Posted on 09/19/2025 1:41:04 PM PDT by nickcarraway
Up to 10% of pediatric hematologic malignancies attributed to imaging-related radiation exposure
Key Takeaways:
One in 10 childhood blood cancers may result from medical imaging-associated radiation exposure.
Cancer risk increased with cumulative radiation dose, ranging from 1.41 times higher to 3.59 times higher.
Children exposed to at least 30 mGy had 25.6 excess blood cancers per 10,000 by age 21.
One of every 10 blood cancers in children may result from radiation exposure associated with medical imaging, according to a large retrospective analysis.
The risk of hematologic malignancy increased with cumulative radiation exposure versus none, ranging from 1.41 times higher for radiation doses of 1 to <5 mGy to 3.59 times higher for doses of 50 to <100 mGy. Cumulative radiation dose to bone marrow increased the risk of all hematologic cancers, reaching an excess relative risk of 2.54 per 100 mGy exposure. Other types of cancers also increased with imaging-associated radiation exposure.
For those exposed to at least 30 mGy of radiation, the excess cumulative incidence of hematologic cancers by age 21 was 25.6 per 10,000, reported Rebecca Smith-Bindman, MD, of the University of California San Francisco, and co-authors in the New England Journal of Medicineopens in a new tab or window.
A key takeaway from the analysis is to avoid unnecessary imaging in children.
"Our findings show that ionizing radiation from medical imaging is associated with a small but statistically significant increase in the risk of hematologic malignancy in children and adolescents, even at clinically common dose levels," co-author Diana Miglioretti, PhD, of the University of California Davis, told MedPage Today. "This underscores the principles of justification and optimization: imaging should only be performed when benefits outweigh risks, doses should be minimized, and when appropriate, non-ionizing alternatives, such as MRI or ultrasound, should be used. Medically necessary imaging, however, should never be deferred, as this could delay or miss diagnoses."
The findings did not come as a surprise, as the association between radiation exposure and cancer has been well established for years.
"Our study builds on prior research, such as the EPI-CT studyopens in a new tab or window in Europe, by providing more comprehensive evidence from a large North American cohort," said Miglioretti. "We included all imaging modalities (not just CT), used patient-specific dose calculations, and directly compared exposed and unexposed children to quantify risks more precisely. Unlike the EPI-CT study, we followed children from birth, enabling us to capture all imaging utilization and identify an unexposed comparison group. This allowed us to estimate the excess cumulative incidence of hematologic malignancies associated with varying exposure levels."
Much of the existing evidence about the linear relationship between radiation and cancer has been extrapolated from populations with higher-dose exposures, noted Lindsay M. Morton, PhD, of the National Cancer Institute, in an accompanying editorialopens in a new tab or window.
"The report ... is an important addition to the growing body of direct evidence regarding the small risks of cancer after low-dose radiation exposure," wrote Morton. "It also confirms the relatively short latency (interval between exposure and cancer diagnosis) of radiation-related hematologic cancers as compared with solid tumors and further raises the specter of radiation-related hematologic cancer risks beyond acute lymphoblastic leukemia and acute myeloid leukemia to other subtypes, such as non-Hodgkin's lymphoma."
Medical Imaging in the U.S.
The U.S. has the world's highest per-capita rate of diagnostic imagingopens in a new tab or window. Though essential for diagnosis and disease management, most types of imaging involve ionizing radiation, which is a known carcinogen, Smith-Bindman and team noted in their introduction. Multiple studies have shown a dose-response relationship between radiation exposure and cancer risk, with CT leading the way.
Children are particularly susceptibleopens in a new tab or window to radiation-associated cancer because of their higher radiosensitivity and longer life expectancy as compared with adults. The highest risk from radiation exposure is for hematologic malignancies, the authors said. Several studies have shown a 50% higher risk of hematologic cancers in children undergoing two or three CT scans versus one.
Research remains scant with respect to the risks in North America or to radiation exposure from radiography, fluoroscopy, angiography, or nuclear medicine. To investigate the issue, Smith-Bindman and colleagues analyzed data from the Risk of Pediatric and Adolescent Cancer Associated with Medical Imaging retrospective cohort study.
Data encompassed 3.7 million children born between 1996 and 2016 in six U.S. healthcare systems and in Ontario, Canada. They were followed until development of a malignancy or benign tumor, death, end of healthcare coverage, age 21, or Dec. 31, 2017. Mean follow-up was 10.1 years, representing 35.7 million person-years of follow-up.
The investigators documented 2,961 hematologic cancers during follow-up, primarily lymphoid cancers (79.3%) or myeloid cancers/acute leukemia (15.5%).
Key Findings
Average imaging-associated radiation exposure was 14.0 mGy overall, and 24.5 mGy among children who developed hematologic cancers. For context, the authors noted that a single CT scan of the head involves radiation exposure of 13.7 mGy.
The data showed a dose-dependent relationship between radiation exposure and cancer risk (as compared with no radiation exposure):
1 to <5 mGy: relative risk (RR) 1.41 (95% CI 1.11-1.78)
15 to <20 mGy: RR 1.82 (95% CI 1.33-2.43)
50 to <100 mGy: RR 3.59 (95% CI 2.22-5.44)
The risk of all hematologic cancers and most tumor subtypes increased with cumulative radiation dose to bone marrow. For hematologic cancers, the excess risk per 100 mGy radiation exposure was 2.54 (95% CI 1.70-3.51, P<0.001), and the risk was 1.76 for a cumulative radiation exposure of at least 30 mGy. Associations decreased with increasing time since radiation exposure, and were stronger in children exposed at 5 years of age or older.
Excluding children with Down syndrome, cumulative exposure of at least 30 mGy was associated with a cumulative incidence of hematologic cancers of 39.9 per 10,000 children versus 14.3 for children with no exposure, resulting in 25.6 excess cancers per 10,000 children. The cumulative incidence increased to 55.1 per 10,000 for cumulative radiation exposure of 50 to 100 mGy, or 40.8 excess cancers per 10,000 children.
Calculations for population-attributable risk of hematologic cancers in children and adolescents showed that 10.1% of the cancers resulted from imaging-associated radiation exposure. Charles Bankhead
Charles Bankhead is a senior editor, with primary responsibility for oncology, as well as urology, ophthallmology, and dermatology. He joined MedPage Today in 2007. Connect:
Sorry, Medpage got me again,
Ping
Why would you do unnecessary imaging of children in the first place?
It is not the 1950s where the foot x-ray machine is a cool free toy to play with.
All imaging costs money. Lots of it. So who are these people taking their kids in for funnzies?
I don't think parents are doing it for funzies, except maybe MBP parents. But some doctors/groups like to do a lot of test. It would be an interesting analysis of why they are ordered.
Safe and effective.
Begs the question as to why the kids are get 2-3 CTs to begin with. If they are already suffering serious illness in childhood, it’s not that surprising to see illness later.
Everybody’s tires wear a bit differently. It depends on the car you start with and the roads you take. It could be that, in this study, it’s more the car than the roads.
This reads to me like anything other than the CoupFlu vaxxes...
Which scans?
CT and what else?
Like a possibly broken bone. Which in kids can be strangely hard to detect. Broken, cracked or just strained can all show pretty much the same on the surface.
Maybe we have just been lucky with our pediatricians but one cub has ever needed a medical scan. Turned out, yes, broken but non-displaced.
Probably the reason for the increased/necessary imaging 😩
but no matter,we in western societies,pushed by big pharma and the medical industrial complex and their lawyers seek too often to use multiple medical treatments to our detriment,when simple patience and good nutrition would work.
I hear the ancient Mexican Aztecs had a special Sun God ceremony that was their "go to" cure for everything.
Anyone remember those x-ray machines in shoe stores that would image your toes in the new shoes?
I’m nearly 67. I’ve never had a CT or MRI scan.
It is my understanding that digital x-rays involve less radiation than film x-rays.
“3.7 million children...2,961 hematologic cancers”
The risk is lower than simple division would indicate, but it does seem to be considerable.
My next CT happened at age 50. I read the interpretation that included a humorous comment (to me) that the image was difficult to interpret due to a "paucity of fat". I weighed 145 lb at a height of 5 ft 11 in. 9% fat.
The next CT encounter happened at age 67. It would be one of many examining my liver, pancreas and duodenum. An MRI and ERCP as well. Suspicious "nodes" on my lungs too. After the Whipple procedure to remove the duodenum and cancer, more CTs to follow up post operative infections.
The last CT PET scan occurred in June of this year. The goal was to find any abnormal uptake of glucose indicating active cancer. Only a small "abnormal" rate was seen where my stomach was sewn onto the jejunum. Just on the edge of "normal".
I had additional fluoroscopic style exposures while placing drains to remove blood from my peritoneum after a nick renal artery bleed out and pocket of infection between my liver and stomach. CT of my lungs as well due to MRSA pneumonia. Hopefully I'm finished with the CT scans and they haven't triggered more problems.
A CT scan is like a whole bunch of x-rays. So that is why it would be more harmful than just a single x-ray.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.