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Radiation Exposure From Ct Scan

What Can I Do If Im Worried About Radiation From Imaging Tests

Radiation Dose with CT Scan-Mayo Clinic

If you have concerns about the radiation you may get from a CT scan, PET scan, or any other imaging test that uses radiation, talk to your health care provider. Ask whether the test is needed and if its the best one to use in your case. You may also want to know what you and your health care provider can expect to learn from it.

The best advice at this time is to get only the imaging tests that are needed and try to limit your exposure to all forms of radiation. If you do need to have a test that will expose you to some radiation, ask if there are ways to shield the parts of your body that arent being imaged. For example, a lead apron can be used to protect parts of your chest or abdomen from getting radiation, and a lead collar can be used to protect your thyroid gland.

You may also want to keep a medical imaging record to track your own history of imaging tests and share it with your health care providers. This may help prevent repeat tests from being ordered. English and Spanish examples of imaging records for adults can be found online at www.imagewisely.org.

Remember that MRI and ultrasound exams do not expose you to radiation.

What Are The Risks Of Ct Scans For Children

Radiation exposure from CT scans affects adults and children differently. Children are considerably more sensitive to radiation than adults because of their growing bodies and the rapid pace at which the cells in their bodies divide. In addition, children have a longer life expectancy than adults, providing a larger window of opportunity for radiation-related cancers to develop .

Individuals who have had multiple CT scans before the age of 15 were found to have an increased risk of developing leukemia, brain tumors , and other cancers in the decade following their first scan. However, the lifetime risk of cancer from a single CT scan was smallabout one case of cancer for every 10,000 scans performed on children.

In talking with health care providers, three key questions that the parents can ask are: why is the test needed? Will the results change the treatment decisions? Is there an alternative test that doesnt involve radiation? If the test is clinically justified, then the parents can be reassured that the benefits will outweigh the small long-term risks.

Ct Procedures And Radiation Exposure

Whenever you get an x-ray, CT, or other nuclear imaging procedures, you are exposed to ionizing radiation. These energy wavelengths penetrate tissue and produce images to reveal the state of your internal organs. Ionizing radiation can damage DNA, but your cells are usually able to repair most of that damage. Radiation exposure is measured in units called millisieverts.

Humans are exposed to small doses of radiation every day, mainly from the sun, at an average of 3 millisieverts per year. Overall, radiation exposure in the United States population has doubled due to the increasing use of medical imaging. Today, CT scans alone account for 24% of all ionizing radiation exposure in the country.

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Ct Scanning And Radiation Safety

Studies show that the risk of cancer from CT scans is extremely low.

Sometimes, your health condition will require an imaging exam that uses ionizing radiation. If you have concerns, talk to your doctor about the need for and importance of the exam. Your radiologist also can explain the exams importance as well as any risk.

CT is a proven, lifesaving imaging technology. It allows the physician to see inside the body. For the past 15 to 20 years, CT has helped guide treatment in ways we previously never thought possible. More importantly, it helps the physician determine if no treatment is necessary.

A CT scan should never be withheld from a child or adult who has a medical condition where the scan could provide important healthcare information. It may save the patient’s life.

The question you should ask is: “What should be done regarding my healthcare and diagnostic imaging tests?” Patients need to make sure their medical condition is assessed and managed each and every time in accordance with proper medical care.

Questions to ask:

  • How will this imaging exam affect my treatment?
  • For a cancer patient undergoing chemotherapy guided by CT, the answer is clear. For patients with benign diseases, the answer may be less obvious.
  • Remember: A CT scan provides valuable information to your physician and can be a great relief to you.
  • Is there an alternative imaging method available that does not use radiation?
  • Do not be afraid to have this dialog with your physician.
  • Ionizing Radiation And Cancer Risk

    The CT Scanner

    We’ve long known that children and teens who receive high doses of radiation to treat lymphoma or other cancers are more likely to develop additional cancers later in life. But we have no clinical trials to guide our thinking about cancer risk from medical radiation in healthy adults. Most of what we know about the risks of ionizing radiation comes from long-term studies of people who survived the 1945 atomic bomb blasts at Hiroshima and Nagasaki. These studies show a slightly but significantly increased risk of cancer in those exposed to the blasts, including a group of 25,000 Hiroshima survivors who received less than 50 mSv of radiation an amount you might get from three or more CT scans.

    The atomic blast isn’t a perfect model for exposure to medical radiation, because the bomb released its radiation all at once, while the doses from medical imaging are smaller and spread over time. Still, most experts believe that can be almost as harmful as getting an equivalent dose all at once.

    Imaging procedures and their approximate effective radiation doses*

    Procedure

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    Who Should Not Have Imaging Tests Done

    Some people are more susceptible to complications from radiation exposure, and we take extra care to manage that risk. Though the risk of getting cancer from the radiation from imaging scans is extremely low, its a little higher for women and younger patients. Younger patients who have chronic medical problems may need repeated imaging throughout their lifetimes, so we are extra cautious with them. We try to minimize the number of CT scans we give those patients and instead opt for MRIs or ultrasounds when possible.

    Kids growing bodies are especially susceptible to radiation, so our pediatric radiologists minimize radiation exposure to pediatric patients whenever possible. Similarly, pregnant women should not undergo CT scans and X-rays unless they are absolutely necessary. Its important to remember that different imaging tests are better to look at different parts of the body, so depending on a patients medical issues, an MRI or ultrasound may not be the best test.

    For any test, its always important to look at the risks and the benefits. In most cases, the benefit of finding cancer or confirming the need for surgery outweighs the risk from radiation exposure from a CT scan.

    If youre concerned about radiation exposure during an imaging test, or if you have questions about any of the tests recommended to you, dont hesitate to ask your doctor or technologist. We want you to be comfortable, and its your right to know how the tests work and why theyre important.

    Increasing Ct Usage And Radiation Exposure

    In their review, Drs. Brenner and Hall1 describe the marked increased in the use of CT scanning, from three million scans in the U.S. in 1980, to 20 million in 1995, to over 60 million in 2005. Although the risk for an individual is small, in a few decades up to 2% of all cancers may be due to radiation exposure from CT scans, an increase from the current estimated rate of 0.4%. In addition, CT use is projected to increase even more in the future due to screening of asymptomatic patients, such as chest CT for lung cancer in smokers, virtual colonoscopy and cardiac/coronary artery scans. However, before any screening program is instituted, its benefit over the risks of radiation must clearly be established.

    The radiation dose and risk of malignancy vary substantially with age of the patient from one in 10,000 for patients over age 40 years, to roughly one in 500 for a neonate.1,12 Infants have a more than ten-fold greater risk than middle-aged adults due to their increased radiation sensitivity, smaller size, and longer life span, which provides a greater length of time for induction of malignancy. However, this calculation presumes that the same CT radiation settings are used in children as in adults. One major method to reduce radiation exposure in children is to reduce the radiation settings of the scanner based on the size of the patient. The earlier work of Dr. Brenner was instrumental in bringing attention to this issue.1214

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    Exposure To Ionizing Radiation On The Rise

    The radiation you get from x-ray, CT, and nuclear imaging is ionizing radiation high-energy wavelengths or particles that penetrate tissue to reveal the body’s internal organs and structures. Ionizing radiation can damage DNA, and although your cells repair most of the damage, they sometimes do the job imperfectly, leaving small areas of “misrepair.” The result is DNA mutations that may contribute to cancer years down the road.

    We’re exposed to small doses of ionizing radiation from natural sources all the time in particular, cosmic radiation, mainly from the sun, and radon, a radioactive gas that comes from the natural breakdown of uranium in soil, rock, water, and building materials. How much of this so-called background radiation you are exposed to depends on many factors, including altitude and home ventilation. But the average is 3 millisieverts per year.

    Exposure to ionizing radiation from natural or background sources hasn’t changed since about 1980, but Americans’ total per capita radiation exposure has nearly doubled, and experts believe the main reason is increased use of medical imaging. The proportion of total radiation exposure that comes from medical sources has grown from 15% in the early 1980s to 50% today. CT alone accounts for 24% of all radiation exposure in the United States, according to a report issued in March 2009 by the National Council on Radiation Protection and Measurements.

    Radiation Dose From Ct Examinations

    Researchers Working To Reduce Radiation Exposure During CT Scan

    The quantity most relevant for assessing the risk of cancer detriment from a CT procedure is the “effective dose”. The unit of measurement for effective dose is millisieverts . Effective dose allows for comparison of the risk estimates associated with partial or whole-body radiation exposures. It also incorporates the different radiation sensitivities of the various organs in the body.

    Radiation dose from CT procedures varies from patient to patient. The particular radiation dose will depend on the size of the body part examined, the type of procedure, and the type of CT equipment and its operation. Typical values cited for radiation dose should be considered as estimates that cannot be precisely associated with any individual patient, examination, or type of CT system. The actual dose from a procedure could be two or three times larger or smaller than the estimates. Facilities performing “screening” procedures may adjust the radiation dose used to levels less than those typically used for diagnostic CT procedures. However, no comprehensive data is available to permit estimation of the extent of this practice and reducing the dose can have an adverse impact on the image quality produced. Such reduced image quality may be acceptable in certain imaging applications.

    Table 1 – Radiation Dose Comparisons

    Diagnostic Procedure
    Coronary CT angiogram 16

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    Radiation Risk From Medical Imaging

    There’s always questions about radiation exposure from medical imaging. Patients want to know if radiation from mammograms, bone density tests, computed tomography scans, and so forth will increase their risk of developing cancer. For most women, there’s very little risk from routine x-ray imaging such as mammography or dental x-rays. But many experts are concerned about an explosion in the use of higher radiationdose tests, such as CT and nuclear imaging.

    Over 80 million CT scans are performed in the United States each year, compared with just three million in 1980. There are good reasons for this trend. CT scanning and nuclear imaging have revolutionized diagnosis and treatment, almost eliminating the need for once-common exploratory surgeries and many other invasive and potentially risky procedures. The benefits of these tests, when they’re appropriate, far outweigh any radiation-associated cancer risks, and the risk from a single CT scan or nuclear imaging test is quite small. But are we courting future public health problems?

    What About Patients Who Need Multiple Ct Scans

    People who have cancer often need CT scans every few months to determine if their treatment is working. Some patients worry that repeated CT scans will give them cancer again in the future. I try to reassure these patients that while there is theoretically a small risk of getting a new cancer in many years from radiation exposure, the risk of having a complication from their existing cancer is much larger.

    We dont want to frighten anyone, so its important to maintain some perspective. Most people dont realize this, but we are exposed to some radiation every day. All Americans have small amounts of radon in our homes, which gives us small doses of background radiation. We get radiation every time we take a cross-country flight. People who live at higher altitudes, such as Denver, Colorado, are exposed to more radiation than people who live at lower altitudes, such as Dallas-Fort Worth. While no one should be exposed to medical radiation unnecessarily, if a patient needs a CT scan, the risk of radiation exposure should not hold him or her back from getting it.

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    What Are Ct Scan Radiation Side Effects

    Is CT scan radiation danger over-exaggerated? Or do these medical procedures represent real risks to patient and medical personnel health?

    As already stated, the vast majority of patients have nothing to fear from the occasional CT scan. The threshold for concern is 100 mSv, which could take dozens of scans to hit, and the threshold for specific radiation-induced conditions, like the depression of the blood cell-forming process or cataracts is much higher.

    Instead of radiation, CT scan side effects are almost entirely caused by the contrasting liquid you drink prior to procedures like chest and abdomen scans. These rare side effects include:

    • Abdominal cramping

    If you develop any of these rare side effects or have trouble breathing after consuming the contrasting liquid, go to the emergency room immediately.

    How To Understand And Communicate Radiation Risk

    Ct Scan Chest Radiation Exposure

    Donald J. Peck, PhD, Henry Ford Health System, Detroit, MIEhsan Samei, PhD, Duke University Medical Center, Durham, NCUpdated March 2017 |

    Many medical imaging examinations involve exposure to ionizing radiation. The exposure amount in these exams is very small, to the extent that the health risk associated with such low levels of exposure is frequently debated in scientific meetings. Nonetheless, the prevailing scientific view is that there is a finite amount of risk involved with such exposures. The risk is increased with the amount of exposure, repeated exposures, and when the patient is young. This material aims to provide a brief overview of the risk associated with medical imaging examinations that involve ionizing radiation.

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    What Is Total Or Whole

    Total, or whole-body, CT creates pictures of nearly every area of the bodyfrom the chin to below the hips. This procedure, which is used routinely in patients who already have cancer, can also be used in people who do not have any symptoms of disease. However, whole-body CT has not been shown to be an effective screening method for healthy people. Most abnormal findings from this procedure do not indicate a serious health problem, but the tests that must be done to follow up and rule out a problem can be expensive, inconvenient, and uncomfortable, and they may expose the patient to extra risks, such as from an invasive procedure like a biopsy that may be needed to evaluate the findings. In addition, whole-body CT can expose people to relatively large amounts of ionizing radiationabout 12 mSv, or four times the estimated average annual dose received from natural sources of radiation. Most doctors recommend against whole-body CT for people without any signs or symptoms of disease.

    Here Are Average Radiation Doses For Common Medical Imaging Procedures:

    Chest x-ray 0.02 mSv

    Spinal and pelvic CT 6 mSv

    Chest CT 7 mSv

    Angiogram CT 16 mSv

    Nuclear imaging is a relatively new medical technology, so there is little data available regarding exact risk estimates for radiation exposure experienced during CT procedures. For any one person, the risk of radiation-induced cancer is much smaller than the natural risk of cancer .

    Radiation specialists recognize the need to minimize radiation exposure during CT procedures. New strategies are being adopted to reduce patient dose while maintaining high-quality images for diagnostic purposes.

    Here are five simple steps being implemented in medical facilities worldwide:

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    New Ct Scan Method Lowers Radiation Exposure

    23 July 2020

    A CT scan technique that splits a full X-ray beam into thin beamlets can deliver the same quality of image at a much reduced radiation dose, according to a new UCL study.

    The technique, demonstrated on a small sample in a micro CT scanner, could potentially be adapted for medical scanners and used to reduce the amount of radiation millions of people are exposed to each year.

    A computerised tomography scan is a form of X-ray that creates very accurate cross-sectional views of the inside of the body. It is used to guide treatments and diagnose cancers and other diseases.

    Past studies have suggested CT scans may cause a small increase in lifelong cancer risk because their high-energy wavelengths can damage DNA. Although cells repair this damage, sometimes these repairs are imperfect, leading to DNA mutations in later years.

    In the new study, published in Physical Review Applied, researchers placed a mask with tiny slits over an X-ray beam, breaking up the beam into beamlets. They then moved the sample being imaged in a cycloidal motion that ensured the whole object was irradiated quickly that is, no parts of it were missed.

    The researchers compared the new technique to conventional CT scanning methods, where a sample rotates as a full beam is directed on to it, finding it delivered the same quality of image at a vastly reduced dose.

    The study was funded by the Royal Academy of Engineering and UK Research and Innovation .

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