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Dental X-Rays Linked To Common Brain Tumor

timothy posted more than 2 years ago | from the tradeoffs-are-everywhere dept.

Medicine 248

redletterdave writes "A new study suggests people who had certain kinds of dental X-rays in the past may be at an increased risk for meningioma, the most commonly diagnosed brain tumor in the U.S. Dr. Elizabeth Klaus, the study's lead author and a professor at the Yale School of Medicine, discovered that dental X-rays are the most common source of exposure to ionizing radiation — which has been linked to meningiomas in the past — and that those diagnosed with meningiomas were more than twice as likely as a comparison group to report ever having had bitewing images taken. And regardless of the age when the bitewings were taken, those who had them yearly or more frequently were between 40 percent and 90 percent higher risk at all ages to be diagnosed with a brain tumor."

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248 comments

Cancer... (0)

Anonymous Coward | more than 2 years ago | (#39630681)

...the new reason to be afraid of the dentist.

Re:Cancer... (3, Informative)

Anonymous Coward | more than 2 years ago | (#39630747)

My father was a dental technician (he made dental crowns) and he always refused to get x-rays when he went in for his check-ups. My physics professor in undergrad told me the same thing - only get dental x-rays when absolutely necessary. Bone does a good job of scattering x-rays all over the place, and your skull and jaw, believe it or not, are composed of a great deal of dense bone.

Re:Cancer... (4, Insightful)

Bengie (1121981) | more than 2 years ago | (#39631411)

Modern techniques only use 1/100th the amount of radiation of machines from only a decade ago.

I guess my question is how does the new tech affect people. If the old tech only doubled the tumor rate, reducing the amount of radiation by two magnitudes should lower your risk quite a bit.

Also, the machine at my Dentists doesn't do the whole head, but has a VERY focused output that pressed up against your cheek. You place a digital x-ray sensor between your teeth and it works as a "film".

They're like, "we don't even have to leave the room anymore". They stand right behind the machine.

Re:Cancer... (5, Informative)

Zibodiz (2160038) | more than 2 years ago | (#39631925)

That's a total lie. They use exactly half. Source: I'm a certified dental x-ray technician.
'New' digital sensors require the same amount of X-Ray radiation, but for half the amount of time (for bitewings, that's about 100ms instead of 200ms), but since they're so quick to scan in (i.e. the Dentist doesn't have to wait for them to develop), if they aren't exactly perfect, dentists will often ask for re-takes. The average was 5 or 6 images on each patient. I was pretty good and usually only had a re-take every 3rd patient or so, but the other x-ray technician I worked with would often take 4 or 5 re-takes on a single patient. All-in-all, that means they got more radiation than if they had just gotten the traditional x-rays.
I should point out, though, that the Dentist told every patient (and told us to tell them, as well) that they only get 1/100th of the radiation. It's just a party lie.
As far as the 'pointed beam' you're talking about, that hasn't been improved, ever. The cone is just as large as it's always been. If the technician stands in the room (as my co-worker often did), they're just stupid. In fact, according to ADA recommendations, X-Ray techs are supposed to wear dosimeters. Most dentists are too cheap to buy them, though.
The 'Bitewing' x-rays that this article is about are exactly the kind that are close to your cheek. There are 3 types of dental x-rays: Bitewings, which shoot the radiation between your molars and premolars, and are used to diagnose cavities between yoru teeth. PA's, which are used to view your entire tooth, including the entire root and an area of bone beyond it. These are useful for diagnosing a toothache, because if the toothache is caused by an infection at the apex of your root, it will be visible. That, in turn, means a root canal. The third is a Panoramic, which is the kind that wraps around your entire head, and shows all of your teeth in one shot. These are beneficial for things like getting an 'aerial view'; they don't show a lot of detail (not enough to diagnose a cavity), but will show things like impacted wisdom teeth, and are useful for Orthodontists.

Re:Cancer... (2)

mspohr (589790) | more than 2 years ago | (#39632083)

Modern x-rays (digital) use about 1/3 of the radiation of older "E-speed" (high radiation, high definition) film so your estimate of 1/100 is an exaggeration.
In addition, the "very focused" radiation beam can be a problem since even a small amount of radiation is delivered to a small area.
Standing behind the machine is probably safe. I would hope they would shield the back of the machine. However, the patient is in front of the machine and is the target of the radiation.
Radiation is bad in any amount and it doesn't do any good to deny this fact. Instead, we should all look for ways to avoid or minimize radiation exposure.

Re:Cancer... (1)

Anonymous Coward | more than 2 years ago | (#39632169)

Most medical (film) X-rays expose the film using light. The machine has a thick, X-ray absorbent, plate that fluoresces (light) when exposed to X-rays and the film is more sensitive to light rather than X-rays. The result is that a lower dose of radiation is needed.

This, presumably, also applies to the full-head (dental) X-rays.

In bitewings, the film is exposed directly to the radiation. Film is not very sensitive to X-rays therefore the required dose is higher.

I'm so sorry! (-1)

Anonymous Coward | more than 2 years ago | (#39630703)

I'm sorry, but I have to get this off my chest after all these years. I was...the one who gave Steve Jobs AIDS. I have been HIV positive for nearly a decade and I knew I shouldn't have had sex with him in the bathhouse that night, but when he started stroking my shaft and fingering my prostate I lost all sense of reason. I told him we should use a condom 'just in case' but he demanded that I fuck him bareback and I couldn't help but to orgasm in his asshole. A few months later was when he first started having health issues and I've felt bad ever since.

OH BOY (0)

DC2088 (2343764) | more than 2 years ago | (#39630709)

HERE WE GO Line the antivax folks up to half-read this summary.

Re:OH BOY (0)

drinkypoo (153816) | more than 2 years ago | (#39630855)

HERE WE GO Line up the trolls at your mom.

Re:OH BOY (1)

PenisLands (930247) | more than 2 years ago | (#39631123)

Hah hah hah, you're a real cocker now. I'm impressed. You're beginning to get the hang of things. If you keep this up, I might change you from 'enemy' to 'friend' or whatever they call it.

PENIS FOREVER!!! !!! !!!

inhaling air (0)

Anonymous Coward | more than 2 years ago | (#39630721)

inhaling air linked to lung and pancreatic tumors (blablabla, poppycock)

Finally (2)

medv4380 (1604309) | more than 2 years ago | (#39630731)

A valid reason to avoid the dentist

Between that and Mercury thats "locked" in filling (0)

Anonymous Coward | more than 2 years ago | (#39630743)

Time for a review of dental practices?

How many GRAMS of Hg are put into fillings and how much erodes over time?

Will eating acidic foods be linked to releasing Hg and then causing neuro disorders?

Re:Between that and Mercury thats "locked" in fill (3)

MountainLogic (92466) | more than 2 years ago | (#39631141)

While we take dentistry for granted, an infection driven by a bad tooth used to be a common cause of death. Bad teeth are still a common driver to the ER for many uninsured. Remember Tom Hanks knocking his bad tooth out with an ice skate and a rock on the island? Not going to the dentist for your lifetime has a greater chance of killing you than a rare cancer from a few low dose x-rays. That said, it never hurts to make sure you dentist is using modern low dose digital equipment and not taking any unnecessary images.

re: taking dentistry for granted (4, Interesting)

King_TJ (85913) | more than 2 years ago | (#39631659)

I'm not trying to marginalize your point, but at the same time? It seems to me that dentistry is one of the areas of medicine with the least amount of oversight or "checks and balances" to ensure patients are getting what they pay for.

For example, I went to a dentist as a teenager to have an impacted wisdom tooth extracted. The oral surgeon recommended that I have "all 4 wisdom teeth pulled at the same time, since there was a good chance the others weren't all going to come in properly anyway - and it would be less painful if I only went through one extraction". I went with his recommendation, only to find that a couple years later, I had cavities in the back of a couple of my teeth, where they faced those wisdom teeth. Apparently, their enamel was damaged in the tooth extraction process, causing them to get cavities. So then I had those filled, but I remembered thinking the whole process was a bit questionable at the time, because he had a young dental assistant working with him, who he asked to mix up the amalgam filling material for him. I remember him looking at it and questioning her about whether she mixed something up enough because it didn't look quite right, stirring it around a bit in the container she was holding, and ultimately going ahead and using it on my teeth. Well, fast forward a couple more years, and I start having a bad toothache. I go to a dentist (totally different place!) and I'm informed that tooth has a big hole in the back of it (where the filling material had obviously fallen out) and the tooth isn't even salvageable anymore!

I look at all of this and have to wonder if I would have been better off if I had only opted to have the bare minimum work done in the beginning? Seems like all these dentists did was create more problems for other dentists to correct, at my expense!

And my daughter is further making me question some of these dentists.... When she was 8 years old, the pediatric dentist commented that "he saw something on the x-rays that concerned him" and "she might need some dental work, but we'll see". The next time she came in for a checkup, he wanted to schedule an expensive dental surgery procedure for her because he claimed a tooth wasn't going to come in right, etc. etc. Well, I didn't have the money so I kept putting it off.... I did send her to the next scheduled checkup though, where they declared "She doesn't need that surgery after all!" (Really?! WTF?!)

Oh, and then there's my younger brother, who had all kinds of dental problems after his dentist screwed up a procedure -- but of course, denies any of it was his doing.

It's a revenue thing. (1)

Anonymous Coward | more than 2 years ago | (#39631661)

X-Rays are overused by dentists these days - more of a revenue stream than for diagnosis.

For example, I had a filling fall out - I even had the gum that pulled it. Nope. Gotta have an x-ray. Dentist looks at it and exclaims, "Yep, the filling fell out!"

No shit. You need a DMD or DDS to known that?

Over the years, I've had a shit load of dental problems - like necrotic teeth. Not a single one was ever predicted or found with an x-ray. None. And yet, they insist to the point of refusing to do business with you if you refuse.

Many years ago, I had a dentist that very rarely took x-rays. If a filling fell out, he looked with a mirror. I once had horrible pain. He first ordered x-rays and after looking, he canceled. It was a horrible gum infection due to my wisdom teeth breaking though.

On some procedures the insurance company will demand to see the x-ray. But the keyword is "some".

It's all about revenue.

Re:Between that and Mercury thats "locked" in fill (2)

Defenestrar (1773808) | more than 2 years ago | (#39631167)

And of course the most important question of them all: do Anonymous Cowards know the difference between amalgamated metals and organometallic compounds?

Only second to the question of how hard can it be to find this stuff? [lsro.org]

Numerous studies have demonstrated a positive correlation between the number of dental amalgam restorations or surfaces and urine mercury concentrations in non-occupationally exposed individuals. Mean urine mercury concentrations (HgU) were less than 2 g Hg/L in most surveys of the general population that were published since the beginning of 1996. Furthermore, approximately 95% of the study participants had HgU at or below the pre-1996 WHO estimate of approximately 4-5 g Hg/L.

...

Current occupational exposure guidelines recommend that the HgU of workers not exceed the Biological Exposure Index of 35 g Hg/L

Re:Between that and Mercury thats "locked" in fill (1)

GameboyRMH (1153867) | more than 2 years ago | (#39631413)

Even if all the mercury leaks out of a filling over the course of a few days it won't harm you. It's not good for you, but you'll be fine.

And it took this long to "make the connection"? (0, Troll)

dryriver (1010635) | more than 2 years ago | (#39630745)

Everybody with half a brain has known for decades that radiation, whether it comes from an X-Ray or the current mess that is the Fukushima NPlant, is dangerous, and very much capable of causing cancer. So how on earth did it take THIS LONG for the link between dental X-Rays and brain tumours to be made? I don't want to get all conspiratorial, but it seems to take 3 - 5 decades each time, for something involving radiation actually being linked to cancer. For example, after over 2 decades of rumors and talk about it, we still don't know with any degree of certainty whether cellphones/mobilephones do or don't cause cancer. Given the overall time trend established, we'll probably know for sure, say, 2 - 3 decades from now, when its too late for any of us to stop using a mobile phone.

Re:And it took this long to "make the connection"? (5, Informative)

houstonbofh (602064) | more than 2 years ago | (#39630839)

Mobile phones do not release Ionizing Radiation. They release Radio Waves. These are different things. Really... You can take off your tin foil hat to make calls again.

Re:And it took this long to "make the connection"? (0)

Anonymous Coward | more than 2 years ago | (#39631129)

They are not "very different things". X-rays are high frequency photons, "Radio Waves" [sic] are lower frequency photons. How did this shit get modded +5? "Radio Waves" are just as ionizing when you are in the near field of the antenna. But then, I hardly expect a basic knowledge of physics from the software crowd.

Re:And it took this long to "make the connection"? (0)

Anonymous Coward | more than 2 years ago | (#39631279)

But then, I hardly expect a basic knowledge of physics from the software crowd.

That's ok, based on your statement above we hardly expect basic knowledge of physics OR biology from the tinfoil hat crowd.

Re:And it took this long to "make the connection"? (4, Insightful)

Rhacman (1528815) | more than 2 years ago | (#39631381)

Because it is true. The term "ionizing radiation" is not just causal lingo, it is very specifically defined as radiation that is capable of liberating an electron from an atom thus producing an ion. This is not the case for lower frequency electromagnetic radiation such as that produced by mobile phones. Any potential health effects resulting from mobile phone use would have to be due to an entirely different mechanism.

Re:And it took this long to "make the connection"? (3, Informative)

FrootLoops (1817694) | more than 2 years ago | (#39631627)

According to the EPA [epa.gov] (and other places), radio waves are firmly in the non-ionizing range whereas x-rays are definitely in the ionizing range. You'll have to provide some evidence that near field effects increase radio wave energy sufficiently to shift the radiation into the ionizing range with cell phones; I couldn't find any, and it's a strong claim to make. Considering the lack of unambiguous cell phone/cancer links I doubt such evidence exists.

Re:And it took this long to "make the connection"? (0)

Anonymous Coward | more than 2 years ago | (#39631899)

"According to the EPA [epa.gov] (and other places), radio waves are firmly in the non-ionizing range"

Yes, as long as you're more than one wavelength away from the antenna. In the near field, you will be ionized. It doesn't take much. A 4W handheld CB at 27MHz will light up a neon tube when you bring the antenna close to the bulb.

You are free to stand close to a short-wave 1KW transmitter's antenna if you believe your theory.

Re:And it took this long to "make the connection"? (0)

Anonymous Coward | more than 2 years ago | (#39631631)

But then, I hardly expect a basic knowledge of physics from the software crowd.

Yeah. Nice goin', Einstein!

Re:And it took this long to "make the connection"? (5, Insightful)

DeadCatX2 (950953) | more than 2 years ago | (#39631873)

The shit got modded +5 because...lo and behold...RF from a mobile phone is non-ionizing radiation. I agree that the term "radio waves" could have been better. But it would take tens of thousands of RF photons simultaneously striking the same exact electron at the same exact time to give it enough energy to break free from the atomic bond it has formed. It only takes one photon from an x-ray to do the same.

Go ahead. Do the math. Look up the energy it takes to ionize an atomic bond. Calculate the energy in an RF photon at 2.4 GHz. Calculate the energy in a photon of an dental x-ray (not sure what frequency they use). And then marvel at the four orders of magnitude between the two. I did this once, and maybe I should have saved a copy of the results so that I could paste it into the discussion every time some tin foil hatter thinks that 2.4 GHz "radiation" will give you cancer.

The primary mode of action for RF energy on biological tissue is in the form of heating. Just like your microwave. The electric field causes the dipole water molecules to rattle around, and the increased friction results in heat.

In fact, if you get an MRI, they make sure that for example your thighs are not touching each other. Because if they are, your flesh forms a loop antenna that can pick up the RF energy in the magnet room...which will cause localized heating and burns.

http://www.mrisafety.com/safety_article.asp?subject=17 [mrisafety.com]

"-Prepare the patient for the MR procedure by using insulation material (i.e., appropriate padding) to prevent skin-to-skin contact points and the formation of “closed-loops” from touching body parts."

Re:And it took this long to "make the connection"? (-1)

Anonymous Coward | more than 2 years ago | (#39631295)

Mobile phones do not release Ionizing Radiation. They release Radio Waves. These are different things. Really... You can take off your tin foil hat to make calls again.

Tell that to the late Todd Witskin's wife and the family who survives him.

Re:And it took this long to "make the connection"? (3, Informative)

digitig (1056110) | more than 2 years ago | (#39632013)

I think you will find that people died of brain tumours even before the mobile phone was invented. What was your point?

Re:And it took this long to "make the connection"? (1, Funny)

Anonymous Coward | more than 2 years ago | (#39630883)

Everybody with half a brain probably had too many x-rays.

Re:And it took this long to "make the connection"? (0)

Anonymous Coward | more than 2 years ago | (#39631161)

Everybody with half a brain have 50% less chances to get a brain tumor.

Re:And it took this long to "make the connection"? (4, Interesting)

DrData99 (916924) | more than 2 years ago | (#39630897)

Well, I know that it is uncommon on /. to actually RTFA, but:
>>
The lack of association with full-mouth X-rays led one expert to question the connection.

"They found a small risk (from) a pair of bitewings, but not a full mouth series, which is multiple bitewings. That inconsistency is impossible to understand to me," said Dr. Alan Lurie, president of the American Academy of Oral and Maxillofacial Radiology.
>>
So a small risk (increase from 15/10,000 to 22/10,000) caused by a pair of bitewings disappears when you do more?

I don't think so...

Re:And it took this long to "make the connection"? (1)

medv4380 (1604309) | more than 2 years ago | (#39631229)

If that's the case then I'd like to see their sample size for full mouth x-rays. I'd bet it's smaller than the sample size for the partial/single bitwing and that could be the source of the vanishing connection. Basic statistics, if a known correlation exists, and you didn't find it in your particular sample check your sample size first. Throwing out the correlation because the smaller sample doesn't show what the larger sample does sounds a bit foolish, and if done that way would result in no correlation ever being found in anything.

Re:And it took this long to "make the connection"? (2)

CatsupBoy (825578) | more than 2 years ago | (#39631361)

If that's the case then I'd like to see their sample size for full mouth x-rays. I'd bet it's smaller than the sample size for the partial/single bitwing and that could be the source of the vanishing connection. Basic statistics, if a known correlation exists, and you didn't find it in your particular sample check your sample size first. Throwing out the correlation because the smaller sample doesn't show what the larger sample does sounds a bit foolish, and if done that way would result in no correlation ever being found in anything.

Or the sample size for full mouth was larger and a better representation of the norm. Or both were the same just too small to draw a conclusion from.

Either way Lurie is correct in asserting that this type of inconsistency results in an inconclusive study.

Re:And it took this long to "make the connection"? (2)

mspohr (589790) | more than 2 years ago | (#39632205)

Since the reports of "dental x-rays" were based on patient's memory and not on actual dental records, it is likely that there is some error here. Many people probably don't remember or don't know the difference between bitewings and full mouth x-rays. They probably only remember that they had some dental x-rays. I wouldn't put too much emphasis on the difference between the two.

Re:And it took this long to "make the connection"? (2)

budgenator (254554) | more than 2 years ago | (#39631939)

Yeah ironic isn't it, the type of dental radiographs that people who are paranoid of radiation exposure are most likely to insist on, is shown in a Cohort Study [wikipedia.org] , which are infamous for finding false associations, to be the one more likely to cause brain cancer! Yet a FMX, Full Mouth X-ray which includes at least two Bitewings doesn't. My Magic Eight Ball says "People who show up at the Dentist's office with an acute symptomatic tooth that is leaking bacterial toxins into their blood streams are also;
  More likely to get Menigiomas,
  More likely to need an exquisitely painful root canal,
  More likely to have a heart attack,
  More likely to get type 2 diabetes,
Than people how receive routine dental care.

Re:And it took this long to "make the connection"? (1)

Zibodiz (2160038) | more than 2 years ago | (#39632077)

Full mouth X-rays (4 bitewings and a Pan [wrap around] or 4 bitewings and 14 PAs) are taken once every 3-5 years, bitewings are taken every 6-12 months. That would seem like a valid difference to me. However it didn't say in the article, so perhaps they took that into consideration.

Re:And it took this long to "make the connection"? (1)

Microlith (54737) | more than 2 years ago | (#39630903)

Hey look, a stupid, panicky post made in repsonse to "brain tumor" and "radiation" with not a shred of accuracy.

Everybody with half a brain has known for decades that radiation, whether it comes from an X-Ray or the current mess that is the Fukushima NPlant, is dangerous, and very much capable of causing cancer.

But that doesn't make it obvious that a dental x-ray would be a source of such mutations. Like all x-rays they are carefully dosed and focused on a narrow region.

don't want to get all conspiratorial, but it seems to take 3 - 5 decades each time, for something involving radiation actually being linked to cancer.

Yeah, it takes a LONG time for studies to show any sort of trend or linkage. Of course, if we had read the article:

And regardless of the age when the bitewings were taken, those who had them yearly or more frequently were at between 40 percent and 90 percent higher risk at all ages to be diagnosed with a brain tumor.

To put that in perspective, Dr. Paul Pharoah, a cancer researcher at the University of Cambridge said in a statement the results would mean an increase in lifetime risk of intracranial meningioma in the U.K. from 15 out of every 10,000 people to 22 in 10,000 people.

So, not that huge an increase. And it can be mediated by more carefully controlling how often and when such x-rays are performed.

For example, after over 2 decades of rumors and talk about it, we still don't know with any degree of certainty whether cellphones/mobilephones do or don't cause cancer. Given the overall time trend established, we'll probably know for sure, say, 2 - 3 decades from now, when its too late for any of us to stop using a mobile phone.

And this is where the stupid arises. You see, had you ever bothered to stop and learn about electromagnetic radiation, you'd know that cell phones don't emit ionizing radiation, which is what x-rays are. And non-ionizing radiation doesn't have enough energy to cause cancer. To heat you up a tiny fraction of a percent, yes, but not damage the DNA of your cells.

Re:And it took this long to "make the connection"? (1)

NotQuiteReal (608241) | more than 2 years ago | (#39631051)

So, not that huge an increase.

Actually 46% is a huge increase.

Re:And it took this long to "make the connection"? (5, Informative)

drerwk (695572) | more than 2 years ago | (#39631565)

So, not that huge an increase. Actually 46% is a huge increase.

They never seem to show the error bars. We are looking at a sample of 15. Not knowing anything else, one might assume Poisson statistics in which case the 1 sigma error is 1/sqrt(sample), so about 25%.
This means that 66% of the time, if one were to run the exact same test, one would get results that varied by plus or minus 4 events. The difference between a sample of 15 and a sample of 21 can be expected about half the time.
It really takes the urgency out of - OMG a factor of 46%.
http://en.wikipedia.org/wiki/Poisson_distribution [wikipedia.org] .

Re:And it took this long to "make the connection"? (1)

TheRaven64 (641858) | more than 2 years ago | (#39631187)

But that doesn't make it obvious that a dental x-ray would be a source of such mutations. Like all x-rays they are carefully dosed and focused on a narrow region.

I've had a couple of dental X-rays. Both times I was asked if I'd had any kind of head X-ray within the last year. The last one was almost a decade ago, and even then they were very hesitant to X-ray anyone more than once every few years. Saying that there is an increased risk for people who have 'one or more' dental X-rays per year is repeating something that dentists have apparently known for a very long time. Quantifying that risk may be news, but the existence of it certainly isn't.

Re:And it took this long to "make the connection"? (1)

Ogi_UnixNut (916982) | more than 2 years ago | (#39630957)

IMO That's because it takes a few decades for the "new adopters" of a technology to get old enough to provide enough data for how damaging these things are to us. We've already studied and solved things that harm us in the short term, but things like whether something causes a higher incidence of cancer requires you to
a) Get cancer
b) Lots of other people from your generation to get cancer (both those who used the technology heavily or none/a little)

Then you can look at cancer types, where they start, how aggressive they are, etc... and compare between the groups, from where a link can be hypothesized.

Basically we're being guinea pigs, just like the older generations were guinea pigs for asbestos use, and all sorts of other things that we know now are bad (hell, there was a time when people thought being exposed to radiation was a good thing, people would deliberately go out and get irradiated for good health).

The only way to avoid this is to basically only use old technology. The stuff tested out by the previous generation we got an idea about already (but more research is needed), so best go back a few generations.

Most people on this planet however, do not want to go back to a life 100 years ago, so in exchange for all the fancy new tech and goodies (like Wifi for example), we expose ourselves to the unknown, including potentially health damaging stuff.

look on the bright side (1)

circletimessquare (444983) | more than 2 years ago | (#39630975)

it only affects those people constant babbling loudly in quiet public places about their boyfriend's parents, their kid's rash, or their awesome trip to the city, because they have the cell phone constantly stuck to their ear

a mobile app user like myself, i just keep my cell phone at my waist, so my brain is fine. it only means i'm going to be sterile and leave no offspring

it will be quieter world, whatever type of mobile user you are

Re:And it took this long to "make the connection"? (0)

Anonymous Coward | more than 2 years ago | (#39631001)

Fukushima == nuclear radiation
x-ray == electromagnetic radiation

They use the same word, but they're not at all the same thing.

Re:And it took this long to "make the connection"? (1)

lloydchristmas759 (1105487) | more than 2 years ago | (#39631301)

Wrong. Gamma rays are also electromagnetic waves, but with a higher frequency than X rays. It is true, however, that alpha and beta rays are made of electrons/protons, which is different.

From what we know today, the only thing that matters for cancer risk is whether the radiation is ionizing or not. If it is (X rays, gamma rays, alpha and beta particles, ultraviolet rays), it CAN cause cancer. If it isn't (microwave, visible light, infrared, everything below), it CANNOT cause cancer (as far as we know). This is why it is unlikely that mobile phones can cause cancer (they use microwaves).

Re:And it took this long to "make the connection"? (4, Insightful)

dr.Flake (601029) | more than 2 years ago | (#39631117)

Supposing this is true, it took this long because everybody thought that dental X-ray was harmless.
(tumor growth in less than 1:4.000.000 images, regardless of the type of tumor.)

Dental X-ray uses less than 0.01 mSv per image.

You absorb 200 times this amount every year, year in, year out. all your life. And if you live in a place with higher background radiation, this number goes up quickly.

So it is hard to prove these tumours are caused by the exams.
Lets wait and see what comes out of this.

Usually these kind of studies have some form of bias thats not adequately corrected for.

Re:And it took this long to "make the connection"? (0)

Anonymous Coward | more than 2 years ago | (#39631363)

>You absorb 200 times this amount every year, year in, year out. all your life.

Another way of looking at this is that an xray concentrates over a day of normal radiation exposure into a fraction of a second of intense exposure. It doesn't sound so minor put that way.

Re:And it took this long to "make the connection"? (0)

Anonymous Coward | more than 2 years ago | (#39631121)

If you had half a brain, you'd realize that mobile phone's don't cause cancer. How could they? They don't emit any ionizing radiation. It is basic chemistry, nothing with a wavelength longer than UV can ionize a molecule. No ionization means no DNA damage and no cancer.

Additionally, people are not going to stop using a mobile phone even if it did raise your chances of cancer a little bit. Mobile phones are very useful and everything causes cancer. I am not going to make drastic lifestyle choices to change my odds of cancer from 46% to 42% or something like that. Besides, in 20,30, 40 years we'll have much better treatments for cancer.

It takes decades of research because you need a lot of data over a long period of time to pick up tiny increases in cancer in a statistically meaningful way. You are talking about maybe a couple percent in absolute probabilities, or a few percent in relative probabilities.

Re:And it took this long to "make the connection"? (0, Interesting)

Anonymous Coward | more than 2 years ago | (#39631227)

"It is basic chemistry, nothing with a wavelength longer than UV can ionize a molecule."

In the far field. In the near field, the electric field is very high. You can light up a straight old neon tube with a 27MHz walkie talkie.

Re:And it took this long to "make the connection"? (1)

DerekLyons (302214) | more than 2 years ago | (#39631169)

I don't want to get all conspiratorial, but it seems to take 3 - 5 decades each time, for something involving radiation actually being linked to cancer.

Because cancers don't appear immediately after exposure - sometimes it takes decades for the cancers to appear. Then, once cancer does appear, you have to wait until enough of those cancers appear to have a valid statistical base. Then you have to work through all the potential causes to isolate the prime cause... And that's all made more difficult when the type of cancer is rare, as this type is. Worse yet, a large percentage of this type never result in gross symptoms - they're only discovered during autopsy.
 
Science takes time. Real life isn't a TV show where major medical breakthroughs occur by the 2nd commercial break.

Re:And it took this long to "make the connection"? (1)

SebZero (1051264) | more than 2 years ago | (#39631217)

Honestly? The reason is science

It's all well and good for you to go "RAAAAR COMMON SENSE" but it's incredibly difficult to prove anything like this in real people who live different lives in different places doing different things, because even if all of the above were the same it would take 20+ years. Completely ignoring the money.

not sure (2, Interesting)

Anonymous Coward | more than 2 years ago | (#39630755)

I'm a dental student, and I have been taught that - with modern equipment - exposure to radiation from 2 bitewings is about the same as half a day of ski holiday. You really need to take a lot x-rays to expose patients to significant more ionizing radiation than they receive from nature itself.

Re:not sure (1)

Anrego (830717) | more than 2 years ago | (#39630895)

Along these lines, my dentist once told me that the lead apron they have you wear is more for patients peace of mind then necessity.

Re:not sure (2)

Flammon (4726) | more than 2 years ago | (#39631887)

Ya, and that's why they leave the room when taking the x-ray.

Re:not sure (0)

Anonymous Coward | more than 2 years ago | (#39630913)

Uh huh, and the people telling you that are the people selling you the xray equipment. There is no reason for dentists to take xrays unless there is a major issue. Except to make some extra bucks.

Re:not sure (0)

Anonymous Coward | more than 2 years ago | (#39631079)

Taking x-rays is about finding problems you wouldn't have noticed otherwise. About finding small holes in your teeth before they become big holes and you needing a root canal treatment. Or things happening inside the jaws, that sort of stuff. Not about making some extra bucks. Well, it is if you take x-rays every 6 months or so without a good reason. But normally nobody does that.

Re:not sure (0)

Anonymous Coward | more than 2 years ago | (#39630939)

Yeah, a half day of skiing radiation put into a 1" focal point all in about 4 milliseconds. Sure, that won't cause any problems.

Re:not sure (1)

Skidborg (1585365) | more than 2 years ago | (#39630949)

Key word being "modern equipment". It's not like most dental offices are just thrilled to discard their insanely expensive, decades-old X-ray machine and buy a brand new insanely expensive machine that does the same thing.

Re:not sure (1)

MountainLogic (92466) | more than 2 years ago | (#39630969)

Holy X-Ray batman. I live in a ski area!!!!! I'm a goner. Nice knowing you all.

Re:not sure (0)

Anonymous Coward | more than 2 years ago | (#39632085)

Well, this would definitely depend on which ski area. If there is an abundance of expert slopes, excellent snow conditions, and first class resorts, then yes, you are a goner. OTOH, if the skiing sucks, you are also most definitely a goner, but mostly because you will likely die in a drinking accident due to the snow being so awful.

Moral: move to a hermetically sealed plastic bubble in Iowa. Avoid sharp objects, political demonstrations, and other risky activities.

Re:not sure (5, Insightful)

Remus Shepherd (32833) | more than 2 years ago | (#39631247)

I'm a dental student, and I have been taught that - with modern equipment - exposure to radiation from 2 bitewings is about the same as half a day of ski holiday.

These comparisons are always misleading, because they ignore the density of the radiation received. Radiation from half a day of ski holiday is diffused over your entire body. The radiation from bite wing X-rays is concentrated on your teeth and skull. The concentration matters.

Let's use a better analogy. The energy at the focal point of a magnifying glass might be one-hundredth the amount of energy you get from standing out in the sunshine. But because that energy is concentrated into a small point, it will burn your skin.

We survive nature not because it isn't powerful, but because its power is spread out. That power gets dangerous when mankind focuses and purifies it.

Re:not sure (1)

malakai (136531) | more than 2 years ago | (#39631517)

Point is, it's as likely that the film you bite down on and the plastic it's covered in turns out to be carcinogenic. We're talking a very small amount of radiation here.

Re:not sure (0)

Anonymous Coward | more than 2 years ago | (#39631357)

with modern equipment - exposure to radiation from 2 bitewings is about the same as half a day of ski holiday.

What the hell does that even mean? (Insert your favorite joke about libraries of congress per furlong here.)

Re:not sure (1)

FrootLoops (1817694) | more than 2 years ago | (#39632145)

The article sort of touches on this:

Lurie also echoed Claus' caution that radiation levels from dental X-rays when some of the participants were younger was much greater than is used now.

The result may be different if everyone had used today's equipment the whole time.

I've often wondered... (3, Interesting)

Daetrin (576516) | more than 2 years ago | (#39630761)

They give you this big heavy blanket (lined with lead? I dunno) to lay across your body when they do the x-ray. They seem to think it's important to block off the areas they're not actually imaging. So why don't they give you something similar to lay across the top half of your face and head? Obviously it wouldn't stop everything, but you'd think it would help at least a little.

Re:I've often wondered... (3, Informative)

houstonbofh (602064) | more than 2 years ago | (#39630859)

Because it is bouncing off your teeth and jaw so the cap would keep it in.

Re:I've often wondered... (0)

Daetrin (576516) | more than 2 years ago | (#39631009)

Isn't that answer a little simplistic? First, do those liners actually reflect the photons? Or do they absorb them?

Second, if you've got a relatively flat layer across the top of your face/head, then the only particles that could be bounced off the sheet are the ones that bounced back from your jaw at somewhere between a 180 and 225 degree angle (speaking very approximately.) I have no idea what the scatter pattern is like, but that would obviously only be a fraction of the photons that actually get reflected. The fact that they bother putting a lead apron on your body seems to indicate they feel there's some reasonable amount of imperfectly focused particles you should be expecting from your front, and i would expect that amount to be higher closer to where the beam is actually supposed to be focused.

Re:I've often wondered... (1)

gstrickler (920733) | more than 2 years ago | (#39631495)

Lead doesn't reflect radiation, it absorbs it. But that's irrelevant because "bouncing off your teeth and jaw" is equally flawed. X-Rays and other forms of ionizing radiation don't "bounce off" surfaces, it will either pass through, be absorbed, or trigger another particle to be emitted. There are 3 types of radiation that may be emitted, alpha, beta, and gamma. Alpha and beta will only penetrate a few millimeters of solid/liquid matter such as skin, muscle, etc so those won't make it back out of the body. Gamma (and the x-rays themselves) are best shielded by dense materials such as lead. However, putting a shield over the patient's head would only protect other people in the room, not the patient, because any such radiation would coming OUT of the patient's head. The only protection the patient would gain from wearing a lead cap is from any stray x-rays from the machine, and if the machine is emitting any notable amount of stray x-rays, it needs repair or replacement.

There is also neutron radiation, but that's also not a concern because: A) it's not common and not likely to be caused by an x-ray. B) is heavily moderated by water, so may not make it out of the body. C) passes through most materials, including thin layers of lead, so it's unlikely that any neutrons emitted would be stopped by a wearable shield.

Re:I've often wondered... (1)

Anrego (830717) | more than 2 years ago | (#39630955)

My dentist once told me that the apron is more for patient peace of mind then any practical purpose these days. Given the nature of how the x-rays are delivered, it would seem a useless measure (hint: they point the thing at your head...).

CMOS imaging? (3, Interesting)

AmonRa1979 (797618) | more than 2 years ago | (#39630771)

Any word on whether there was a decline in this type of tumor when CMOS x-ray imaging started being used in dentistry? Using CMOS rather than film supposedly requires less exposure time or less x-ray intensity in order to obtain an image comparable to film. I see the article does comment on the decreased intensity of x-ray source now as compared to a decade or so ago, but unless they couldn't readily identify this type of tumor back then, then I would expect to have seen a decline in this type of tumor as well.

Re:CMOS imaging? (1)

Guppy (12314) | more than 2 years ago | (#39631921)

Although the sensitivies for film and sensors have been improving, dental head CTs (which are much higher dose) have become increasingly common. While dental CTs are intended for special situations involving complex procedures, I've head of them being used in routine care as well, and it'd be interesting to know if it off-sets doage reductions elsewhere.

Wow I'm surprised! (1)

Mass Overkiller (1999306) | more than 2 years ago | (#39630779)

Jeeze, taking X-rays of your mouth might give you brain caner, that's a shocker. I wonder if people will also get cancer from the TSA scanners in 20 years? Think the DHS will actually perform a study to see what the long-term health risks are? Doubt it, not if there's money to be ma^H^H^H terrorists to be found. BTW the article summary is based on what people "remember", as in it's not necessairly a scientific study. They asked people who got brain cancer if they ever had dental x-rays. FTA "results are based on people who were likely exposed to higher levels of radiation during dental X-rays than most are today." Nonetheless it does show a corelation but not a scientific link nor causasion.

Re:Wow I'm surprised! (0)

Mass Overkiller (1999306) | more than 2 years ago | (#39630793)

Heh my first slashdot first post woot!

But But But.... (0)

RivenAleem (1590553) | more than 2 years ago | (#39630781)

Mobile phones, antennas and powerlines!

Re:But But But.... (2)

3c5x9cfg (41606) | more than 2 years ago | (#39630845)

are sources of non-ionizing radiation.

Re:But But But.... (1)

medv4380 (1604309) | more than 2 years ago | (#39630877)

Not worried until the X-ray powered cell phone is released.

Some good, some bad. (1)

Anonymous Coward | more than 2 years ago | (#39630807)

On the one hand, is this something to be worried about? It depends. The incidence rate is around 15 in 10000 in the UK so your lifetime risk goes up to 22 in 10000 if you have them yearly. Don't be fooled by the sensationalist percentages.

On the other, the study is a bit weird in that it doesn't mention correlation with full mouth x-rays, only bitewings. There's additional haziness about the dosages people used to get; the effect is stronger when people had x-rays as children, but we suspect the dosage was higher back then.

"They found a small risk (from) a pair of bitewings, but not a full mouth series, which is multiple bitewings. That inconsistency is impossible to understand to me," said Dr. Alan Lurie, president of the American Academy of Oral and Maxillofacial Radiology.

So the message is: make sure you really understand why you need an x-ray before you get one, but don't worry too much if it's once every few years. Also, don't irradiate your kids.

Well at least... (2)

Sfing_ter (99478) | more than 2 years ago | (#39630861)

Well, at least our friends in the UK won't have to worry about this... :P

What are dental X-rays for, anyways? (1)

CubicleZombie (2590497) | more than 2 years ago | (#39630865)

What are they looking for? I have them every couple of years and the dentist always says that everything's normal. When I did have a cavity, it was found by that iron hook, not an x-ray. So what's the point?

Re:What are dental X-rays for, anyways? (1)

SydShamino (547793) | more than 2 years ago | (#39630911)

I think they identify problems below the gumline, or some problems inside the teeth. I presume they could find a cancerous mass in a jaw sooner and save some lives too. Perhaps when smoking/chewing was more prevalent that was a good service, but the odds of a modern nonsmoker getting jaw cancer are likely quite low.

Re:What are dental X-rays for, anyways? (1)

TeknoHog (164938) | more than 2 years ago | (#39631205)

I presume they could find a cancerous mass in a jaw sooner and save some lives too. Perhaps when smoking/chewing was more prevalent that was a good service, but the odds of a modern nonsmoker getting jaw cancer are likely quite low.

Seems like a nice business plan:
1. Take dental X-rays
2. Which cause jaw cancer
3. Which can only be found using dental X-rays
4. Profit!
5. GOTO 1

Re:What are dental X-rays for, anyways? (1)

mx+b (2078162) | more than 2 years ago | (#39630921)

Wisdom teeth for one. One of mine never broke thru the gum, so my dentist x-rayed me to see where it was because I had such awful jaw pains. It was sideways! Literally sideways pressing into the tooth next to it. I obviously had oral surgery not long after that. I wish I had a picture of that xray, it really amused me.

Re:What are dental X-rays for, anyways? (0)

Anonymous Coward | more than 2 years ago | (#39631323)

All four of mine were like that. I wish I saved a picture, too. And yeah, with the gums covering them, I'm not sure how the dentist would see what was wrong without the X-ray.

But I don't get one every year just for the hell of it. Who does that?

Re:What are dental X-rays for, anyways? (2)

Qzukk (229616) | more than 2 years ago | (#39630943)

So what's the point?

Judging from my credit card history, dental x-rays are for around $150.

Doctors aren't the only ones getting paid big bucks for doing so many so-called "defensive" tests.

Re:What are dental X-rays for, anyways? (0)

Anonymous Coward | more than 2 years ago | (#39630983)

Their purpose is to increase the amount of profit dentists extract from your wallet.

Bunch of reasons: (1)

sirwired (27582) | more than 2 years ago | (#39631055)

- Cavities between the teeth that cannot be found via the probe. If they are caught early, they can be easily treated. If you wait until they CAN be found by the probe, you risk a root canal, or worse.
- The dentist is looking for bone recession indicating gum problems
- Abscesses under the gumline.

Re:What are dental X-rays for, anyways? (1)

dmbasso (1052166) | more than 2 years ago | (#39631441)

Searching for cavities is the only thing dentists do? I bet you can be more imaginative if you try a little bit more.

Re:What are dental X-rays for, anyways? (0)

Anonymous Coward | more than 2 years ago | (#39631703)

Because many dental plans cover them for free every X months, and the dental place can than make that much money every X months.

I think there is no reason to do them on an adult more often than once a year, and I refuse them accordingly.

(But seriously, I've changed jobs often, and notice my dentist will push every procedure on me that is 100% covered by my dental plan at the time.)

Flawed Study (5, Informative)

blahbooboo (839709) | more than 2 years ago | (#39630929)

This is a very flawed study that doesn't account for many things including a) It's based on patients "memories" of when they got x-rays and not actual dates b) Doesn't account for the dramatic reduction in amount of rays needed for the images in the last 20-30 years.

Proof? Check this far better article http://articles.boston.com/2012-04-10/metro/31313701_1_x-rays-tumor-risk-radiation-exposure [boston.com]

Re:Flawed Study (1)

djrobxx (1095215) | more than 2 years ago | (#39631245)

Most people go to the dentist regularly. I can easily tell you that for the last 10 years, once a year, I've gotten my smaller x-ray panels. This month I got full panel. The precise dates probably don't have much bearing on the result.

Re:Flawed Study (0)

Anonymous Coward | more than 2 years ago | (#39631737)

Fear Mongering is one of the main pastimes of the mass media.

Most scientific papers are wrong. That's a fact. Its OK though - thats what science is - getting it wrong most of the time, so when we get something right, we learn and move forward.

That said, there is a huge amount of incentive to have a paper make it to 'general news' or 'slashdot'. If you do, you will certainly be funded for the next study, and things like promotions happen easier. The pressure is intense.

So here is a paper that basically says: We took a lot of data, then looked at dental X-Rays vs one kind of cancer and found a correlation. But another kind of more intense X-Rays did not cause a correlation. The results make no sense, but are sensational if reported in the following way..

There are also studies that show that radiation in doses much much bigger than these resulted in lower rates of cancer - but those people don't get re-funded as often! Look up hormesis.

Small study? CT of brain?? (1)

Anonymous Coward | more than 2 years ago | (#39630981)

Seems a little "small" and cherry-picked to prove causation.

For starters, there is currently no evidence that CT scans cause cancer. But a CT of the brain - which is now done routinely on head injury patients entering emergency rooms, exposes you to much, much higher radiation levels than any static x-ray at dental office. I'm talking at least 1000x or more. 10mSv for head CT?? (someone check)

So if dental xray gets you brain tumors, then brain CT caused tumors should light up on the map like lightbulbs in the dark.

You get more radiation from those airport scanners (xrays), than the dental xrays.

Re:Small study? CT of brain?? (0)

Anonymous Coward | more than 2 years ago | (#39631065)

You may also want to add from FTA,

There was no association between full-mouth X-rays and the tumors, although the authors note they saw a trend similar to that seen for the bitewing X-rays.

The lack of association with full-mouth X-rays led one expert to question the connection.

"They found a small risk (from) a pair of bitewings, but not a full mouth series, which is multiple bitewings. That inconsistency is impossible to understand to me," said Dr. Alan Lurie, president of the American Academy of Oral and Maxillofacial Radiology.

So non-connection was massaged into a connection. Fail science if you ask me.

Re:Small study? CT of brain?? (0)

Anonymous Coward | more than 2 years ago | (#39631465)

Probably an artifact of their sample method: Take people with the most common brain tumor, and find the most common things they all did. Exclude the stuff like "eat food" and "breathe air" and see what's left. It's not a good way to find anything except what was already blindingly obvious.

That said, if you want to keep your tinfoil hat on, you could suggest that having the full X-ray done would be more radiation and causes a rarer type of cancer, pushing the people who got cancer from the x-ray out of the sample group.

Dentists Are Not Doctors (0)

Anonymous Coward | more than 2 years ago | (#39631095)

So they may not know that much about what the X-ray does to other parts of the body.

Cover your self (0)

Anonymous Coward | more than 2 years ago | (#39631113)

I always cover myself with lead before I get an x-ray.

Correlation != Causation (0)

Anonymous Coward | more than 2 years ago | (#39631683)

Big news ! People who take care of their health are more likely to be diagnosed.

This is bizzare (2)

sirwired (27582) | more than 2 years ago | (#39631949)

Firstly, where did they find their sample of people who have never had bitewings taken? If you've EVER received a dental exam, the dentist almost certainly took a set of bitewings, and probably a panorex.

If you've actually never had bitewings takne, you probably aren't receiving dental care at all. And if you aren't receiving dental care, it's a safe bet that you are more likely (though not certain) to not be receiving quality medical either. Meaning you could have a menengioma and die without it ever being diagnosed.

And please, please, note that even the study stated these results were based on far older radiation levels. Today's x-rays don't need nearly as much.

Given that dental abscesses can be fatal if untreated, (in addition to poor dental health being linked to stuff far more common and deadly than brain tumors), don't refuse dental x-rays based on this report.

Oops! (1)

scharkalvin (72228) | more than 2 years ago | (#39631993)

I've been having problems with frequent headaches recently and I was worried that I might have a brain tumor or something. I've been to a neurologist who had me get an MRI to eliminate that possibility (which BTW it did, phew!). I've had enough dental xrays over the years, but rarely a full mouth set. Most of the time the dentist would only take views of any teeth that looked problematic visually, or if I was complaining of pain and nothing was visual in that area. I also had localized views taken before root canal work, and before a possible tooth implant (I didn't get the implant because the Xray reviled that I had insufficient bone density in my jaw to support it. I got a bridge instead). So dental xrays are useful as a diagnostic tool (especially before possible surgery), and a good dentist will do as much as possible visually before taking one. I still don't know what is causing my headaches, but the problem may be dental related ... seems I grind my teeth in my sleep and I now have a bite guard I wear and night.
 

Meningioma (0)

Anonymous Coward | more than 2 years ago | (#39632053)

You see the burnt out calcified husks of meningiomas in about 5% of all CAT scans of the brain, which are done pretty often. Something like 0.05% of them are malignant, and maybe another 0.5% grow in areas where they push on the brain to cause seizures.
 
It's the least interesting tumor you can have, almost guaranteed not to kill you.

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