Cancer Risk from CT Scan Radiation

The greatest radiation exposure risk comes not from the Fukushima fallout or the polonium naturally found in all seafood (see my last video, Fukushima and Radioactivity in Seafood), but from doctors. This was the study that originally shook things up: “Estimated Risks of Radiation-Induced Fatal Cancer from Pediatric CAT scans.” Researchers concluded that the best available risk estimates suggest that pediatric CT will result in significantly increased lifetime radiation risk. How increased? In the United States, of the approximately 600,000 abdominal and head CT scans annually performed in children under the age of fifteen, 500 of these individuals might ultimately not just get cancer but die from cancer attributable to the CAT scan radiation. In response to this revelation, the editor-in-chief of the leading radiology journal admitted that radiologists have not been watching out for children.

The cancer estimates were based on data from Japanese atomic bomb survivors, in terms of how many deaths one can expect from what kind of radiation dose. However, there’s never been a study able to actually document the excess cancers—until now. It turns out that the X-rays released by CAT scanners may be twice as carcinogenic as the higher energy gamma rays released from atomic bombs. Just a few CT scans may triple the risk of brain tumors and leukemia in children.

Other studies are being performed around the world to quantify the risk, and should be out in the next few years. Until then, what can we do? First of all, we should get X-rays only when absolutely necessary. Good evidence suggests that between a fifth and a half of CAT scans aren’t necessary at all—they could be replaced with another type of imaging or not performed at all. That’s a lot of added cancer risk for no added benefit.

If you click the above video, you can see the risk of developing cancer for different groups after getting one CT scan. The risk of developing cancer after a single CT scan may be as high as 1 in a 100 for a baby girl. It can take years for cancer to develop, though, which is why the risk is lower in the elderly since they have fewer years to live. The diagnostic medical radiation dealt out in one year is estimated to cause 2,800 breast cancers among women in the United States, and 25,000 other cancers. That’s doctors causing a lot of cancer.

One chest CT scan is like getting 400 chest X-rays, and a stress test heart scan can be like getting over a thousand X-rays. Doctors need to communicate the risks of these procedures, using relatable analogies. For example, the risk of a chest CT is like the risk of having a car crash during 2500 miles of highway driving or of smoking 700 cigarettes. You pick up a pack of cigarettes and there’s a warning label, but then you go in for thallium heart scan, and no one minds telling you that the risk corresponds to smoking 1400 cigarettes. Furthermore, 1 in every 270 middle-aged women that get an angiogram may get cancer because of that one test.

The risk associated with the thallium heart scans shocked me. By eating healthy, we may not only eliminate the death and disability associated with heart disease and its treatment (such as open heart surgery), but the risks associated with heart disease diagnosis as well. See these videos for my advice on preventing heart disease:

As I explain in my full-length live presentation on preventing, arresting, and reversing the 15 top killers (Uprooting the Leading Causes of Death), adverse drug reactions from prescription drugs are estimated to cause more than 100,000 deaths in the United States every year, making doctors the sixth leading cause of death. And that’s not counting other “iatrogenic” (physician-caused) harm, such as medication errors or infections acquired in hospitals. My profession needs to do a better job of offering fully informed consent, clearly and comprehensively explaining the risks and benefits of each alternate course of action.

What about cell phone radiation? See my video Do Cell Phones Cause Cancer?

And what about getting X-rays at the dentist? I’ve got a video about that too: Do Dental X-Rays Cause Brain Tumors?.

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death and More Than an Apple a Day.

Eating Green to Prevent Cancer
How Do Plant-Based Diets Fight Cancer?
Reversing Heart Disease


Eternal Gardener
Eternal G4 years ago


Donna Ferguson
Donna F4 years ago


Danuta Watola
Danuta W4 years ago

Thank you for the article

Don Swanz
Don Swanz4 years ago

I was recently diagnosed with "Stage 4 lung cancer", a stage that I never should have arrived at. Even though I was a smoker for 40 years - quit 18 years ago - had two (2) bouts of pneumonia and numerous lung infections over the years, my PCP; along with 1000's of other doctors, was reluctant to schedule me for routine or any other "chest x-rays" because of the danger of the radiation from the x-rays causing cancer. Just one (1) chest x-ray 12 to 18 months ago, would have spotted the cancer long before it reached "Stage 4".

Since being diagnosed, I've had to date; four (4) CT scans; one (1) PET scan; one (1) bone scan and one (1) brain scan with more to follow.

Now, where does THAT ONE (1) CHEST X-RAY that could have avoided this fit in.

I might add, that the US Preventive Services Task Force and the American Cancer Society are now recommending low dose CT scans for individuals in my age group 55-79 with similar histories. Too late for my; but I hope not for you. Don and I CAN! :-))

Vicky P.
Vicky P4 years ago


Don Swanz
Don Swanz4 years ago

LYNNI C: Seems to me, that your neighbor needs to find a new doctor. I recently "fired" my "pulmonary" specialist for that very season which was one of my better medical moves. Write down questions that you want to ask your doctor. Take pen and paper with you to all office visits. Write down the answers you receive. I "google" just about everything from questions you want to ask; symptoms; drugs - especially side effects - even your doctors qualifications. Don and I CAN! :-))

Lynn C.
Lynn C4 years ago

Thank you so much for the warnings! The Dr.s don't 'see' patients any more...their attention is totally on the computer screens and test results. I've taken my neighbor to the doctor and hospital and they asked "what are you here for?" and if you don't have a specific symptom they just throw another test at you and say "see me in six months" don't feel any better than when you arrived and you've been exposed to more rads. What a "health" system huh?

heather g.
heather g4 years ago

Dr Michael Greger you have a way of keeping us on our toes........

Don Swanz
Don Swanz4 years ago

TSANDI C: You comment on belittling Fukushima was out of line. No where in the post did this occur. Did you watch the video: Fukushima and Radioactivity . . . . . ? Next, if you want any kind of credibility, update your home page and provide us with some references for your claims.

That being said, I do believe that I'll be reducing my consumption of fish. Don and I CAN! :-))

Edith B.
Edith B4 years ago

Something else to worry about. Sheesh.