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Dental X-Rays Linked To Common Brain Tumor
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."
A valid reason to avoid the dentist
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.
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.
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.
This Space Intentionally Left Blank
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.
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.
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.
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.
are sources of non-ionizing radiation.
Well, at least our friends in the UK won't have to worry about this... :P
A computer once beat me at chess, but it was no match for me at kick boxing. Emo Philips
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?
:wq
Not worried until the X-ray powered cell phone is released.
Everybody with half a brain probably had too many x-rays.
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...
Hey look, a stupid, panicky post made in repsonse to "brain tumor" and "radiation" with not a shred of accuracy.
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.
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.
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.
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
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.
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
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
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.
So, not that huge an increase.
Actually 46% is a huge increase.
This issue is a bit more complicated than you think.
- 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.
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.
Why are other peoples sig's always more witty ???
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.
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?
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.
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.
I am TheRaven on Soylent News
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.
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.
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).
I'd give my right arm to be ambidextrous.
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.
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.
Account -> Discussions -> Disable Sigs
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.
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.
"When information is power, privacy is freedom" - Jah-Wren Ryel
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.
According to the EPA (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.
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.
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.
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
"-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."
:(){
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.
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, 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.
Apocalypse Cancelled, Sorry, No Ticket Refunds
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.
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.
I think you will find that people died of brain tumours even before the mobile phone was invented. What was your point?
Quidnam Latine loqui modo coepi?
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.
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.
I don't read your sig. Why are you reading mine?
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.
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.
I don't read your sig. Why are you reading mine?
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.
Is there ANY truth to this? Where does the 1/100 come from? It's hard for me to believe it's just a complete lie, especially considering you're talking about being off by a factor of 50.
AccountKiller
The higher the frequency, the higher the energy. You can throw as many low-energy photons at something as you want (let's disregard extreme cases like MW lasers firing at something), but you won't ionize anything. You'll just heat it up.
Quantum physics 101.
Don't forget cell phones operate below 2.4GHz, so it's an even bigger difference between RF and ionizing radiation
So, you're proposing we only use 'old technology'.
That means Film X-rays vs digital ones that reduce radiation exposure 50-90%
Rather than using digital cell phones transmitting 1/4 watt, we'd be using analog ones that transmitted at 4 watts.
Rather than using wifi, we'd just stick with old portable phones - 2.4Ghz, right next to your head, at like 10X the output.
The list goes on. As mentioned in other threads here, there's a big difference between ionizing and non-ionizing radiation.
Heck, you list Asbestos as an example - thing is, we knew the stuff was dangerous back before WWII, it's just that in the war rush we disregarded it in favor of getting more ships out.
In the end, you go back 'a few generations', you'll see more pollution, radiation, and other hazards at far lower utility level. We've done a lot in identifying causes of damage rather than just finding correlations between use of certain types of equipment and the condition being tracked.
I don't read AC A human right
Alpha particles are He2+ ions (that is, a pair of protons and a pair of neutrons with no electrons) and beta particles are electrons. However, neither of those penetrate matter very effectively, while gamma rays (i.e., photons) do.
Which is why you should be checking the sample size first. Saying "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,". It's easy to understand IF you look at the sample sizes.
A 4W handheld CB at 27MHz will light up a neon tube when you bring the antenna close to the bulb.
Cell phones star at 800mhz and most in the US are at 1800-1900mhz. That means touching the tube.
Here is the study itself. Ignore the media, they're obviously idiots.
http://onlinelibrary.wiley.com/doi/10.1002/cncr.26625/abstract
There are too many variables left untouched. The only reason this is getting attention is because it's from an Ivy.
Are these digital radiographs (formal term for "x-ray")? Are these older film radiographs? What other sources of radiation are these people exposed to? What were their settings for each capture? Is it confirmed and documented? Are they travelers?
Obviously exposure to ionizing radiation is bad. No one is arguing that. However, in terms of damage, you just threw a pebble at a canoe in the water.
A radiograph from a general dentist, be it bite-wing or periapical is about 1/2 the daily background radiation exposure per shot.
Panorex (the thing you bite down and another thing goes around your head... most common when you see an oral surgeon to get third molars removed or an ortho / perio / prostho) is obviously more radiation exposure. While it is a fairly centralized beam, there still is scatter as it moves around your head.
Then if you see an orthodontist, you'll probably get something called a lateral cephalogram which is even more with a larger exposure target (includes brain).
In the dental community, there is a LOT of skepticism and unanswered questions.
Oh since this is /. here is a obligatory XKCD - http://xkcd.com/radiation/
Given the chart I linked and it's relative accuracy, these people would probably blame a Sinal CT on Kennedy getting shot.
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.
Mine said 1/10th, for what it's worth. And I was getting the first in quite a while, coming in for a root canal (the crown had broken off due to some major decay), so I really did need full bitewings.
It was pretty freaky to find that X-rays were now being done with a USB imager.
#naabhaprzrag, #sverubfr-000, #agi-fcbafberq, negvpyr[pynff*=' negvpyr-ary-'] { qvfcynl: abar !vzcbegnag; }
Before you indirectly attack Wi-Fi (even if that wasn't your intention), please try and find a biological, chemical or physical mechanism for cancer to develop due to microwave radiation.
Well gosh, I think there was about zero Hg in the many fillings I've been getting the past few months. They're ceramics (with color matching done before mixing the stuff up) that cure with a light "gun" that probably emits UV for the curing process. The difference shows up on an X-ray, but otherwise it's not visible.
There's no point in using metallic fillings unless you really want to show off your bling every time you smile. (Plus, the dentist has to keep track of some really expensive metals that can potentially be stolen.)
#naabhaprzrag, #sverubfr-000, #agi-fcbafberq, negvpyr[pynff*=' negvpyr-ary-'] { qvfcynl: abar !vzcbegnag; }
That is called a digital intraoral sensor.
The thing where it's directly against your cheek is called a periapical radiograph. (from above the tooth to root structure).
The thing where you bite down on is called a bite-wing (go figure).
Digitals are such low doses. However you should always get a lead shield on you and the practitioner should leave the room. You might get it once every 6 months, but I do it 10 to 15 times a day. Deduced from this article, all dentists by the age of 50 should be similar to The Toxic Avenger.
I have a buddy with this huge gap right in the middle of his upper front teeth. Other than that he has perfect teeth. Years ago he went in to get a small gap closed and the idiot dentist actually spread the gap wider instead. I don't know how he couldn't tell it was going the wrong way while it was happening. After it was done apparently all the rest of his teeth were scooted by it and closing it now is not a simple procedure so he just left it. HUGE GAP for no reason.
Cwm, fjord-bank glyphs vext quiz
I was using it as an example of "unknown" that some people go nuts about. The worst I got from wifi was headaches when near a transmitter (back when they first came out, it became an excellent way of telling if there was a wifi network nearby I could use without having to take out and boot up my laptop), or a very long migrane after I stuck my head in-between a very powerful point to point microwave link (it was not supposed to be running at the time).
I think the "OMG wifi is giving me cancer crowd" are in major panic mode. The reality is we don't know the side effect of slowly heating our heads with microwave radiation will do. Wifi is at such low levels I don't think it really affects us adversely in any way. At high levels microwave radiation is dangerous, stick your head in a microwave and turn it on. You'll be lucky to be alive or not a vegetable by the end of it (although you'll most likely go permanently blind in either case).
Cancer on the other hand? Don't think wifi can cause it that way, but as long as there is doubt, people will panic about it. If you want a better explanation of what I meant, see my post in response to Firethorn above.
Hate to burst a bubble but pretty much all 'medical' practitioners from acupuncturists to neurosurgeons have limited oversight and do things that, in retrospect, seem batshit insane.
Health care can be a big gamble, some things work, a lot don't. In general, I think we're improving all of the time (Big Pharma being a notable exception) but it's not easy, inexpensive or guaranteed.
McCoy: [McCoy, masked and in surgical garb, passes an elderly woman groaning on a gurney in the hallway] What's the matter with you?
Elderly patient: [weakly] Kidney
[pause]
Elderly patient: dialysis.
McCoy: [geniunely surprised] Dialysis?
[musing to himself]
McCoy: What is this, the Dark Ages?
[He turns back to the patient and hands her a large white pill]
McCoy: Here,
[pause]
McCoy: you swallow that, and if you have any more problems, just call me!
[He pats her cheek and leaves]
Faster! Faster! Faster would be better!
Yep. No more mercury poisoning. Now we'll get UV radiation induced skin cancers inside our mouths.
Science marches on!
(Only half kidding.)
Faster! Faster! Faster would be better!
So, basically, the GP is totally, utterly debunked in every aspect and every statement.
"The agriculture ministry is not in charge of Gundam" - Japanese ministry official.
Don't have time to post it all out, put it's easy to compare energies of photons at various frequencies at Wolfram-Alpha. Very instructive exercise left to the student.
Faster! Faster! Faster would be better!
Good. At the rate this society is going we'll have completely cured brain cancer in a decade or so.
Faster! Faster! Faster would be better!
Sheesh... just to completelly extinguish this little dental X-ray conspiracy bonfire, the dental X-ray uses less than 0.01 mSv, here on this petty children's playground, they are receiving 6.40 mSv (600x more), and it is considered harmless by most of those not yet green glowing Japanese authorities.
http://www.youtube.com/watch?v=BOIDFh3wPXY
Now replace dentist with an other profession, for example programmer, and the job with programming, and presto, you got a very recognizable story. In short: in every profession the majority just fucks up very often.
Perl Programmer for hire
Exactly. These sorts of 'memory recall' studies usually never pan out. I don't remember what x-rays I got 10 years ago. I can't even remember the details of my last series (did we do a bite wing? an apical? was that the time I was dealing with the root canal?).
But now you've got enough data to go and scrounge for money for a prospective study. This is all well and good, I can't come up with a better way to do science in our current environment. But don't stop the presses just yet.
Faster! Faster! Faster would be better!
In places like
the Free Enterprise Radon Mine.
Personally, I wouldn't bother, but then I'm just some propeller head geek who looks at books all the time.
I bought this house and you know I'm boss
Ain't no h'aint gonna run me off
Very, very early x-ray machines used considerably more radiation. Over a thousand times as much, according to some.
http://abcnews.go.com/Health/Wellness/century-ray-machine-shows-radiation-risks-yore/story?id=13140857#.T4R5CtXe4tY
I would imagine that it is possible to find a band of time over which radiation has decreased by 100, but how useful is it as a measure? Does it really matter that an x-ray machine emits 100x less over the course of a lifetime, or even a decade? If the dosage was so great a decade ago that it is still significant in dosage calculations then that is what we should be concerned about, not what the exposure is today.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Deduced from this article, all dentists by the age of 50 should be similar to The Toxic Avenger.
Why? the patient is being subjected to radiaiton; my dentist leaves the room.
Nope, didn't address your neon tube, which we all know lights up from a motherfucking glow discharge, which occurs when the field strength is approximately equal to the breakdown voltage. This has nothing to do with ionization by absorbing radiation, which CAN'T HAPPEN without a suitable frequency.
Did you even read the page you linked? Did you notice it said nothing about production of free radicals in the near-field with radio-frequency radiation? Because it DOESN'T HAPPEN!
Sorry, but my main objection to both the claim and counter-claim is that this is journalism, not science. Can't someone provide links to PLoS One papers? Arxiv? Cancer research group websites? I'd ask my uncle, who was a statistician specializing in cancer research, but he's retired and won't be on the cutting edge any more. This needs to be answered by researchers who have that up-to-the-microsecond knowledge.
However, I'd also point out that the "dramatic reduction" you speak of is questionable. I've seen no reliable figures showing it is dramatically better (dentist offices don't have on-site engineers, won't maintain equipment any more than they have to and are unlikely to have staff highly trained in the use of systems - more likely they know how to press a button but don't know how to adjust settings according to any manual that may exist).
Further, 20-30 years ago, fewer people would have had "routine" X-Rays than today, so even if the per-session dosage is actually lower, the net dose over the year might actually be greater. Instantaneous dose isn't important.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Now I know why the dentist next door goes through so many dental hygienists...
Oh it's not a complete lie, they take the most sensitive sensors that QA can find, expose it, run massive computer enhancements on the image and compare the results to a film that was obsolete 30 years ago; wash, rinse repeat, tweeking everything to make them look the best and publish the results.Production sensors Vs. a modern film, not as much of a slam-dunk.
Apocalypse Cancelled, Sorry, No Ticket Refunds
It's all so clear now! Brain tumors cause mobile phones!
I am a radiation expert. Occupational instead of medical, but radiation is radiation and x-rays have the best understood physics. Theory says injury is proportional to dose. Dose is independant of type (i.e. 1 rem of gamma should give the same effect of 1 rem of x-ray.) So if this data is correct, we would see an obvious increase of brain tumours among occupational workers at these low levels (which we don't even among occupational x-ray workers) and increases tied to areas of increased background radiation. Also, in the article, the study was retrospective, asking people if they remember having such dental procedures. From my work, I can say with confidence that people with cancer will always remember a cause for their cancer, particularly if it is phrased as "Do you remember being exposed to yada-yada as a child?" For a similar issue, look for cancer-from-transformer stories. Researchers asked if the people remembered living near elictrical transformers and those with cancer or cancer in their family remembered the transformers at a greater rate--leading to a statistical result similar to the one in this article.
> 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.
Wow... agreed! My mother was an X-Ray tech for about 25 years (until she ended up on disability for unrelated reasons). When she started back in the 60s/70s she was told "by choosing this profession you are taking 7 years off your life".
Admittedly she was a hospital X-Ray dept tech, so she did them all day long, and with a machine that enforced being in a different room... unless it was a portable X-Ray but thats another story.
Even at all that, I seem to remember there were a handful of times where her dose was high enough that she was given some mandatory time off work. I can only imagine what a dentist in the room is doing to themselves.... how many times a day do they take x-rays?
Also, for anyone interested in how bad X-rays used to be... my mother was fond of pointing out how much better soft tissue xrays were back in the 50s when they could use thorium as a contrast solution :) great images..... just didn't work out so well for the patient.
"I opened my eyes, and everything went dark again"
All your post states is that you don't understand radiation.
You certification means you can operate the q\equipment with minimal safety guidelines, and that's it.
You are not an expert, scientists, or specialist. Please leave the science to actual experts and stop waving your certificate around like it some how adds validation to anything outside the operation of you job.
I hate it when people get a piece of paper in one things and then think that makes them an expert on everything.
.
The Kruger Dunning explains most post on
Looking at your article, I'm left wondering, if the H and E fields are so capable of ionization, why aren't MRIs giving everyone cancer? I mean, an MRI has up to seven Teslas of magnetism. Around ten Teslas you can make frogs levitate. Ten Teslas is way fucking bigger than any H field you will see in the near field, I don't care if you're just one angstrom away from the antenna.
As far as glow discharge, the glowing is not caused by the electric field ionizing the atoms. Rather, the electric field accelerates the electrons, and when the accelerated electron slams into an atom, *that* causes the ionization. Those glowing tubes that you mentioned earlier? Did you know that sometimes they put in a trace of radioactive gas to help seed electrons in the tube? You only need a few to start, and once they get moving they cause more, kinda like a nuclear chain reaction.
It sounds like you should do some more research on dielectrics and breakdown voltage. You seem to think that dielectric breakdown causes ionization, when the reverse is actually more true; ionization reduces the dielectric constant for the path that has been ionized.
:(){
The only time dental mercury was a problem is when people have it procedural removed.
The Kruger Dunning explains most post on
people using actual science and real numbers to bring up facts that need to be taken into consideration whenever discussing the topic, and you don't like that..why?
Not alarmist enough for you? FLies in the face of your pseudo scientific belief system?
The Kruger Dunning explains most post on
With dentists, just like doctors, they're not all equal. Some are downright incompetent. Plus, just like with surgeons, dentistry is a very hands-on profession, making it a real art. Not everyone is gifted with great dexterity and the ability to do extremely fine work. If the dentist you're seeing is saying things that bother you, you should go visit a different dentist for a second opinion.
Yep, I've gotten quite a few fillings in the last 10 years, and all of them have been resin type fillings; my dentist doesn't even use the amalgam stuff any more as far as I know.
Acupuncture? Seriously? In a discussion about the medical field? How in the world do these "acupuncturists" continue to peddle their bullshit as if it was some actual therapy? I'm not trying to give you shit, specifically, but putting acupuncture in the same breathe as neurosurgery is quite a stretch.
kurzweil_freak
5th Kyu Genbukan Ninpo/KJJR student
Be the darkness that allows the light to shine.
Clearly, playing tennis causes brain cancer!
kurzweil_freak
5th Kyu Genbukan Ninpo/KJJR student
Be the darkness that allows the light to shine.
Why do so many people say "lie" when they mean "incorrect". Lying is when you intentionally mislead people. Parent may (or may not be) incorrect, but I doubt they're trying to pull a one over on you. -- I don't like programmer humor. Not one bit.
"There isn't a real-world problem I've come across that doesn't have common human ignorance at its core."
Actually, there is a mechanism, called tunneling ionization where the electric field is not enough to remove the potential hill the electron has to climb to get out of the atom, but does shrink the size of it so that the electron can with a small chance tunnel out. The effect is exponential with respect to electric field though, with a growth constant such that it goes from very quickly not mattering to mattering. But the other AC is still crazy, as even at the fields strong enough to cause breakdown in air, the tunneling rate is very, very small. Instead breakdown depends more on background ionization from thermal collisions, background radiation, or chemical sources of ions floating around in air.
Breakdown is sensitive to the electric field strength, because the stronger the field, the faster it can accelerate liberated electrons into other atoms causing them to ionize from collisions. However, this also means it is sensitive to mean free path, because if the electron hits another atom before it accelerates enough, it just bounces around without creating more ions. This is why it is easy to get breakdown in a neon lamp/tube, because it has a low pressure, and electrons have a longer mean path. It takes stronger fields to cause breakdown in air at atmosphere pressure, and it takes even stronger fields in typical solids and liquids. As further contradiction to the idea that these fields just cause the ionization themselves, as you lower pressure, breakdown first gets easier as mean free path increases, but eventually gets more and more difficult as there are not enough sources of electrons (i.e. most of the atoms are not ionizing, and the few random background ionization rate is too small and there are too few collisions with free electrons to cause a cascade). If the electric field was all that was needed for ionization, you would see complete ionization at lower pressures, regardless of pressure. Even in cases when there is a breakdown in air at atmospheric pressure, typically only 1% of the atoms are ionized or less.
So yes, you can get ionization from a field only, although the near field around your phone would need to be stronger than what is needed to create a corona discharge, so you would quickly notice if the near fields were anywhere near strong enough. Otherwise, electric fields just act as an amplification effect to ionization, and just because it works in a neon lamp doesn't mean it is doing anything in denser materials, and if it were, you could easily observe the effects via measuring the current flowing through the material.
I'm not a physicist, but your argument doesn't sound like any excuse to call RF "ionizing radiation". If you can only throw a ball halfway out of a well, and you throw a ball to someone reaching halfway into it from the top, you don't call that "throwing a ball out of a well".
Actually, there's reasonably good evidence that low dose ionizing radiation, such as from normal or abut above normal background is good for you, and it doesn't do any good to make up facts.
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.
That won't do either. Photons are not billiard balls. In the quantum world, only frequency (wavelength) attributes to the effect, not intensity. See http://en.wikipedia.org/wiki/Photoelectric_effect.
Anne Coulter said that radiation is good for you. The rest of the bat-shit crazy Republican mediasphere echo chamber repeated this claim.
There is no evidence for this statement.
Here is a cogent science-based article about this craziness. I don't expect you to read it or understand it but someone else might be interested.
http://www.sciencebasedmedicine.org/index.php/ann-coulter-says-radiation-is-good-for-you-2/
I don't read your sig. Why are you reading mine?
High tension lines... You know if you get too close to a high voltage DC line you get zapped too hey? The damage isn't from getting your atoms ionized, it's from all those electrons from the power line or antenna wanting to be in the ground and deciding your body is the best way to go. And the damage is thermal.
I presume slashdot ate your unicode, as *grams* of Hg per litre wouldn't be very healthy.
What was the unit supposed to be? Micrograms?
We did the math in our electromagnetics class where we compared the energy delivered to a person standing near a high-voltage power line. It was less than the thermal energy of a human body.
No, he's not. You, and he, are making a difference of diffences error, which stems from the erroneous belief that "no statistically significant difference" means "no difference."
The GP is (mostly) correct, you need to know the two effect sizes (which depends on the difference of means and std errors for many tests) and construct confidence intervals or otherwise test to see if the one result is inconsistent with the other.
No, it isn't. It looks huge, but meningioma is rare so the increase is not that big in absolute terms, only in relative ones. It's a common trick in sensationalist reporting of medical study results.
While your links were interesting, the near-field link says nothing at all about creating ionizing radiation, and the situation it describes is in the context of high energy industrial equipment. I asked for evidence that cell phones create ionizing radiation in the near field and you have not provided it. Instead, you've ranted about physics illiteracy while giving rambling discussions on a number of topics and insulting everyone repeatedly. That is not a good way to get people to listen to you regardless of the merit of what you have to say.
Is that all you've got?
Were you going to offer some insight of your own?
Tell me - if you're not an expert either, how are you qualified to dispel the other guy's claims?
This seemed like a reasonable sig at the time.
Yes, an electric field induces a force on ions, and in biological matter that can induce a current. Hence why flesh is far from a perfect insulator. If you want ionization though in a process similar to glow discharge, you need both an electric field and sufficient mean free path to allow ions or electrons to be accelerated to a kinetic energy comparable to the ionization energy of the atom (you don't need to hit an atom with a photon to do it, hitting it with any other particle that interacts electromagnetically, with sufficient energy, will also ionize the atom). And if you had a sufficient field to overcome the mean free path issue, you don't exactly need to worry about ionization any more, but instead about the cooking quantity of heat from the massive current density that results from plain old Ohmic losses (from all of the nonionizing collisions that happen between charge carriers and components of your flesh).
For example, if you want to accelerate electrons, with a mean free path of ~100 nm in water, to an energy of 0.025 eV, which would get you only the same effects as thermal collisions already constantly happening within your body, you would need an electric field of about 250 V/mm. Using a conductivity of ~1.7 S/m for one model of muscle tissue at 2.4 GHz, this would require 0.4 A, or a power of 100 W for a single cubic mm to reach those potentials. In other words, the kinetic effects of accelerating charges that are important to glow discharge are not relevant to a body under regular conditions (by regular conditions, I mean rare, not medium-well).
Also being near field has nothing to do with it. Regardless of if it is near field or far field, either the electric field is strong enough for said effects, or not.
Every office is different, of course, but I took an average of 20-40 radiographs a day. There were usually 3 of us who each took that many. The dentist never took any, and wasn't any good at it at all.
+5 Informative? Really? Basically, you said We are looking at a sample of 15 - after that your math is worthless. They said 15 out of 10,000, and if you RTFA, the sample size is stated at 1350.
You can re-do your math for partial credit, but my point still stands - 15 to 21 IS a huge increase, even if 15/10000 vs 21/10000 is not a very big number.
Jerk (he says, ironically belittling his own point).
This issue is a bit more complicated than you think.
> You absorb 200 times this amount every year, year in, year out. all your life.
Its not the magnitude, its the rate at which its administered.
> Dental X-ray uses less than 0.01 mSv per image.
Actually: "Dental radiography: 0.005–0.03 mSv"
http://en.wikipedia.org/wiki/Sievert#cite_ref-ecds_5-0
Cute - thanks. Yeah, definately g (alt-230)g [micrograms]. And I'm not sure why it goes through as something other than extended ascii. Perhaps that's slashdot's text entry system, or maybe it's higher up in Firefox...
I hate it when people get a piece of paper in one things and then think that makes them an expert on everything.
And your credentials are?
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
That says 6.40 *micro*sieverts per hour, not millisieverts.
http://bjr.birjournals.org/content/78/925/3.short
http://informahealthcare.com/doi/pdf/10.1080/20014091111956
etc.
There is evidence. Please don't get your science from crazies like Coulter or reactions to them. The SBM article you link to is quite rightly addressing refuting Coulter's claims, but there is reasonable evidence that radiation exposure at levels quite a bit less than what Coulter and the SBM article are talking about, and similar to what we're talking about here, may be beneficial.
Yes, I should have said "may be beneficial." The evidence is stronger that normal background-level radiation has a beneficial effect than that it has a clinically significant detrimental effect. Your statement that "radiation is bad in any amount" is unfounded. You also didn't distinguish the type of radiation - the vast majority of radiation people encounter in their daily lives has a variety of very beneficial effects.
X-rays are ionizing radiation which removes electrons from atoms creating ions. Ions cause direct damage to cells (radiation poisoning) and have the potential to damage DNA causing cancer.
There is no evidence that ionizing radiation has any beneficial effect on living cells. It damages cells and DNA.
Some people have postulated that since the damage stimulates the body to react to the inflammation and repair it, there is a net beneficial effect. This is like saying it is good to beat your head against a wall since your body will try to repair the damage. The net effect is damage to your body which does what it can to repair the damage but you are still better off not beating your head against the wall. Scar tissue is tough but doesn't work as well as normal tissue. Constant inflammation from radiation damage (or any other cause) leads puts the body in a constant state of repair and has no net beneficial effect (besides getting better at repair). There is no net benefit. This does not stop some wishful thinking radiologists from postulating otherwise.
I don't read your sig. Why are you reading mine?
If you had pants on, then there would be no skin to skin contact. Chances are you also had a 1.5T scanner, or maybe 3T, where the risk of burn is not as great. 7T is pretty scary IMO.
If you have the stomach for it, you can do a google image search for "mri burn" and you'll see some pretty nasty ones.
By the way, I hope you get well soon.
:(){
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.
I have scanned the original paper http://onlinelibrary.wiley.com/doi/10.1002/cncr.26625/abstract as well, and it is not very impressive as to its use of statistics. This AC in the thread gets the statistics right with respect to the original paper: http://science.slashdot.org/comments.pl?sid=2777187&cid=39634199
But back to Dr. Paul Pharaoh's claim and correct use of Poisson statistics. When using Poisson statistics, the sample size is the number of positive events not the total population under study, in this case the 15 people with meningioma. One standard deviation is Sqrt[sample], so rounding to 4. This means that for any group of 10,000 people, there is a 68% chance that the number with meningioma is between 11 and 19. Similarly for that 22/10,0000 estimate, one standard deviation is Sqrt[22] ~ 4.6. For any 10,000 people in that group the odd are 68% that there will be between 17 and 26 people with meningioma. So we can see that there is overlap between the two expectations. From the 15 number to the 22 is about 1.8 sigma, and while 1.8 sigma hints at a result no self respecting physicist would publish that as a result; they would want to get at least three sigma certainty. And this report is no where near 3 sigma.
You state your claim of a 46% increase with a certainty that is not supported by the statistics. In some cohorts of 10,000 it is 46%, but in about the same number of cohorts it is 0%
A recent editorial in Nature comments on directly on sloppy use of statistics in cancer research: http://www.nature.com/nature/journal/v483/n7391/full/483509a.html
improper use of statistics — the failure to understand the difference between technical replicates and independent experiments, for example.
It is relevant to the paper and our discussion.
For in-depth discussion on my above work I recommend my favorite statistics book, which has good coverage of the use of Poisson statistics: An Introduction to Error Analysis by John Taylor ; http://www.amazon.com/Introduction-Error-Analysis-Uncertainties-Measurements/dp/093570275X - suitable even for a Frosh E&AS major.
* It is possible that clever use of Baysian statistics could push the sigma of the origial paper past 2, but I'd be surprised if they could get to 3.
I do enjoy how you reply to a couple of peer reviewed journal articles with nothing but assertions of truth and your own poor analogies. Bravo.
You are right. I should have responded in more detail to these two articles but I didn't have time yesterday.
They are both review articles where the authors did not do any research themselves but pick research which has been done by others and fit it to a "hormesis" model which seems to be trying to hypothesize that there is some type of "immunity" induced by radiation exposure.
The BJR article cites protection of 30% or 40% from further damage due to adaptive responses in some papers and then goes on to the (untenable) assertion that this "could" lead to more than 100% protection (immunity effect) if you extrapolate their curves. However, there is no evidence for more than 40% protection from further damage. The only thing the articles have shown is that there is a non-linear dose response curve to radiation damage. They have not shown any net protective effect.
The second article is gated so I only have access to the abstract which states: " As yet, however, the extent to which such responses may actually reduce the risks attributable to low-level irradiation remains to be determined, pending further elucidation of the relevant dose-response relationships and the apparent lack of responsiveness in some individuals. Therefore, further research is needed to resolve this question."
All of the articles have shown damage from radiation at all doses. Some of the articles show that the body attempts to repair the damage and that the repair mechanisms may mitigate the damage. None of them show any net protective effect from radiation exposure.
I don't read your sig. Why are you reading mine?
The second article reviews a bunch of studies in a bunch of plant and animal species, showing lifespan extension, improved immune function and better reproductive success when exposed to various low level doses of ionizing radiation.
You're right, there isn't any absolutely conclusive evidence that low dose ionizing radiation is beneficial, but there also isn't any evidence that it's harmful either. Your statement "there is no net benefit. This does not stop some wishful thinking radiologists from postulating otherwise" is unjustified, as is your original statement "radiation is bad in any amount and it doesn't do any good to deny this fact."
The immediate never mind long term carcinogenic effect of very low dose radiation is not settled either way even in the simple case of cells. You can trudge through the related links and responses to them at :
:-)
http://en.wikipedia.org/wiki/Radiation_hormesis
if you want to bore yourself.
The problem is it's very difficult to detect the difference between a small negative effect and a similarly sized positive one. Plus due to complicating effects like the bystander one it is likely that the pattern, flux and nature of the applied radiation will complicate the results.
At such low radiation levels in more complex organisms to know for certain you would need to have an unethical massive experiment using millions of animals with half being irradiated in a precisely controlled way. Rightly so this doesn't happen and so researchers have to look at smaller samples often with massive variations between them. Which is why the issue is not settled.
O and all radiation isn't bad, look at radiotherapy
"O and all radiation isn't bad, look at radiotherapy :-)"
Forget radiotherapy. Look. You're seeing radiation. It's kind of handy.