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Posts Tagged ‘radiation’

Some Unexpected Stuff From Japan’s Nuclear Crisis

March 15, 2011 Leave a comment

As Japanese officials are attempting to cool the reactors at the Fukushima Daiichi nuclear plant, which was damaged after the devastating earthquake and ensuing tsunami last week, some unexpected things have been happening as a result of the fear from this situation.

In an effort to help Japan conserve its electricity, game developers Konami and Square Enix will be suspending online access of their games to Japanese consumers for the time being.

Square Enix operates MMORPG games Final Fantasy XI and Final Fantasy XIV, and Konami operates Metal Gear Online.

How much electricity this will actually save is a difficult question to answer, but in times of crisis I suppose that every little bit helps.

In another development, Germany has temporarily shut down 7 of its nuclear power plants.

“We want to look at the risk and safety issues in the light of events in Japan,” the European energy commissioner Guenther Oettinger said.

While I can understand the desire for safety, particularly in light of the media-driven fear of radiation contaminating the rest of the world, I think this action is not only an over-reaction, but it adds fuel to the fire of radiation fears.

This also comes in the face of a massive anti-nuclear protest in Germany, which was already planned prior to the devastation in Japan,

Protesters in Stuttgart formed a human chain reaching 45km (27 miles) for the event, which had been planned before the current nuclear crisis in Japan because it was already a key election issue.

Switzerland has also suspended decisions on its current nuclear power structure to re-evaluate its country’s energy plans.

This is quite baffling to me because nuclear energy is one of the cleanest and safest forms of energy production. It is not exactly fair to use the Japan situation as a case against nuclear power, seeing as it was recently hit by and 9.0 magnitude earthquake AND a tsunami.

The Japanese crisis is indeed serious, but unique. It actually wasn’t the earthquake or the tsunami which directly caused the explosions. It was an unfortunate failure of the backup power systems to the power plant which prevented cooling water from circulating, which then caused overheating and eventually an explosion.

So I don’t believe that blaming the nuclear boogeyman is the right way to react to this scenario. Disasters do happen and there are unforeseeable consequences. And as I write this, the containment structures of the reactor cores have not yet been breached, and the Japanese are attempting to cool them by flooding the structures with seawater.

Much like the Three Mile Island scare, the potential for damage is there, but no large amounts of radiation have been released yet.

Unfortunately, solar and geothermal power are not quite ready to meet the world’s energy needs yet. Wind power is starting to be criticized because of its environmental impact. So for the time being, nuclear power remains our best bet for environmentally conscious energy production.

Cell Phones, Your Brain, and the Media

February 23, 2011 72 comments

Usually, when a scientific study gets this much media attention, it has something quite impactful to report.

But when the study has nice, media-friendly buzz-words like “radiation” and “brain activity”, you get a firestorm of media coverage. Even if your study doesn’t say all that much.

The study I am referring to is called “Effects of Cell Phone Radiofrequency Signal Exposure on Brain Glucose Metabolism” which was recently published in the Journal of the American Medical Association.

The study looked at 47 healthy volunteers; a relatively small study. The researchers took these volunteers and gave them all PET scans on their brains. They had also strapped two cellphones on either side of their head. One cell phone was on, and the other was turned off.

During a 50 minute phone call, they compared the two sides of their brain to see if there was any change in glucose uptake.

What did they find?

Whole-brain metabolism did not differ between on and off conditions. In contrast, metabolism in the region closest to the antenna (orbitofrontal cortex and temporal pole) was significantly higher for on than off conditions (35.7 vs 33.3 μmol/100 g per minute; mean difference, 2.4 [95% confidence interval, 0.67-4.2]; P = .004). The increases were significantly correlated with the estimated electromagnetic field amplitudes both for absolute metabolism (R = 0.95,P < .001) and normalized metabolism (R = 0.89; P < .001). [JAMA]

So basically, whole-brain metabolism was the same whether the phone was on or off. However, in regions close to the phone’s antenna, the metabolism was “significantly higher”. It is important to point out that in this context, “significantly” means statistical significance, not a large increase. In fact, the increase was only about 7%.

Brain imaging physicist Dardo Tomasi of Brookhaven National Laboratory, who co-authored the study, said that’s several times less activity than visual brain regions show during an engaging movie. [Wired]

Ok, so now the important question: what does this mean for our health? Nora Volkow, the study’s lead author commented:

Volkow says it is too early to tell whether this is good or bad for the brain. “Much larger fluctuations in brain activity occur naturally,” says Patrick Haggard at University College London. In fact, being able to increase activity might boost the brain’s connectivity, and could even be useful therapeutically, Volkow suggests. [New Scientist]

So although the study was published as a “Preliminary Communication”, and that the study itself concludes:

This finding is of unknown clinical significance. [JAMA] (emphasis mine)

there is still a large number of news outlets which reported on the study. Why?

Well we know why already. That “unknown” word in the above quote carries a lot of baggage.

Cell phones are the new danger to health, of course. Despite there being no conclusive evidence that cell phones even have the ability to cause cancer, and the fact that even with the explosion of cell phone use in recent years, cancer rates have not increased, people are still scared of their cell phone.

This is thanks to poor media coverage, and a few crackpots out there who are determined to prove that technology is going to destroy us all.

And as a result this small, preliminary study with a result that, while interesting, is completely benign, gets extensive media coverage. Not only that, but some news sites give thinly veiled comments suggesting that the results somehow show that cell phones are dangerous, like this one:

The unusual finding, published on Tuesday in the Journal of the American Medical Association, is likely to lead to new calls for stricter regulation of radiation emissions from the ubiquitous phones. The government currently assumes the signals have no effects other than a harmless warming of tissues near where they’re held. [The Globe and Mail]

or this one:

Some studies have linked cell phone exposure to an increased risk of brain cancers, but a large study by the World Health Organization was inconclusive. [MSNBC]

Of course they used the word “inconclusive” in the above quote, when it should really read “it showed no correlation”. Scicurious points out that this is probably because “‘inconclusive’ sounds scarier”.

So nobody panic. This study does not show that cell phones are dangerous. It may show that the electric field from the antenna somehow increases metabolism of glucose, but those findings need to be corroborated by other labs. Let’s wait until their findings are duplicated on a larger scale and a mechanism by which this effect happens can be discovered before we decide what, if any, impact this study should have.

Do Cell Phone Towers Make Women Pregnant?

December 23, 2010 3 comments

A Typical Cell Phone Tower, via Wikimedia Commons.

That is what the data is showing.

Using publically available data on the birth rates of communities, Matt Parker, who writes for The Guardian, did an analysis of the data and found this remarkable correlation. On average, there were 17.6 more babies born above the national average in the area around a cell phone tower.

So are cell phone towers actually causing women to get pregnant?

No.

And that’s the point.

On his blog, Parker is trying to make the point that correlation does not equal causation, which is almost a mantra for skeptics. Recent hysteria regarding WiFi and Cell phones has prompted many skeptics (including yours truly) to blog on the subject and express their displeasure. Not only with the quack “scientists” promoting this idea, but also with the media for callously reporting on it without proper research, only furthering the spread of misinformation.

Parker says,

There is no causal link between the masts and the births despite the strong correlation. Both the number of mobile phone transmitters and the number of live births are linked to a third, independent factor: the local population size. As the population of an area goes up, so do both the number of mobile phone users and the number people giving birth.

This is what is known as an observational study. The study is not performed in a lab where variables can be controlled. It is performed by observing the real world and attempting to make sense of the data.

As you can see, it is quite easy to come to a false conclusion despite good data. Accounting for all variables in such a study is extremely difficult, and sometimes damn near impossible. Firm conclusions on a topic should never be drawn based solely on a study of this type.

It should go without saying, but there is no credible evidence linking wireless internet or cell phone use to health problems. This is junk science promoted by junk scientists, and spread through the naive media who care more about ratings and readers than reporting truth.

I really like that someone took the time to get make this point using real data. Hopefully, this will get as many headlines as stories about cell phones causing cancer do.

Do Cell Phones Cause Cancer? See What a Real Expert Says

November 24, 2010 6 comments

I’ve written about the issue of cell phones and Wi-Fi and the supposed health risks associated with their use. The resounding scientific evidence shows they are perfectly safe, but the media continues to stoke fear in the public with unbalanced coverage.

When reading a news story about this sort of thing, I always wonder why they don’t ask an actual expert. The answer is that an expert would say how implausible the story is, and that they are silly for reporting it.

That doesn’t sell newspapers.

Instead, they find the one person on the fringe who maintains that there is a magical mechanism by which non-ionizing radiation can harm us. But thankfully, Phil Plait posted on his blog today something I have been looking for a long time.

I’m not a researcher (anymore). I don’t have a Ph.D, so I can tell you what I think, and I can tell you I know what I’m talking about, but I will never have as much credibility as a real university professor in physics or electrical engineering.

Enter this talk by Professor Christopher Davis from the University of Maryland’s Department of Electrical and Computer Engineering. It was given at a National Capitol Area Skeptics meeting, and posted on YouTube. It’s in 5 parts and each part is about 13 minutes long.

It is a fascinating talk and not too technical, so you don’t need a science background to understand the main points. He even touches on backscatter x-ray scanners which have been in the news quite a bit lately. Enjoy!

Ontario Says “No” to Cell Phone Warning Labels

November 5, 2010 1 comment

And it’s the right call. For two reasons:

  1. There is no conclusive scientific data to support any adverse health risks associated with short, moderate, or long-term cell phone use.
  2. A warning label would serve no purpose, other than to instill fear into the users.

The bill proposed to put a sticker on all cell phones indicating that there could be an increased risk of cancer from using a cell phone. Not only is this unnecessary, but it’s also wrong.

The scientific data overwhelmingly shows that there is no increased risk of cancer associated with cell phone use.

And what purpose would a warning sticker on a cell phone serve anyway? Would any of us stop using our cell phones? Would we hold it further from our head while we talk on it?

Of course not. Eventually we would get over our initial shock and fear of the warning sticker, read all the buzz-word containing media-frenzy stories about the evils of technology, and then settle back into our normal routine. All in all, this was a bad idea to begin with.

But my oh my, look who turned up to give her opinion on this issue. Our old friend Prof. Magda Havas from Trent University. She turns up in just about every story that involves cell phones, wireless internet, power lines, dirty electricity, and many other stories trying to convince us that technology is bad.

So I want to get something straight about why she keeps showing up. Is it because she is an expert? I would argue not. Her Ph.D. is in botany (the study of plants) so I don’t see how this qualifies her to study electromagnetic fields and their interaction with the human body. The list of publications on her website has very few peer-reviewed articles. Instead, it’s littered with “Letters to the Editor” and other opinion based writing. Not a lot of scientific credibility there.

No, she shows up because media outlets try to get both “sides” of the story, even if one side is way off base. Enter Magda Havas, who is one of very few people in the world who believes in electrosensitivity and kids getting sick from wireless internet. There are so few people who think this way, that they keep going to one person on the fringe to get her opinion. It is sloppy reporting, and not indicative of the evidence.

On CSI, Grissom (who was the best character but left, and now I am sad) always tells us to “follow the evidence” because the evidence will lead us to the truth. If we follow the evidence about cell phones, we see overwhelming evidence that cell phones are safe. Why then, do we continue to read about how evil they are?

William Peterson as Gil Grissom. From Wikipedia

Be Afraid of Your Wi-Fi! Be Very Afraid!

September 1, 2010 Leave a comment

Wow. I cannot believe this is still in the news.

Its one of those things you hope only happens once and you never hear about it again. Like the Star Wars Holiday Special.

But unfortunately, the Wi-Fi hysteria remains in the news. This time with a couple of new foot soldiers. They include a drama teacher from Brock University, and a self-proclaimed specialist named Barrie Trower.

And perhaps I shouldn’t be surprised, but the reporting of this story in the CBC is really starting to irk me. Lets explore shall we?

I wrote previously about the parents in Simcoe county in Northern Ontario were claiming that Wi-Fi was making their children sick. The supposed dangers of Wi-Fi has been dismissed by teachers, the World Health Organization, Health Canada and scientists worldwide; as it should be.

But proponents of the evils of technology continue to drag the story out and spread fear throughout the community. With a little help from their friends, the news media.

Take, for example, this audio clip of an interview on CBC with Barrie Trower.

Barrie Trower on CBC Metro News

Trower claims to have worked for the British military in the 1960s on experiments dealing with low-level microwave radiation. He claims that they caused adverse health effects; everything from affecting the blood brain barrier to the immune system. He is quite vague and never explains what frequencies or power levels of microwaves he studied.

A couple of my favourite quotes from the audio file are these:

I have a document here…it lists all of the illnesses that  children and adults can get from very low-level microwave radiation. And it specifically says on the top…this must be kept secret…the ordinary general population must not be told because it will affect industrial profit.

What is this document? Who wrote it? There are no specifics given about the origin of this mysterious document. Trower claims he gets it from the freedom of information act, but if that were true he should have given us the specifics so we could look up the document for ourselves. I am skeptical…

When I saw Wi-Fis being put in schools at the same powers and the same levels that were used in the 1960s for experiments, I knew straight away that there were hidden dangers to the young children.

You knew straight away, did you Mr. Trower? What about when Wi-Fi was being put into offices, Universities, laboratories, airports, and coffee shops? Did you not think there was a danger then? It seems interesting to me that only when the story about the Simcoe area parents came out, did Mr. Trower decided that he should reveal to everyone about the secret 50 year old experiments that he did with microwaves.

Nor has Mr. Trower provided and clear arguments or evidence (at least, to the news outlets) that Wi-Fi poses any sort of threat to anyone.

And what about the other British scientists that performed these experiments? I find it odd that they all wouldn’t want to come out and save chidren’s lives if they thought that Wi-Fi was dangerous.
While the interviewer sounds slightly skeptical, he fails to ask the right questions to point out the weaknesses in what this man is saying, so thats YOUR fault CBC.

Now lets move on to the drama teacher from Brock University, one David Fancy. Said Fancy,

It’s not necessarily up to me to say that they cause harm. I think there’s a lot of evidence to suggest that they do. But we certainly can’t say with any conclusive level that they’re safe.

Actually David, yes we can. There is a large body of literature which has studied and reported the effects of exposure to microwave radiation. The conclusion is that at the frequencies and powers associated with cellular phones, cell phone towers and Wi-Fi, the exposure level does not pose any danger.

In fact, 1 years worth of exposure to a wireless signal is roughly the same exposure as you would get in a 20 minute cell phone call. And in a recent large scale study, the long term effects of cellular phone use has not shown any mal-effects over the past 10 years.

Now, just to be fair, there is a small smattering of studies which suggest a health effect from low level microwave exposure, which these fear-mongerers can spout of the top of their heads. However, one has to take into account the entire volume of literature, not just a few isolated studies (most of which have had their conclusions contested).

You see, when a subject is studied as much as RF radiation, there is bound to be some random noise in the results of individual studes; particularly if the studies involve small sample sizes. This is completely expected. What is important is what the overall picture of the studies is, and that picture is that Wi-Fi is safe.

You can all relax now.

This all would be clear in the news stories, if the news outlets bothered to get an actual expert opinion. Why haven’t the CBC gone and interviewed physics Professors or doctors or biologists or RF engineers? Doesn’t this seem like an obvious thing to do?

Apparently not, and its having an effect. On a CBC poll about 1/3 of parents are concerned about Wi-Fi and its health effects. Kudos CBC on causing fear in these parents minds.

Sadly, talking to Physicists doesn’t boost ratings (unless maybe its Phil Plait) so we won’t get those opinions in the news. You have to go and search them out yourselves.

The Physics Of X-Ray Imaging

August 31, 2010 3 comments

So here is Part One of my series of the “Physics Of” medical imaging. First up is the most recognizable: X-ray Radiography.

Radiography (which uses x-rays, but the images are generally called “X-Rays”) are the most common form of medical imaging, and are incredibly useful. Thousands of images are performed everyday and medicine was revolutionized when this non-invasive means to study the body was discovered.

But how exactly do we get x-rays and use them for imaging?

Lets start with a bit of history. The first X-ray image was created by a guy named Wilhelm Rontgen in 1895.

Wilhelm Rontgen

Rontgen called them “X” rays because they were an “unknown” type of radiation, and the name kind of stuck.

The first image was of Rontgen’s wife’s hand, and is pretty cool because you can actually make out her wedding ring.

First image using X-rays of Wilhelm Rontgen's wife's hand

I actually find this a bit funny. I just picture a crazy looking physicist saying “Honey! C’mere! Stick your hand in front of this radiation for a second!”

Luckily for Mrs. Rontgen, x-rays, in small doses, are not very dangerous. So what exactly are x-rays?

X-rays are electromagnetic waves just like visible light, radio waves and microwaves. They have a wavelength range of roughly 0.01 to 10 nanometers (1 nanometer = 1 billionth of a meter).

When talking about x-ray imaging, however, its easier to think of x-rays in terms of photons. Photons are like tiny wave “packets” and electromagnetic waves can be described as a big collection of photons.

X-rays are generated in an x-ray tube (unsurprisingly). Basically, a bunch of electrons are shot at a piece of metal (usually tungsten, the same metal used in old school incandescent light bulbs). Now what happens next is a little complicated, but really cool…

So the electron travels at a certain speed toward the piece of tungsten; it has kinetic energy, which is the energy of motion. But as it gets close to the Tungsten it will run into an electric field produced by the metal, and will actually slow down.

X-ray Tube

Now, in physics there is principle called the conservation of energy. Basically this just says that energy can never be created or destroyed, it can only change form. So when the kinetic energy (energy of movement) of the electron drops (when it slows down) that lost energy has to go somewhere. Where it goes, in fact, is in the generation of an x-ray. The electron will actually emit an x-ray when it gets slowed down by the tungsten. Pretty sweet eh?

Schematic of X-ray tube. Electrons come in from the bottom, strike the tungsten target (the anode) and emits x-rays

This is actually a type of radiation called Bremsstrahlung, which is German for “braking radiation”.

Schematic Diagram of Bremsstrahlung

Ok, so now we got x-rays, how do we make an image?

Well, if we fire x-rays at, oh lets say, YOU! the x-rays will interact with your body. How you ask?

Well when an x-ray passes through the body, it may get absorbed or scattered by the body. An x-ray gets absorbed when the x-ray hits an electron in our body, and the electron “jumps” out of the atom. This is called the photoelectric effect.

The Photoelectric Effect

The x-ray may also get scattered. This just means that the x-ray will get close to the nucleus of an atom and get kind of turned in another direction due to the electric field of the nucleus. This is known as Compton Scattering.

Compton Scattering Effect

In spots of our body that very dense like bones, the x-rays have a much higher chance of getting absorbed or scattered than if they pass through muscle or fat, which are less dense. So if we were to stick a piece of film which is sensitive to x-rays behind someone getting a radiograph, you would get lots of x-rays hitting the film when they pass through muscle or fat, but very few pass through bones (or metal, if you’re really unlucky).

So on the radiograph muscles and fat show up dark, and bones show up white. BAM! Radiograph!

Chest Radiograph

See, now that wasn’t so bad was it? Pretty interesting if you ask me.

The next installment of my “Physics Of” medical stuff  series will be something that takes x-rays to the next level: Computed Axial Tomography, commonly called “CAT” scans.