The benefits of CT scans often outweigh the potential risks of radiation exposure. But it is important to understand the dangers involved. Every year, there are over 70 million CT scans performed in the United States, and the FDA is investigating cases of overexposure to radiation from these scans. The amount of radiation received during a CT scan can vary depending on the type of scan, body part being imaged, and patient size, and is typically higher compared to other imaging modalities such as X-rays. Effects of radiation exposure beside cancer can include reddening of the skin, loss of hair, flaky skin, cataracts, fatigue, dizziness, nausea, inability to eat, and tissue destruction.
This article contains important information about the risk of CT scans. We need to know the risks. But let’s be clear, too. The benefits of a CT scan usually outweigh the potential risks of radiation exposure, especially when it comes to diagnosing and monitoring certain medical conditions that, if not caught, will lead to further complications or exacerbation of the injury. But if a CT scan is necessary, the radiation exposure is typically kept as low as possible while still obtaining the necessary diagnostic information.
But there are legitimate practical concerns:
- Radiation Dose: The amount of radiation received during a CT scan varies depending on the type of scan, body part being imaged, and patient size. It is typically higher compared to other imaging modalities such as X-rays. Of course, a CT scan usually give you more useful information than an X-ray for most conditions. The cumulative effect of multiple scans can result in a significant increase in the radiation dose received by an individual, which can raise concern for the long-term risks associated with ionizing radiation exposure.
- Cancer Risks: Ionizing radiation from CT scans is associated with an increased risk of cancer, particularly in children and young adults. Why? Their cells are rapidly dividing and therefore more sensitive to radiation damage.
- Unnecessary scans: In some cases, CT scans may be ordered or performed more frequently than necessary, increasing a patient’s radiation exposure. This highlights the importance of careful decision-making and ensuring that CT scans are only performed when they are medically necessary. (One big thing on my radar: will you find anything on the scan that might change the currently planned treatment?)
- Vulnerable populations: Certain populations, such as pregnant women and their fetuses, are more sensitive to ionizing radiation and are therefore at increased risk of harm. The use of CT scans should be avoided in these populations whenever possible, and alternative imaging modalities should be considered.
CT Scans and Radiation
CT scans use X-rays to produce detailed images of the body, including bones, organs, and tissues. While the amount of radiation exposure from a CT scan is low, it is still considered a source of ionizing radiation, which can be harmful if the dose is too high.
The amount of radiation from a CT scan varies depending on the type of exam, the specific machine being used, and the patient’s size and anatomy. However, the radiation dose from a single CT scan is usually much lower than the amount of radiation people receive from natural sources over the course of a year.
But we are not out of the woods. Radiation exposure is still a big deal. It should be kept as low as reasonably achievable, especially for children and pregnant women, who are more sensitive to the effects of ionizing radiation. In many cases, alternative imaging tests that do not use ionizing radiation, such as MRI or ultrasound, can be used instead of a CT scan. If a CT scan is necessary, healthcare providers will consider the potential benefits and risks and only recommend the exam if it is deemed necessary. Doctors have to pay attenton to how the patient is positioned because that impacts radiation exposure.
It is fine line doctors have to walk. We had a case where a boy died of an anuryusm because they didn’t bother to do a CT scan. You can say we blame the doctors either way. I get that. But the reality doctors have a duty to do what other reasonable doctors would do.
Radiation Is Cumulative
It’s also important to keep in mind that radiation exposure is cumulative, meaning that the more radiation you are exposed to over your lifetime, the greater your risk of developing cancer or other health problems. This is why it’s important to discuss the need for any medical imaging tests that use ionizing radiation with your healthcare provider, and to make sure that the benefits of the test outweigh the risks.
How CTs and Radiation Work
First, some background: CT scans (also called CAT scans, or computerized tomography) is an x-ray that uses radiation to visualize internal structures of the body through a cross-section of images (unlike the flat images of normal x-rays). One CT scan is equivalent to about 100 chest x-rays. One perfusion CT scan (used to examine blood vessels and often used to diagnose stroke or aneurysm) is equivalent to several hundred chest x-rays.
Why? A CT scan uses X-rays, a form of ionizing radiation, to produce detailed images of the inside of the body. During the scan, X-rays pass through the body and are detected on the other side by a detector, producing data that can be used to create cross-sectional images of the body. The amount of radiation exposure from a CT scan varies depending on several factors, including the type of CT scan, the area of the body being imaged, the age of the patient, and the individual’s size and weight. All of this stuff has to be baked into the cake.
Many physicians have been concerned about the protocols for delivering x-rays and CT scans for years. A recent study by Dr. Rebecca Smith Bindman, published in the Archives of Internal Medicine, reports that there are significant variations in radiation dosage across many CT scans. Some machines provide 13 times more radiation than others doing the same job.
This is a long article. But stop and digest that. Do you want to be the person who gets 13 times more radiation than you need?
The study ralso eports that one in every 250 patients who have CT scans of the abdomen or pelvis will probably get cancer from the scan. Obviously, patients who receive higher doses are at a higher risk. An editorial in the same journal, by Rita Redberg, M.D., is here. Another study, by Amy Berrington de Gonzalez, et al., is here.
The FDA reports that it is investigating potentially defective CT scanners in three hospitals in Los Angeles County and one hospital in Huntsville, Alabama. They have received reports of 256 people who have received overdoses of radiation. In those hospitals, perfusion CT scans have incorrectly pumped radiation equivalent to several thousand chest x-rays into individual patients. There is no word on whether this was because of human error or machine error (the machines used were manufactured by GE Healthcare and Toshiba).
Questions You Can Ask
Some safety questions to ask your doctor and radiologist before you go in for scans include:
- Are there alternatives to this exam?
- Is this machine calibrated to my size, diagnosis, and region of the body being scanned (particularly important for children and infants)