Dr. Jeffry A. Siegel is an outspoken critic of radiation exposure awareness initiatives that assert that low-dose radiation exposure inevitably causes cancer, asserting there is no credible scientific evidence that medical imaging contributes to the development of cancer. In fact, he believes that efforts to lower dose exposure in medical imaging ultimately harm patients.

HealthCare Business News checked in with Dr. Siegel, who is president and CEO of Nuclear Physics Enterprises, an international nuclear physics consulting firm, to find out what his views are based on, why it matters and what it’s like championing these unpopular perspectives in an industry that has made dose awareness concerns one of its top priorities.

HCB News: Last year you published an article in the Journal of Nuclear Medicine titled "Dose Optimization to Minimize Radiation Risk for Children Undergoing CT and Nuclear Medicine Imaging Is Misguided and Detrimental." What is the key misconception that leads to these efforts?

Jeffry Siegel: There is absolutely no – zero – documented evidence of low-dose radiation harm. It’s a misnomer and a fiction based on the linear no-threshold model. I think people are afraid because of the atomic bombings at Hiroshima and Nagasaki. They equate high-dose radiation with low-dose radiation that we get every day from unavoidable background radiation exposure, traveling on a plane, from consumer products, from medical imaging, etc.

This can spawn radiophobia, where although the actual risks of a low-dose exposure are undocumented, parents become afraid to get their children scanned or physicians are afraid so they want to “optimize” the dose to make it as low as possible. There is true iatrogenic risk when physicians opt for a procedure that does not involve radiation because they’re afraid of the radiation, or use it at a lower exposure that results in nondiagnostic images.

HCB News: Can you elaborate a bit on the concept of the linear no-threshold (LNT) model and why you think it is faulty?

JS: High doses of radiation are known to cause cancer. Nobody would argue that fact. That’s true. There’s no question. The question then becomes what do you do about lower and lower doses?

The powers that be since the 1930s have said what you do is you take a ruler and draw a straight line from the known effects at really high doses, doses that people are not likely to receive in their lifetime, and draw a straight line to intersect the origin, that is zero, meaning that for any level of dose, there is a risk. Small, but there’s still a risk. That has never been documented to be true. A priori predictions abound without any a posteriori confirmatory observations. As newer analyses are done on the atomic bomb survivor population, it’s been found to be less and less true. Importantly, the body responds differently to high- and low-dose exposure. At low doses, repair of any damage is known to occur, thus invalidating LNT.

HCB News: Can you give us an example of a situation where a pediatric patient was harmed by efforts to reduce the amount of radiation they were exposed to?

JS: The answer to that is not known with any precision. Let’s say the image quality was nondiagnostic. The radiologist will read it and the consequence may be a misdiagnosis, the likelihood and harm of which are difficult to quantify.

Can I give you documented evidence of some child being misdiagnosed? You’d have to talk to radiologists who have been practicing forever and are now worried because images taken at lower doses may become nondiagnostic. Or they feel too pressured or constrained to recommend a CT, for example, and instead must choose MR or an ultrasound, which may not be as good for the study they need to get done.

HCB News: Your perspective on radiation can seem controversial for someone who has been hearing for years that reducing pediatric CT utilization is important for curbing cancer rates. Is it a challenge to convey your message without upsetting people?

JS: Of course it’s a challenge, but what’s controversial to me is that people believe that low doses are harmful. I would ask the question, what’s the proof? Where’s the evidence that low dose, not high doses from an atomic bomb blast, but low doses from everyday life such as airline travel and imaging involve a risk?

The Fukushima nuclear accident of 2011 is a modern example of radiophobia’s danger. They immediately evacuated 150,000 residents from the area. The doses that they would have gotten had they remained were so small that the United Nations subcommittee, UNSCEAR, publicly pronounced that nobody would have had any detrimental effect had they been allowed to stay in place rather than be forced to evacuate.

But what happened as a result of the evacuation? People got uprooted needlessly from their homes without any planning. They didn’t have access to the drugs or doctors they needed. Of the 150,000 people evacuated and not allowed to return home for years, 1,600 people died as a result of the evacuation, not the radiation exposure. They were old. They didn’t have their meds. They couldn’t go to their doctors. They became alcoholic. They committed suicide. Yet, that story hasn’t gotten out. Where’s that story?

HCB News: Is there any proven link whatsoever between administering multiple PET/CT or CT exams and the development of cancer?

JS: There is no documented evidence below 100 to 200 millisieverts. A CT scan is about 10. Can it happen? Is it probable? Could it possibly happen to someone among the billions of people who live in this world? Perhaps, but it is much more likely that the suspicion of cancer in the individual caused the CT rather than the other way around (known as reverse causation).

If you use a cancer risk estimate developed for relatively high doses from the Nagasaki or Hiroshima survivor population, multiply it by the radiation dose associated with a CT scan, and then multiply that by the millions of people who will get a CT scan, you will come up with a relatively large number of people who theoretically could develop cancer in 30 to 40 years. People have done that, but it is considered to be an inappropriate procedure. It’s based on the linear no-threshold model which is false.

Imaging has essentially replaced exploratory surgeries that resulted in actual, not predicted and undocumented deaths falsely assumed to result from low-dose exposures.

HCB News: What factors should providers and parents consider when the option of pediatric CT or PET/CT is being discussed?

JS: Again, they have to overcome this radiophobia. I don’t blame the patients or the parents. It gets reinforced time and time again by the media, regulators, misinformed physicians, etc.

Think about airline pilots and stewardesses. They get a pretty hefty radiation dose from natural radiation because they’re up in the cosmos all the time, where the radiation dose is higher. Yet, they’re not considered to be radiation workers like an X-ray tech, but they get, believe it or not, higher radiation doses than workers in nuclear medicine or radiology. And this dose is not regulated by anyone. There is no difference between natural radiation that is all around us and that from imaging equipment. There’s never been a study done to show that airline pilots are more susceptible to developing cancer than a plumber.

I think physicians have to act in the best interest of their patients, and if the best interest of their patient is they need to get a CT, the benefit far outweighs the only theoretical risk.

While it may seem logical to attempt to assuage the public’s fears by accommodating to their misperceptions and focusing on using the lowest dose possible, I contend that this will only reinforce their misperception. The public’s trust in medical practitioners can only be preserved if we can convince them (public and physicians alike) that there is little harm to begin with. Indeed, accurate information about low-dose radiation is the only way to undo the fears.