Although high doses of ionizing radiation can be harmful to human health, radiation and radioactive materials are used every day in medical settings to improve health outcomes and even save lives.

About Imaging Procedures

Radiation is used in many medical imaging procedures. Medical imaging procedures deliver x-ray beams, a form of ionizing radiation, to a specific part of the body creating a digital image or film that shows the structures inside that area like bones, tissues, and organs. Healthcare providers can use these images for diagnostics, finding out what is causing your health problem, or sometimes to guide treatment. Imaging procedures are usually performed in radiology or imaging centers in hospitals or clinics by a radiologist, a medical professional who is trained and certified to conduct imaging studies with radiation. Medical radiation practices and equipment are regulated by state and federal programs to ensure safety.

Benefits and Risks

There are possible short-term and long-term risks from the very low doses of radiation exposure from imaging procedures. Ionizing radiation can damage cell DNA, but in the low amounts used in each imaging procedure cells can normally repair themselves. When cells get too much radiation over time, this damage can lead to cancer.

Although we all are exposed to ionizing radiation every day, any added exposures, including from imaging procedures, slightly increases the risk of developing cancer later in life.

Usually, the benefits of diagnosing or treating health problems with ionizing radiation will outweigh these risks. These procedures only deliver radiation to the area that needs imaging, protecting all other parts of the body, and should always use the lowest amount of radiation needed to create a good quality image (referred to as “as low as reasonably achievable” – ALARA).

Talk to your healthcare provider and radiologist about the specific benefits and risks of the procedure recommended for your specific situation. These are some of the general benefits and risks for imaging that uses radiation:

Benefits

• Gives healthcare providers a better view of organs, blood vessels, tissues, and bones.
• Provides detailed information to help decide whether surgery is a good treatment option.
• Can be used to guide medical procedures to place catheters, stents, or other devices inside the body (fluoroscopy, a type of imaging).

Risks

• Each procedure contributes to a slight increase in the likelihood that you could develop cancer later in life.
• Fluoroscopy for guiding surgery uses higher doses of radiation than other imaging procedures and may cause skin reddening and hair loss.
• Some imaging procedures require you to drink or receive an intravenous (IV) contrast dye. This non-radioactive dye helps the radiologist see specific organs or parts of the body. Some people can have an allergic reaction to the dye.

How to Limit Your Exposure

The best way to make sure you are not getting more exposure to radiation than necessary from imaging studies is to keep track of imaging procedures and make sure each healthcare provider or specialist you see receives your results. This includes sending previous imaging results to any new healthcare provider before your visit.

It is important to tell your healthcare provider and the radiologist if you are pregnant or think you could be pregnant.

To help reduce your exposure and to help decide what type of imaging or testing is best for you, consider asking your health care provider:

• Do any of my recent tests provide the imaging needed?
• Are there other tests that do not use radiation that can provide the needed information?

For your procedure, the radiologist will use the lowest amount of radiation needed and these doses are further reduced for children. During the procedure you will often receive a lead protective shield to prevent other areas of your body that don’t need imaging from being exposed to radiation.

Other medical radiation experts include the following:

• Hospital radiation safety officer
• Medical physicist
• Radiation physicist
• Diagnostic medical physicist

Imaging Procedures That Don’t Use Radiation

Some alternative imaging procedures that do not use ionizing radiation include Magnetic Resonance Imaging (MRI) and ultrasound.

MRI procedures use magnetic fields and radio waves to produce images of specific parts of the body. Ultrasound imaging uses high-frequency sound waves to see inside the body.

You and your healthcare provider will select the best type of imaging procedure for your situation and make sure the potential benefits to your health outweigh possible risks from the procedure.

Radiation can be dangerous, but it can also save lives. How can that be? Harnessed properly, radiation can help diagnose and even treat disease. So when you’re faced with a medical test that uses radiation, don’t let fear get in your way. Learn about the risks and benefits, and know what questions to ask. If medical radiation is really needed, take steps to ensure that it’s done as safely as possible.

Radiation, simply put, is the transfer of energy through space. The energy may be in the form of invisible particles or waves. Radiation is all around us—and has been throughout our evolution—so our bodies are designed to deal with the low levels we’re exposed to every day. Excess radiation, however, can damage tissues and lead to serious problems.

Why is radiation used in medicine? “Radiation allows radiologists and other physicians to see internal parts of the body that they aren’t able to see directly with their eyes or through other physical examination measures,” explains Dr. Steven Krosnick, a radiologist at NIH.

Techniques like x-rays and CT scans send controlled amounts of radiation through the body and create images based on what comes through the other side. Another imaging method called nuclear medicine uses compounds that emit radiation, which can then be detected outside the body. Injected or swallowed, these compounds can target a specific area and reveal internal problems. Or they can be used to track how well internal organs are working.

With these advanced imaging tools, doctors can detect disease early, when it’s easier to treat. As a result, use of medical radiation has been rising. But with these benefits come some risks.

“One of the main risks of being exposed to radiation is the possibility of developing a cancer,” says Krosnick. Cancer takes years to develop, so it’s nearly impossible to tell exactly what causes any given cancer. As a result, it’s hard for researchers to gauge exactly how much risk a given amount of radiation poses.

Children’s growing bodies are even more susceptible to radiation damage than those of adults. Children have a long lifetime ahead. Any damage caused by radiation has a longer period of time to show itself.

Earlier this year, a worrisome report linked childhood CT scans to 2 types of cancer later in life: leukemia and brain cancer. The NIH-funded study looked at more than 175,000 children and young adults. Depending on the radiation dose, those who’d received 2 or more scans had a small boost in cancer risk. Because these cancers are rare, the benefits of CT scans likely outweigh the risks, the researchers concluded. Still, they suggest that doctors consider alternatives to CT scans or use the lowest possible radiation doses.

Strangely enough, radiation can also be used to treat cancer. Focused doses of high-energy radiation can kill cancer cells and shrink tumors. Medical imaging tests, in contrast, use much lower doses.

“The fundamental thing to understand is that these procedures all deliver a generally low amount of dose,” says Dr. George Sgouros at the Johns Hopkins University School of Medicine. “In some cases, depending on your disease, it’s potentially riskier to not get the scan or nuclear medicine procedure than to get it.”

Sgouros and his colleagues have been investigating how to strike a balance between radiation risk and the benefit of having clear images for diagnosis. “If you’re so concerned about the radiation risk that you give too little, you could misdiagnose the patient,” he says.

Traditionally, the amount of radiation used in an imaging test was based on weight. Sgouros’s team used computer simulations to examine the effects of different doses in a nuclear medicine scan. “We found that we could give roughly half as much of the radioactivity to a tall, thin child than to a short, stout child and get the same quality image,” he says.

His group is now planning to do similar analyses for a variety of different body shapes and sizes. Eventually, the researchers hope to create guidelines that take into account not only weight but also height, sex, age and other factors. Similar efforts are under way to optimize CT scans and X-rays.

Dr. Rebecca Smith-Bindman of the University of California, San Francisco, has been studying the trends. She thinks we’re turning to radiation-based tests too often. This summer, her group published a report showing a sharp rise in the use of these tests between 1996 and 2010. “It’s not just the sick and the intensive care patients getting these exams,” she says. “Everyone’s getting them, across a whole spectrum of disease, both serious and trivial, and therefore any potential harm really needs to be considered.”

If a doctor recommends a test that uses radiation, ask about its risks and benefits. If the test is truly needed, do some research into the imaging facilities. Find one that monitors the doses they’re giving patients and takes pride in low doses. “We have found that there’s enormous variation in dose for the same clinical test,” Smith-Bindman says. Doses can vary not only between facilities, she explains, but at the same facility based on the time of day and who’s conducting the test.

If you’re faced with the prospect of an imaging test, fight fear with knowledge. Check out our “Wise Choices” box for some questions to ask your doctor.

Ask About Your Imaging Test

If you’re considering an imaging test, here are some questions to ask:

• What are we hoping to learn from the test?
• How is it going to help me?
• Will the test results change how my disease is managed?
• Do I need the test now, or can I wait?
• Is there another test I can use instead? If so, what are the benefits and risks of each?
• How can I be sure the test will be done in the safest way possible?
• Can you make sure to use the lowest radiation dose for what you need to know?
• For children: Is the facility using pediatric protocols for the test?

Computed tomography, or CT, scans are medical imaging tests that use ionizing radiation to create cross-sectional (slices) pictures inside selected areas of the body from different angles. The images can show internal organs, blood vessels, soft tissues, and bones. CT scans combine a series of x-ray (radiography) images into a three-dimensional picture.

What You Should Know

Your healthcare provider may ask for a CT scan to detect, diagnose, or plan treatment for a particular disease or injury.

Common uses of CT scan include checking for:

• Tumors
• Infections
• Blood clots
• Internal bleeding

We all are exposed to ionizing radiation every day from the natural environment but added exposures can increase the possibility of developing cancer later in life. Your healthcare provider will recommend a CT scan when the benefits to your health outweigh the risk.

Talk to your healthcare provider and radiologist (medical professional that performs tests using radiation) if you have any questions or concerns to decide on the best options for you.

What To Expect

Before the procedure

The radiologist will explain the procedure and ask you if you have any questions. Some CT procedures may use a contrast dye which allows healthcare providers to see specific organ(s). You may be asked to drink the contrast dye or you may receive it in an intravenous (IV) line in the hand or arm.

Make sure to tell your healthcare provider and the radiologist doing the test if you:

• Have ever had an allergic reaction to any contrast dye.
• Are pregnant or suspect that you may be pregnant.

During the Procedure

• You will be asked to remove any clothing and jewelry that may interfere with the procedure.
• You will be asked to lie very still on a table while it moves slowly through an x-ray machine (like a tube) taking images of your body.
• The computer will organize the x-ray information to show the internal structures in detail.

Additional Benefits and Possible Health Effects of CT Scans

CT scans usually require more exposure to radiation than common x-rays because they use a series of x-ray images. Increased exposure means a slightly higher risk of possible short-term and long-term health effects. However, CT scans provide your healthcare provider with more detailed images that can include parts of the body that may not be seen on common x-ray images. Talk to your healthcare provider to decide what type of imaging will use the least amount of radiation while providing the information and details needed for your diagnosis.

Nuclear medicine uses radioactive material inside the body to see how organs or tissue are functioning (for diagnosis) or to target and destroy damaged or diseased organs or tissue (for treatment).

Nuclear medicine vs common imaging procedures using x-rays: how they work

Although we all are exposed to ionizing radiation every day from the natural environment, added exposures like those from nuclear medicine procedures can slightly increase the risk of developing cancer later in life.

Talk to your healthcare provider to decide on the best procedure for your health needs and discuss any concerns you have.

What You Should Know

Your healthcare provider may recommend a nuclear medicine procedure to diagnose or treat a health problem.

When It’s Used for Diagnosis

Nuclear medicine can show how the organs or tissues are functioning. For most diagnostic procedures, a tracer, which contains the radioactive material, is injected, swallowed, or inhaled. Then the healthcare provider or radiologist (a healthcare professional with special training to use radiation in healthcare) uses a radiation detector to see how much of the tracer is absorbed or how it reacts in the organ or tissue. This will give the provider information about how well it is functioning.

Common uses of nuclear medicine for diagnosis include:

• Scans of the heart, lung, kidneys, gallbladder, and thyroid

In a type of nuclear medicine called positron emission tomography (PET), the tracer is used to show the natural activity of cells, providing more detailed information on how organs are working and if there is damage to the cells. PET scans are often combined with computed tomography (CT) scans or magnetic resonance imaging (MRI) which provide three-dimensional images of the organ.

Common uses of PET scans include:

• Diagnosing heart disease, Alzheimer’s disease, and brain disorders
• Getting detailed information about cancerous tumors to decide the best treatment option

When it’s used for treatment

When used in treatment, the tracer targets a harmful organ or tissue and radioactivity damages or stops the growth of its cells.

Two common uses of nuclear medicine for treatment include radioactive iodine therapy and brachytherapy (a form of radiation treatment where a sealed radiation source is placed inside or next to the area requiring treatment).

What To Expect

Before the procedure

• You will receive a tracer either through an injection, inhalation (breathing it in), or through a pill or substance to swallow.
• You may need to wait a certain amount of time for the tracer to travel through your body to the tissue or organ being diagnosed or treated.

During the procedure

• You may be asked to lie down on a table or to walk on a treadmill.
• A camera that detects radiation will be placed over your body to collect information on how the tracer is acting in an organ or tissue.

After the procedure

• The radiologist and your healthcare provider use this information to see how an organ or tissue is functioning.
• The radioactive material from the tracer will pass out of your body in a few hours to a few days, depending on the type of tracer and test you receive.

When You Go Home

Right after your procedure, your body is very slightly radioactive (giving off radiation) but this wears off with time and is not directly harmful to others. Your healthcare provider may give you special instructions to help reduce any small amounts of radiation you give off from exposing others such as washing your hands frequently. Drinking a lot of water may help the radioactive material leave your body quicker.

• Before you leave, ask your healthcare provider if there are steps you should take to protect others or if you have any concerns or questions about information you were given.
• Talk to your healthcare provider if you are currently breastfeeding.

The ionizing radiation dose for these procedures is typically higher than the dose received from a common x-ray procedure. There are always some possible risks from exposure to ionizing radiation in healthcare, but these procedures should be used when the health benefits outweigh these risks.

Benefits and Risks of Nuclear Medicine

Benefits

• Provides information on how organs, tissues, and cells are working. (Other common imaging procedures only show the structures.)
• Can be used also in targeted treatments to kill or damage harmful or cancerous cells, reduce the size of tumors, or reduce pain.

Risks

• Radiation doses are usually higher than in common imaging like x-rays. This means these procedures are slightly more likely to increase the possibility you may get cancer later in life.
• Some nuclear medicine procedures are longer and use more radiation than others. These could cause skin reddening and hair loss.
• You may give off small amounts of radiation right after your procedure and need to take steps to protect others from exposure.

DEXA (dual x-ray absorptiometry) scans measure bone density (thickness and strength of bones) by passing a high and low energy x-ray beam (a form of ionizing radiation) through the body, usually in the hip and the spine. This procedure is important for diagnosing (seeing if someone has) osteoporosis or bone thinning and may be repeated over time to track changes in bone density.

The amount of radiation used in DEXA scans is very low and similar to the amount of radiation used in common x-rays. Although we all are exposed to ionizing radiation every day from the natural environment, added exposures can slightly increase the risk of developing cancer later in life.

What You Should Know

Your healthcare provider may recommend a DEXA scan to test for osteoporosis or thinning of your bones.

Screening for osteoporosis is recommended for women who are 65 years old or older and for women who are 50 to 64 and have certain risk factors, such as having a parent who has broken a hip. However, there are other risk factors for osteoporosis besides age and gender, such as some intestinal disorders, multiple sclerosis, or low body weight. Your healthcare provider may recommend a DEXA scan if you have any of these other risk factors. DEXA scans should be used when the health benefits outweigh the risks. Talk to your healthcare provider about any concerns you have before a DEXA scan.

• Nearly 1 in 5 women and 1 in 20 men over the age of 50 are affected by osteoporosis.
• Osteoporosis increases the risk for broken bones and can have serious effects in older adults.

What To Expect

Before the procedure

• Make sure to let your healthcare provider or radiologist (medical professional specially trained in radiation procedures) if you are pregnant or think you may or could be pregnant.
• Dress in loose, comfortable clothing. Don’t wear anything that has metal on it like buckles, buttons, or zippers. Metal can interfere with test results.

During the procedure

• You may be asked to remove jewelry, eyeglasses, and any clothing that may interfere with the imaging.
• You will lay on a table and the radiologist or medical assistant will position your legs on a padded box. They also may place your foot in a device so that your hip is turned inward.
• While the image is taken, lay still and follow instructions. You may need to hold your breath for a few seconds.

After the procedure

• The procedure typically lasts about 15-20 minutes.
• Your healthcare provider will follow up with you with your results. They will show a T-score and a Z-score. The T-score shows how your bone density compares to the optimal peak bone density for your gender. The Z-score shows how your bone density compares to the bone densities of others who are the same age, gender, and ethnicity.

Benefits and Risks of DEXA Scans

DEXA scans are different from other imaging procedures because they are used to screen for a specific condition.

Benefits:

• Detects weak or brittle bones to help predict the odds of a future fracture
• Determines if bone density is improving, worsening, or staying the same
• Can help you and your healthcare provider come up with plans to improve your bone strength and prevent worsening conditions

Risks:

• A very slight increase in possibility of future cancer, similar to the risks from x-rays.

Fluoroscopy is a medical procedure that makes a real-time video of the movements inside a part of the body by passing x-rays through the body over a period of time. X-rays are a form of ionizing radiation. Fluoroscopy can be used for diagnosing (finding out the cause of) a health problem such as heart or intestinal disease. It also can be used to guide treatments such as implants or injections, or in orthopedic surgery. It helps the healthcare provider look inside organs, joints, muscles, and bones.

Although we all are exposed to ionizing radiation every day from the natural environment, added exposures like those from fluoroscopy procedures can slightly increase the risk of developing cancer later in life.

What You Should Know

Your healthcare provider may recommend a fluoroscopy procedure to diagnose disease or guide treatment procedures for a particular health concern.

Fluoroscopy is commonly used to:

• Check how the stomach and intestines are working.
• Check if food is being properly swallowed and how the muscles of the mouth and throat are working.
• Guide medical procedures to place catheters, stents, or other devices inside the body, such as in the heart or blood vessels.
• Guide injections (shots) deep into the spine or joints.
• See broken bones and whether surgery has fixed them in proper position to heal.

Coronary angiography is an example of a fluoroscopy procedure. A small tube (catheter) is inserted into an artery of the heart. Contrast dye moves through the catheter into the blood vessels. The fluoroscopy shows how the blood moves through the vessels and allows the healthcare provider to locate any blockages.

Your healthcare provider will recommend fluoroscopy when the benefits to your health outweigh the risk.
Talk to your healthcare provider if you have any questions or concerns or to decide on the best options for you.

What To Expect

Before the procedure

Some fluoroscopy procedures may use a contrast dye which allows medical provider to see specific organ(s). You will be asked to either drink the dye or you will receive it in an intravenous (IV) line in your hand or arm.

Make sure to let your healthcare provider or radiologist (medical professional specially trained in radiation procedures) know if:

• You have ever had a reaction to any contrast dye.
• If you have kidney disease or poor kidney function.
• You are pregnant or think you could be pregnant.

You may be asked to take a pregnancy test before the procedure.

During the procedure

• You will be asked to remove any clothing and jewelry that may interfere with the procedure.
• You will be positioned on the procedure table and, depending on the type of procedure, you may be asked to get in different positions, move a specific body part, or hold your breath at intervals while the fluoroscopy is being performed.
• Anesthesia or sedation may be used depending on the procedure.

Benefits and Risks of Fluoroscopy Procedures

Benefits:

• Allows healthcare providers to see movement and function (like in a movie) that cannot be seen in other fixed imaging studies (like a photograph).
• Guides sometimes life-saving surgical treatments.

Risks:

• Radiation doses are usually higher than in common imaging like x-rays. This means these procedures are slightly more likely to increase the possibility you may get cancer later in life.
• Some fluoroscopy procedures are longer and use more radiation than others. These could cause skin reddening and hair loss.
• Contrast dye, if used, can produce an allergic reaction in some people.

While fluoroscopy itself is not painful, the procedure being performed may be painful, such as the injection into a joint or accessing of an artery or vein for angiography.

The radiologist will take all comfort measures possible, which could include local anesthesia, conscious sedation, or general anesthesia, depending on the procedure.

Mammograms for breast cancer screening can help find breast cancer early—before there are any signs or symptoms. A mammogram, or mammography exam, uses x-ray beams (a form of ionizing radiation) to create images of the inside of the breast. Healthcare providers use mammograms to check for breast cancer and other conditions that may cause symptoms in the breast of both men and women.

Finding and treating cancer early can greatly improve the chances of full recovery and may mean shorter and less invasive treatments. Some risks from mammograms include false results and exposure to a small dose of ionizing radiation during the procedure. We all are exposed to ionizing radiation every day from the natural environment, but additional exposures can lead to an increase in the possibility of developing cancer later in life.

What You Should Know

Your healthcare provider may recommend a mammogram for breast cancer screening or for other symptoms in the breast like a lump, pain, changes in breast skin texture (such as turning red, dimpled, or puckered), or nipple discharge.

The United States Preventive Services Task Force recommends:

• Mammograms every two years for women who are 50-74 years old and are at average risk for breast cancer.
• Women who are 40-49 years old should talk to their healthcare provider about when or how often to get a mammogram based on personal risk and health history.

Work with your healthcare provider to decide on the best screening process and schedule for you. Your healthcare provider may recommend a mammogram when they believe that benefits outweigh the risks for your health.

What To Expect

Before The Procedure

• Make sure to let your healthcare provider or radiologist (medical professional specially trained in radiation procedures) know if you are pregnant or think you could be pregnant.
• Do not wear deodorant, talcum powder, or lotion under your arms or on your breast area on the day of the exam.
• The radiologist will tell you what clothing or other items you are wearing (such as jewelry or eyeglasses) to remove so they can get clear images.

During The Procedure

• Your breast will be placed on a special platform and compressed with a clear plastic paddle. You may experience discomfort.
• You will be asked to change positions between images. The routine views are a top-to-bottom view and an angled side view. The process will be repeated for the other breast.
• You must hold very still and may be asked to hold your breath for a few seconds while the x-ray picture is taken to reduce the possibility of a blurred image.
• The information collected will be processed to show the structures in the breast and any abnormalities.

Risks & Benefits

Benefits

Mammograms

• Are specifically designed to look for breast diseases and can find cancers up to three years before they can be felt. Early detection helps successful treatment.
• Can track changes in breast tissue over time.
• Help guide treatment when cancer is present.

Risks

• Results can sometimes be false.
  • A false-positive test, one that indicates you may have cancer when you truly do not, may lead to extra expenses, testing, and stress.
  • A false-negative test, one that says you do not have any cancer when you truly do, may delay your diagnosis and treatment.

You likely have had x-rays before. X-rays, formally referred to as radiographs, are common imaging procedures ordered by healthcare providers and dentists. X-ray machines pass x-ray beams (a form of ionizing radiation) through a part of the body to produce images of the tissue, organs, bones, or teeth inside. These images allow healthcare providers and dentists to see if there are problems, like a broken bone or a cavity.

We are all exposed to ionizing radiation every day from the natural environment without any immediate health impacts. Added exposures, from procedures such as medical imaging, can lead to an increase in our cancer risk later in life. X-rays, however, usually use the least amount of radiation compared with other imaging tests.

What You Should Know

Healthcare providers and dentists both use x-rays for your care. A healthcare provider may recommend x-rays to look for bone fractures, some types of tumors, injuries or abnormal masses, and signs of pneumonia in the lungs.

Dentists take x-rays to check for cavities or other dental problems. X-rays are also often a routine part of your dental check-up, even if you don’t think you have any dental problems or pain, so your dentist can catch any early signs of problems. How often you need x-rays at the dentist depends on your dental health history, risks or symptoms, and your age. Children typically need x-rays more often because their teeth and jaws are still developing.

What To Expect

Before the x-ray

• Make sure to let your healthcare provider or radiologist (medical professional specially trained in radiation procedures) know if you are pregnant or think you could be pregnant.
• You may be asked to remove anything metallic you are wearing like jewelry or clothing with buttons or zippers.

During the x-ray

• You may need to stand or lay down in a certain position or angle while the image is completed.
• For some dental x-rays you will be asked to bite down on a device that is placed in your mouth in a few different positions.
• Depending on the part of your body being x-rayed, you might be provided with a lead covering to prevent radiation from reaching other parts of your body.

Your healthcare provider or dentist should recommend an x-ray when they believe that the benefits to your health outweigh this small risk. Talk to your healthcare provider or dentist if you have concerns and to decide when x-rays are the best choice for you.

Medical and dental x-rays use very small amounts of radiation and only expose the smallest area of the body needed to get the image to check for a health concern. Your risk of any long-term effects of ionizing radiation from x-rays depends on the part of the body being x-rayed (some organs or tissues are more sensitive than others) and the amount of radiation exposure, which may include the total number of medical procedures using radiation, over time.

Radiation therapy is a cancer treatment that uses focused beams of radiation to shrink or kill tumors.

About Radiation Therapy

Radiation therapy uses ionizing radiation to shrink or kill tumors. Focused beams of radiation are produced by a machine outside the body and are aimed at tumor cells inside the body, damaging cells and destroying their ability to divide.

During radiation therapy radiation beams target tumors but can also damage healthy cells. Before starting therapy, doctors carefully plan where to aim the radiation beam to damage the tumor as much as possible, while doing as little damage to healthy cells as possible.

Radiation therapy does not make the patient receiving the treatment radioactive. Like shining a flashlight at your skin, your skin is illuminated where the beam hits your skin. When you turn the flashlight off, your skin returns to its normal shade and is no longer illuminated.

There are many different types of radiation therapy that can be used to treat tumors. Some examples of radiation therapy include:

• Three-dimensional Conformal Radiation Therapy (3D-CRT): 3D-CRT is a type of radiation cancer treatment that uses special computers to get an accurate picture of the size, shape and location of the tumor. 3D-CRT can use single or multiple x-ray beams to target the tumor.
• Proton therapy: Proton therapy uses a beam of protons to target tumors. Unlike x-rays, which deposit energy along their path, protons deposit the majority of their energy at the end of their path. Doctors use proton therapy to minimize damage to healthy tissue while still targeting the tumor.

Radiation therapy can cause acute side effects, such as hair loss or nausea, which can occur during treatment. Most acute effects disappear after treatment. Because radiation damages cells, it can also increase the risk of cancer. There is a small chance that the cancer treatment itself will produce another cancer years later. Radiation therapy patients are screened frequently for cancer after successful treatment of their primary tumor.

Doctors and scientists continue to research radiation therapy methods to increase accuracy, decrease damage to healthy tissue, and reduce side effects to the patient.

What You Can Do

• Follow instructions given by their doctor or radiation therapist. Make sure to let the doctor and radiation therapist know if you are pregnant, might be pregnant, or are breastfeeding.

If You Are Pregnant or May Be Pregnant

In many cases, the risk of an imaging procedure to a pregnant woman and the unborn child is very small compared to the benefit of finding out about a medical concern. However, even small risks should not be taken if they are unnecessary.

Always tell your healthcare provider and radiologist (a medical professional certified to conduct imaging studies with radiation) if you are pregnant or think you could be pregnant. If there is any chance you could be pregnant but have not confirmed it, they may ask you to take a pregnancy test. If you are pregnant your healthcare provider may decide that it would be best to cancel the medical imaging procedure, to postpone it until after you give birth, or to modify it to reduce your exposure to radiation.

What You Should Know

• Imaging done on most parts of the body, such as arms, legs, teeth, and chest, do not expose the unborn baby to radiation.
• Imaging of the midsection—such as the abdomen, stomach, pelvis, lower back, or kidneys— may expose the unborn baby to radiation.
• Doctors will assess how far along you are in your pregnancy to determine potential risks to the pregnancy.

You can discuss your options with your healthcare provider and take steps to limit your exposure to radiation.

If Your Child Needs An Imaging Procedure

Although radiation exposure from imaging is very low, children are slightly more likely to be affected by radiation than adults.

What You Should Know

Children are still growing, and their cells are quickly dividing and multiplying, so radiation can more easily interfere with cell growth and development than in adults. Cancer caused by radiation exposure takes several years to develop. Being exposed to radiation at a young age means that they have more time for radiation exposures to add up and possibly cause cancer. It is important that imaging procedures performed on children use the least amount of radiation needed.

How To Limit Exposure

You can take these steps to limit the amount of radiation your child is exposed to:

• Ask your healthcare provider or radiologist whether their facility lowers radiation doses when examining children, adjusted for size and age of the child.
• Be sure to tell your healthcare provider about previous imaging your child has had to avoid repeating or unnecessary testing.
• Ask about other imaging methods (such as ultrasound or MRI) that do not use radiation when possible.

Patients or family members of patients can take a few steps to reduce the dose of radiation during a medical imaging procedure.

• Discuss the procedure with your physician. How will an x-ray, CT scan, or fluoroscopy procedure help find out what is wrong or determine treatment? Ask if there are other acceptable alternative procedures that might give a lower radiation dose or do not use radiation, but still allow for good assessment or treatment. For example, magnetic resonance imaging (MRI) and ultrasound procedures do not use ionizing radiation.
• For conventional x-ray imaging, shielding, such as wearing a lead apron, should be used to reduce radiation exposure to other parts of the body.
• Know your medical imaging history. Keep a list of your imaging records, including dental x-rays. Discuss your diagnostic imaging history with your health care professionals to avoid unnecessary duplication of tests.