usually be asked to lie on a table or stand against a flat surface so that the part of your body being examined can be positioned in the right place.
The X-ray machine, which looks like a tube containing a large light bulb, will be carefully aimed at the part of the body being examined by the radiographer. They will operate the machine from behind a screen or from the next room.
The X-ray will last for a fraction of a second. You won’t feel anything while it’s carried out.
While the X-ray is being taken, you’ll need to keep still so the image produced isn’t blurred. More than one X-ray may be taken from different angles to provide as much information as possible
The procedure will usually only take a few minutes.
In some cases, a substance called a contrast agent may be given before an X-ray is carried out. This can help show soft tissues more clearly on the X-ray.
Types of X-rays involving a contrast agent include:
- barium swallow – a substance called barium is swallowed to help highlight the upper digestive system
- barium enema – barium is passed into your bowel through your bottom
- angiography – iodine is injected into a blood vessel to highlight the heart and blood vessels
- intravenous urogram (IVU) – iodine is injected into a blood vessel to highlight the kidneys and bladder
These types of X-rays may need special preparation beforehand and will usually take longer to carry out. Your appointment letter will mention anything you need to do to prepare.
Radiation Health Effects
Ionizing radiationIonizing radiationRadiation with so much energy it can knock electrons out of atoms. Ionizing radiation can affect the atoms in living things, so it poses a health risk by damaging tissue and DNA in genes. has sufficient energy to affect the atoms in living cells and thereby damage their genetic material (DNA). Fortunately, the cells in our bodies are extremely efficient at repairing this damage. However, if the damage is not repaired correctly, a cell may die or eventually become cancerous. Related information in Spanish (Información relacionada en español).
Exposure to very high levels of radiation, such as being close to an atomic blast, can cause acute health effects such as skin burns and acute radiation syndrome (“radiation sickness”). It can also result in long-term health effects such as cancer and cardiovascular disease. Exposure to low levels of radiation encountered in the environment does not cause immediate health effects, but is a minor contributor to our overall cancer risk.
Visit the U.S. Centers for Disease Control and Prevention (CDC) for more information about possible health effects of radiation exposure and contamination.
On this page:
- Acute radiation syndrome from large exposures
- Radiation exposure and cancer risk
- Limiting cancer risk from radiation in the environment
- Exposure pathways
- Sensitive populations
Acute Radiation Syndrome from Large Exposures
A very high level of radiation exposure delivered over a short period of time can cause symptoms such as nausea and vomiting within hours and can sometimes result in death over the following days or weeks. This is known as acute radiation syndrome, commonly known as “radiation sickness.”
It takes a very high radiation exposure to cause acute radiation syndrome—more than 0.75 graygrayA gray is the international unit used to measure absorbed dose (the amount of radiation absorbed by an object or person). The U.S. unit for absorbed dose is the rad. One gray is equal to 100 rads. (75 rad)radThe U.S. unit used to measure absorbed radiation dose (the amount of radiation absorbed by an object or person). The international equivalent is the Gray (Gy). One hundred rads are equal to 1 Gray. in a short time span (minutes to hours). This level of radiation would be like getting the radiation from 18,000 chest x-rays distributed over your entire body in this short period. Acute radiation syndrome is rare, and comes from extreme events like a nuclear explosion or accidental handling or rupture of a highly radioactive source.
View CDC Fact Sheet: Acute Radiation Syndrome (ARS).
Learn about protecting yourself from radiation.
Learn about radiation sources and doses.
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Radiation Exposure and Cancer Risk
Exposure to low-levels of radiation does not cause immediate health effects, but can cause a small increase in the riskriskThe probability of injury, disease or death from exposure to a hazard. Radiation risk may refer to all excess cancers caused by radiation exposure (incidence risk) or only excess fatal cancers (mortality risk). Risk may be expressed as a percent, a fraction, or a decimal value. For example, a 1% excess risk of cancer incidence is the same as a 1 in a hundred (1/100) risk or a risk of 0.01. of cancer over a lifetime. There are studies that keep track of groups of people who have been exposed to radiation, including atomic bomb survivors and radiation industry workers. These studies show that radiation exposure increases the chance of getting cancer, and the risk increases as the dose increases: the higher the dose, the greater the risk. Conversely, cancer risk from radiation exposure declines as the dose falls: the lower the dose, the lower the risk.
Radiation doses are commonly expressed in millisievertssievertAn international unit used to measure effective dose. The U.S. unit is rem. (international units) or remremThe U.S. unit to measure effective dose. The international unit is sieverts (Sv). (U.S. units)sievertAn international unit used to measure effective dose. The U.S. unit is rem.. A dose can be determined from a one-time radiation exposure, or from accumulated exposures over time. About 99 percent of individuals would not get cancer as a result of a one-time uniform whole-body exposure of 100 millisieverts (10 rem) or lower.1 At this dose, it would be extremely difficult to identify an excess in cancers caused by radiation when about 40 percent of men and women in the U.S. will be diagnosed with cancer at some point during their lifetime.
Risks that are low for an individual could still result in unacceptable numbers of additional cancers in a large population over time. For example, in a population of one million people, an average one-percent increase in lifetime cancer risk for individuals could result in 10,000 additional cancers. The EPA sets regulatory limits and recommends emergency response guidelines well below 100 millisieverts (10 rem) to protect the U.S. population, including sensitive groups such as children, from increased cancer risks from accumulated radiation dose over a lifetime.
Calculate your radiation dose.
Learn about radiation sources and doses.
Learn more about cancer risk in the U.S. at the National Cancer Institute.
Learn more about how EPA estimates cancer risk in, EPA Radiogenic Cancer Risk Models and Projections for the U.S. Population, also known as the Blue Book.
Limiting Cancer Risk from Radiation in the Environment
EPA bases its regulatory limits and nonregulatory guidelines for public exposure to low level ionizing radiation on the linear no-threshold (LNT) model. The LNT model assumes that the risk of cancer due to a low-dose exposure is proportional to dose, with no threshold. In other words, cutting the dose in half cuts the risk in half.
The use of the LNT model for radiation protection purposes has been repeatedly recommended by authoritative scientific advisory bodies, including the National Academy of Sciences and the National Council on Radiation Protection and Measurements Exit. There is evidence to support LNT from laboratory data and from studies of cancer in people exposed to radiation. 2,3,4,5
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Understanding the type of radiation received, the way a person is exposed (external vs. internal), and for how long a person is exposed are all important in estimating health effects.
The risk from exposure to a particular radionuclideradionuclide Radioactive forms of elements are called radionuclides. Radium-226, Cesium-137, and Strontium-90 are examples of radionuclides. depends on:
- The energy of the radiation it emits.
- The type of radiation (alpha, beta, gamma, x-rays).
- Its activity (how often it emits radiation).
- Whether exposure is external or internal:
- External exposure is when the radioactive source is outside of your body. X-rays and gamma rays can pass through your body, depositing energy as they go.
- Internal exposure is when radioactive material gets inside the body by eating, drinking, breathing or injection (from certain medical procedures). Radionuclides may pose a serious health threat if significant quantities are inhaled or ingested.
- The rate at which the body metabolizes and eliminates the radionuclide following ingestion or inhalation.
- Where the radionuclide concentrates in the body and how long it stays there.
Learn more about alpha particles, beta particles, gamma rays and x-rays.
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Children and fetuses are especially sensitive to radiation exposure. The cells in children and fetuses divide rapidly, providing more opportunity for radiation to disrupt the process and cause cell damage. EPA considers differences in sensitivity due to age and sex when revising radiation protection standards.
1 National Research Council, 2006. Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR VII Phase 2. Washington, DC: The National Academies Press (p. 7).
2 Brenner, David J. et al., 2003 “Cancer risks attributable to low doses of ionizing radiation: assessing what we really know.” Proceedings of the National Academy of Sciences 100, no. 24, (pp. 13761-13766).
3 National Council on Radiation Protection and Measurements, 2018. Implications of Recent Epidemiologic Studies for the Linear Nonthreshold Model and Radiation Protection, NCRP Commentary 27. Bethesda, Maryland: National Council on Radiation Protection and Measurements.
4 Shore, R.E. et al., 2018. “Implications of recent epidemiologic studies for the linear nonthreshold model and radiation protection.” Journal of Radiological Protection, no 38,(pp. 1217-1233)
5 U.S. Environmental Protection Agency, 2011. “EPA Radiogenic Cancer Risk Models and Projections for the U.S. Population.” EPA Report 402-R-11-001.
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The editors of the New England Journal of Medicine presented the eleven most important medical developments of the past thousand years in the first issue of the year 2000 (1). Internal imaging of the human body was selected as one of those developments. Since Wilhelm Conrad Roentgen discovered x-rays in 1895, medical applications of x-rays have been accepted worldwide as essential tools for protecting and improving human health. On the other hand, they also represent by far the largest human-made source of radiation exposure.
X-ray is one of ionizing radiations that carry enough energy to free electrons from molecules. When biologic tissue is exposed to ionizing radiations, hydroxyl radicals can be created from their interaction with water molecules; these radicals in turn interact with nearby DNA to cause strand breaks. It can lead to induction of mutations which are linked to carcinogenesis (2). People are exposed to radiation on a daily basis from various sources, such as natural radioactive materials in water, food and stones, cosmic rays, nuclear power generation and x-ray diagnosis or treatment. Radiation dose limit for individual members of the public is 1 mSv per year, i.e. one-hundredth of the maximum limit for radiation workers. On the contrary, the guiding principle is: the dose should be as low as reasonably achievable. This is called the “ALARA Principle” and is central to all radiation safety.
X-rays have been used in the medical field for almost 130 years, but the introduction of computed tomography (CT) in the 1970s was revolutionary. The use of CT has increased rapidly and it now became one the most popular examinations owing to recent technical advancements, such as multi-detector CT and hybrid imaging. According to the OECD Health Data 2015, Korea had a large number of CT scans hitting 37.7 per million, which is the sixth-largest among the OECD members. It is estimated that more than one in Koreans underwent CT scans in each year and they are increasing 20% per year since 2005. CT emits a powerful dose of radiation, in some cases equivalent to hundreds of plain radiographs, resulting in a marked increase in radiation exposure in the population. Radiation exposure by CT scan per person was more than half of total radiation exposure by diagnostic x-ray.
It is very difficult to calculate how many cancers will result from medical imaging. Even though no large-scale epidemiologic studies of the cancer risks associated with CT scans have been reported; a commonly quoted estimate for excess cancer mortality from radiation exposure is 1 death per 2,000 scans. It was estimated that 1.5%-2% of all cancers in the United States may be attributable to the radiation from CT studies (2).
According to recommendations of International Commission on Radiological Protection (ICRP), radiation protection (RP) is based on three fundamental principles: justification, optimization and dose limitation (3). The principle of justification requires that any decision that alters the radiation exposure situation should do more good than harm. The principle of optimization requires that the likelihood of incurring exposures, the number of people exposed and the magnitude of their individual exposure should all be kept as low as reasonably achievable, taking into account economic and societal factors. The third principle of dose limitation requires that the dose to individuals from planned exposure situations, other than medical exposure of patients, should not exceed the appropriate limits recommended by the Commission.
RP represents a substantial part of the quality management system in our clinical practice. It could be achieved in several ways, including decreasing the number of unnecessary procedures as well as the dose per procedure. Rigorous effort should be paid to build-up evidence-based guidelines that offer guidance as to when imaging study of ionizing radiation is indicated. Healthcare providers should fully understand the fundamental principles of RP, and have to inform patients of risks before imaging. The industry, the standardization organizations as well as many professional medical societies are also dedicating significant effort to radiation safety aspects in medicine. The best outcome will only be accomplished when all the actors manage to work together.
Do x-rays and gamma rays cause any other health problems?
X-rays and gamma rays can cause a number of other problems besides cancer. What problems occur depend upon the radiation dose, the timing of the exposure, and what areas of the body are exposed.
Exposure to high doses of radiation over a short period of time can cause radiation sickness (sometimes called radiation poisoning or acute radiation syndrome) and even death. Some of the symptoms of radiation sickness include fainting, confusion, nausea and vomiting, diarrhea, hair loss, skin and mouth sores, and bleeding. The atomic bomb blasts in Hiroshima and Nagasaki led to many cases of radiation sickness. Since then, some cases have resulted from nuclear power plant accidents, such as those in Chernobyl and in Fukushima.
Doses of radiation such as those given in radiation therapy also cause side effects. Short-term side effects depend on the area being treated but often include skin changes (ranging from mild reddening to something like a severe burn), nausea, vomiting, diarrhea, and low blood cell counts. There is also a risk of long-term side effects, which again vary depending on the area being treated. For example, radiation to the head and neck area can lead to problems with dry mouth and trouble swallowing. Radiation can weaken bones, so that they are more likely to break later on. Radiation to the bone marrow can lead to long-term problems with blood cell counts and even a disease called aplastic anemia. Radiation can also lead to infertility (problems getting pregnant or fathering children)
Lower doses of radiation, such as from imaging tests are not known to cause short-term health problems.