Posted tagged ‘radiation’

Protect yourself from cell phone radiation journalists

May 31, 2016

The Pediatric Insider

© 2016 Roy Benaroch, MD

The media is agog over a new study, one tailor made for clickbaiting. Staid, boring old Wall Street Journal proclaimed “Cellphone-cancer link found in government study.” Mother Jones called the study “Game Changing”, and NaturalNews’s headline screams “Massive government study concludes cell phone radiation causes brain cancer.” (They also say “On all of these issues, Natural News has always been right!” Google it if you want. I’m not providing a link.)

The new data is from a preliminary release of data from 2,500 rats and mice. It hasn’t been peer-reviewed yet, or scheduled for publication. We have no idea what happened to the mice involved in this study – they weren’t mentioned. Maybe they were busy.

The rats were kept in an underground bunker (which protected them from the sun, a much larger source of radiation exposure.) Special enclosures exposed the experimental rat volunteers to cell phone radiowaves starting at gestation, through the first two years of their lives. Intense radiowaves bathed their entire bodies for 10 minutes on, 10 minutes off, 18 hours a day. For two years. Extrapolating from rat lifespans, that’s equivalent to about 50 human years. Think about that exposure: 50 years, starting before birth, using cell phones mashed up against your entire body for 9 hours a day. I get it, they want to use an absolutely maximal exposure to find even a small signal of increased risk. But does that sound remotely realistic?

Compared to the control rats, male (but not female) exposed rats had small numbers of cancers in their brains and hearts – in most groups, 1 or 2 out of 90. The control rats had zero across all of the subgroups, which is itself a surprise – these were lab rats bred to develop cancers, so cancer-causing exposures could be studied. The control (unexposed) rats also had a weirdly high early death rate (remember, this group didn’t have cell phones. They were bored to death, maybe.) In all seriousness, that seems to be a big flaw. Since cancer takes time to develop, rats in a shortened-lifespan group would almost certainly have fewer cancers at autopsy. Still – zero? Were they looking hard enough?

The new study certainly raises some good questions. How could radiowaves contribute to cancer? There’s no established plausible mechanism at these levels. Why were the results only seen in male rats? What about the mice, were they similarly affected? Why did the non-exposed rats die off early, and could that explain the effect? How do these exposures compare to a typical human way of using a cell phone, holding it in your hand to text or use an app? These are good questions. Too bad journalists covering the study didn’t try to answer them.

Ironically, just a few days earlier, a much larger study (of 45,000 people) showed exactly the opposite. What, you didn’t hear about the huge Australian study that showed no increased risk of brain cancers since the introduction of cell phones 29 years ago? Perhaps the science media is more concerned about rats than Aussies. They’re certainly more eager to get your clicks than to provide accurate or useful information.

A rat.


Protecting yourself from CT scans and cancer

August 19, 2013

The Pediatric Insider

© 2013 Roy Benaroch, MD

I’ve been writing a lot about CT scans lately. Why are so many being done, and which children with head trauma really need one? CTs are really kind of neat—it’s amazing that we can peer into your body to see what’s going on in there. But like every other medical intervention and treatment, there are positives and negatives, pros and cons, a ying and a yang.

I’ve mentioned some downsides to CT scanning: they cost a lot, and often reveal incidental things that though technically “abnormal”, are meaningless. But they still cause anxiety and further costs and more CT scans for follow-up! Still, the most important problem with CT scans from a public health point of view is that they involve exposing the patient to ionizing radiation, with a resulting increased lifetime risk of cancer.

CTs use x-rays to peer through your body, the same x-rays that are used to make plain x-ray pictures. But with a CT, a whole series of x-rays are taken one after another in little “slices.” Then a computer algorithm stitches those plain films together to get the familiar CT pictures of your insides. A single CT scan exposes the body to as much radiation as 200-1000 plain x-ray films—the bigger the body part, the more net radiation is needed.

And the more radiation used, the more likely there is to be mischief. Every ionizing particle has a chance to knock into your DNA, causing damage that can lead to cancer. Now, your cells already have mechanisms in place to repair this sort of damage. But it doesn’t work 100% of the time, and the more radiation, the more damage, and the higher the chance that an important DNA change will slip through the cracks.

Your body, it should be said, is bathed in radiation every day. There are radioactive elements in the earth’s crust, and there are cosmic rays pelting your scalp even as you read this. Your body can repair the damage, almost 100% of the time. But if you add a lot of excess radiation—from occupational exposures for pilots or radiologists, or from medical diagnostic studies in a CT scanner, you increase your risks.

About 2% of the total 1.7 million cancers in the US are thought to have been caused by diagnostic radiation. Another way of looking at this: one case of extra cancer is caused by every 400 to 2,000 routine chest CT scans. That’s a broad estimate, and it illustrates how difficult it is to really pin down the risk of these studies.

The problem is that estimates of cancer rates are largely based on atomic bomb survivors, who were exposed to far more radiation and have experienced a large increased cancer rate. From them, researches have extrapolated backwards—smaller radiation doses leading to smaller, but real, increased cancer rates. But we don’t really know if this is a simple linear relationship. Do smaller radiation doses increase cancer rates proportionally, or higher or lower than relatively high doses? It is very difficult to know, because we’re talking about small exposures and small increases in population risk. But when you apply that risk to millions of people, you’ve got a significant quantity of cancers potentially triggered by well-intentioned medical testing.

As a pediatrician, I’m especially concerned. My patients have more years to live than adults, so more years to potentially develop cancer; also, their smaller bodies might provide less shielding from radiation. Because their cells are growing, their DNA may be more vulnerable to the damage caused by radiation as well.

So, what can patients and parents do to limit risk?

First, reduce studies, especially CT scans. Many are being done unnecessarily. Just a few minutes discussion may help doctors and patients understand that a CT scan does not need to be done.

Reduce doses. Newer CT technology relies on lower radiation doses. Special equipment can be used on children to further limit exposures.

When practical, choose imaging studies that do not use ionizing radiation. This includes MRI scans and ultrasounds—which do not involve any increased risk of cancer. However, these studies have their own limitations and may not always be practical or realistic substitutions.

Limit studies to the area of interest. If you have a lump in your wrist, you don’t need a CT scan of your entire arm; someone being evaluated for liver inflammation doesn’t need a CT scan that goes down to their pelvis. Also, keep in mind that some areas of the body seem inherently more at-risk for radiation damage—such as the thyroid and gonads. Those areas should be shielded or avoided if possible.

CT scanning is a life-saving, crucial medical tool. When used appropriately, it’s one of the most powerful ways we have of confirming diagnoses and evaluating potentially catastrophic problems. But they do have a down side. Doctors and patients need to discuss CT scans as they would any other medical treatment, their risks and benefits, options and alternatives, and whether they’re really needed, before the tests are done.

Scary Rays from the Sky

April 30, 2010

The Pediatric Insider

© 2010 Roy Benaroch, MD

From Katie: “Any thoughts on cell phone towers being placed on an elementary school’s property?”

Radiation. Powerful enough to turn Dr. Bruce Banner (Bill Bixby) into The Incredible Hulk (Lou Ferrigno), or meek Peter Parker (Tobey Maguire) into The Amazing Spider-Man (still Tobey Maguire, but more buff and spandexed). It also obliterated two cities in Japan, and continues to contribute to cancers near Chernobyl. It’s sciency, strong, and scary. No wonder it creates so much apprehension.

We’re all living every day surrounded by radiation sources, and bathed in radioactive rays. Cosmic rays are a significant and unavoidable source of radiation from above, and naturally occurring forms of radon, carbon, and many other elements in the earth’s crust bombard us with radiation from below.

Not all radiation is the same. The more-powerful, cell-damaging kind is called “ionizing radiation,” and we know that can strip atoms apart and disrupt DNA. This kind of radiation occurs in cosmic rays and diagnostic x-rays, and that’s why radiology technicians wear lead overcoats. It is a bad idea to be exposed to excessive ionizing radiation, though even that risk should be put in perspective, since you can’t possibly avoid it entirely. For comparison, a single chest x-ray exposes an adult to about the same ionizing radiation that you’d get in three days of living on the earth at sea level. Three days, that doesn’t sound so bad. But an abdominal CT scan? That’s about three extra years. Diagnostic radiology is a wonderful tool, but it should be used carefully.

The other kind of radiation is called “non-ionizing.” You’re swimming in that, too. All light is a form of non-ionizing radiation, as are radio waves and microwaves. Though at very intense, high exposures these kinds of radiation can damage tissue (think about a microwave oven, or spending a day in the sun), the process of damage is by the transfer of heat, not the destruction of DNA or other molecules directly. And it only takes a very thin layer of shielding to protect from even intense non-ionizing radiation. You can get a sunburn, yes, but you won’t burn through a thin piece of clothing or a layer of sunscreen, and a little piece of darkened plastic can make squinting unnecessary even on a bright day. Non-ionizing radiation doesn’t penetrate tissue well, and that’s one reason it’s thought of as generally safe.

Cell phones themselves use non-ionizing radio waves to communicate with their towers, and that radiation can barely penetrate the topmost payer of your skin. The most recent research has found no link between cell phone use and cancer, though good studies of more than ten years exposure have not been done. Certainly, if there is a risk, it’s very small; a large risk effect would be easy to spot in demographic and population trends, and it just isn’t there.

Cell phone towers transmit in both radio waves and microwaves, though the microwaves are directed to travel along lines of sight to the next tower– they don’t point down towards the ground at all. There is no credible evidence that they cause any direct harm. At least not from their radiation.

The real risk, of course, is automobile accidents. Car wrecks kill about 45,000 people in the USA every year. How many of these are caused by drivers distracted by a cell phone?

For a while, high-voltage electric transmission lines, which also emit electromagnetic radiation, were implicated as a cause of cancer and other bad things. After decades of research failed to find real evidence of any harm, the anti-power line crowd seems to have moved on to cell phones as the latest health boogeyman. (For more about the story of epidemiology and the rise and fall of the hysteria over health risks from power lines, read Geoffrey Kabat’s Hyping Health Risks.)

Don’t fall for the hysteria over cell towers. Careful studies have so far been able to rule out any large effect; though tiny effects are still possible, good research is being done to see what the extent of that might be. In the meantime, if you want to be safe around cell phones, don’t use them when you’re driving. That’s a much, much bigger health risk than could possibly be associated from the Scary Rays from The Sky.