X-rays cause cancer?!

[LucidDreamer]

Krystal, here are two websites that may be of some interest to you. http://www.orau.org/ptp/collection/shoefittingfluor/shoe.htm

http://www.mtn.org/quack/devices/shoexray.htm

It's hard to know whether any health problems that you may have are related to the flouroscope. Some things like cancer have been liked to radiation, but many other diseases have no known links to radiation.

[Guest Krystal]

Thankx LucidDreamer I will check those sites out. Krystal

[jdurg]

The whole thing about radiation and cancer has always confused me to no end. Everything seems so contradictory. Radiation supposedly causes cancer by altering the DNA of cells which are in the process of dividing. This causes a gene mutation which MAY result in a cancerous growth. (Though what's more likely to happen is that the body will terminate the cell when it notices the damage to it). So radiation is more damaging to parts of the body which have a high rate of cellular growth (Genitals, bone marrow, internal organs), as opposed to parts of the body with very little cellular growth (skin, extremities, etc). Radiation is thus able to work as a very effective method of cancer treatment since cancer cells divide very rapidly and are far more susceptible to being killed by the radiation than 'normal' cells.

 

So because radiation damages rapidly dividing cells more readily than normal cells, how come infants and teenagers don't have the highest rate of cancer amongst all humans? If X-Rays and the like were so dangerous, you'd figure that infants and teenagers would be incredibly prone to getting cancer since their cells are dividing at an incredible rate. Yet we really don't see that. We see cancers developing more in eldery people than we do in the young. So I think there's something in relation to radiation and cancer that we haven't fully grasped yet.

 

As for why the dentist/radiologist leaves the room for the x-ray, it's pretty much just a matter of reducing the quantity of radiation. The amount of radiation in one x-ray is next to nothing. It's a little blip on the overall scale and you get far more radiation from going outside to get the mail than you do from the x-ray. The thing is, the dentist/radiologist performs a lot more than one x-ray each day. If they have a lot of patients they may take a few dozen x-rays every single day. So while one isn't going to do anything, if you start adding them up the overall dose becomes much higher. I guess you could look at each x-ray like a marble. Just one isn't going to cause much damage to you, but if you fling a lot of them at you it can cause some major pain.

[Krul]

To understand what X-rays ( and other radiation types ) can cause you must understand what cancer is:

 

If you really want the ( very ) long explanation I can give it, but it is much more simple with a paralel;

 

Imagine a tumor caused by radiation, as a weed in a nice garden. Now this weed will grow fast or slow depending on the type of cell they originate from and if they are benignant or malignant. If not removed/treated the weed will overgrow others plants in your garden, which you do want, or the weed can put chemicals in the ground which can hurt the other plants.

 

Now where this weed came from is simple; It is a mutated plant, the radiation damaged the plant so much that it became a weed. Normally the plant does not get damaged easily, it has protections against all types of damage, but at a certain point those protections are no longer enough and then the transformation from plant to weed is complete.

 

So a little radiation we can take, however when you have been exposed constantly for a long time it gets very unhealthy.

 

 

 

 

Jdurg: MOST types of tumors are not caused by radiation, they can be caused by chronic irritation ( even strings can be enough if constant ), a wide number of virusses, genetic disorders etc.

 

Old people are more prone to tumors because their "repair systems" are not as good as they are with young people. Further very importantly, MOST tumors take years to grow to any significant size.

 

Cervical tumor for example takes between 15-20 years to go from the irritated cell to the stage at which you can talk about cervical cancer.

[Dapthar]

But to be on the safe side, thats why all the dentists run outa the room when they x-ray your teeth

Actually, they leave the room for a very good reason. Think about it for a moment. When you go to the dentist and have a diagnostic x-ray of your teeth made, it is most likely the only time during the year that you are exposed to a relatively high amount of x-ray radiation.

 

However, for the dentist, you may be their 3rd patient that week. Thus, if they stayed in the room when all of the patients have their x-rays taken, they end up exposing themselves to much higher amounts of radiation over the course of a year, increasing their risk for cancer.

[jdurg]

Another thing with radiation and possible cancers is that radiation affects certain parts of the body with more vigor than others. Your extremities really don't feel much of an effect at all from radiation. An equal dose of radiation to the hands/feet, torso, head, and genitals will be far more damaging to the genitals and torso than it would be to the hands and feet. Those foot x-ray machines are not nearly as bad as some make out to be since the radiation exposure one receives is to their feet which are pretty non-reactive towards x-ray radiation. The problem lies with the fact that there isn't a whole lot of protection on those things to prevent stray x-rays from hitting people in the torso area where radiation is a bit more damaging.

[-Demosthenes-]

as opposed to parts of the body with very little cellular growth (skin...

When the body grows and sheds a new layer every ten days... think its pretty fast.

[hyebeh]

i think anything with a higher frequency than visible light has the potential to damage genetic information, leading to uncontrolled cell division and cancer. For example, UV rays ionize DNA causing errors in complementary DNA (something to do with dimers... i can't recall at the moment). X-rays have a frequency higher than UV and one can only wonder what havoc they can raise in cells.

[hyebeh]

Another thing with radiation and possible cancers is that radiation affects certain parts of the body with more vigor than others. Your extremities really don't feel much of an effect at all from radiation. An equal dose of radiation to the hands/feet, torso, head, and genitals will be far more damaging to the genitals and torso than it would be to the hands and feet. Those foot x-ray machines are not nearly as bad as some make out to be since the radiation exposure one receives is to their feet which are pretty non-reactive towards x-ray radiation. The problem lies with the fact that there isn't a whole lot of protection on those things to prevent stray x-rays from hitting people in the torso area where radiation is a bit more damaging.

 

Radiation would have the most affect on actively dividing cells.

[jdurg]

Exactly. Hence why the extremities are least affected by radiation. They don't have nearly the number of actively dividing cells that the torso and genital area have.

[aaronmyung]

oh gosh, I remember in grade 6. They put a heavy apron thing over my body and had a little thing xray my teeth while lying back in the chair. They went around to the other room to actually take the xrays.

 

And more recently, before getting my braces, I remember being in the room by myself too

 

I'm HURT THAT NOBODY TOLD ME!!! :'(

[x ray]

sorry to rain on your parade ''krystal''. But they where called shoe fitting flouroscopes or x ray fitters. they put out 20-75 Rems per min. thats EXTREMELY dangerose. far more than the half a second of 20 MILLIREMS which is safe for simple arm x ray

 

those machines also had only a aluminum filter for image quality. that means junior, mom ,and a salsperson where all being exposed all over. Try watching moder marvels engineering disasters #18 which tells about the machines in that epesode. using one of those machines has the effect of standing on an x ray tube with no sheilding

[iNow]

I imagine he's bought an umbrella at least once during the last three years, so rain on all the parades you want.

[tvp45]

So because radiation damages rapidly dividing cells more readily than normal cells, how come infants and teenagers don't have the highest rate of cancer amongst all humans? If X-Rays and the like were so dangerous, you'd figure that infants and teenagers would be incredibly prone to getting cancer since their cells are dividing at an incredible rate. Yet we really don't see that. We see cancers developing more in eldery people than we do in the young. So I think there's something in relation to radiation and cancer that we haven't fully grasped yet.

 

 

There are some clues to this in work being done on blood (HSC) where a damage-repair mechanism is seen to function less and less well with age. (You'll have to excuse me if I use crude phrases, but I'm not a bio person.) There are also proteins that regulate cell division. Try Googling stem cells, particularly HSC and embryonic.

[Psycho]

The whole thing about radiation and cancer has always confused me to no end. Everything seems so contradictory. Radiation supposedly causes cancer by altering the DNA of cells which are in the process of dividing. This causes a gene mutation which MAY result in a cancerous growth. (Though what's more likely to happen is that the body will terminate the cell when it notices the damage to it). So radiation is more damaging to parts of the body which have a high rate of cellular growth (Genitals, bone marrow, internal organs), as opposed to parts of the body with very little cellular growth (skin, extremities, etc). Radiation is thus able to work as a very effective method of cancer treatment since cancer cells divide very rapidly and are far more susceptible to being killed by the radiation than 'normal' cells.

 

So because radiation damages rapidly dividing cells more readily than normal cells, how come infants and teenagers don't have the highest rate of cancer amongst all humans? If X-Rays and the like were so dangerous, you'd figure that infants and teenagers would be incredibly prone to getting cancer since their cells are dividing at an incredible rate. Yet we really don't see that. We see cancers developing more in eldery people than we do in the young. So I think there's something in relation to radiation and cancer that we haven't fully grasped yet.

The whole problem with cancer is that cancer isn't one thing it is a group of different conditions that have similar, but in some cases completely different causes.

 

Cancers is more common in older people due to the fact that there needs to be a build up of genetic mutations in places such as the RAS, FAS and P53 genes, the P53 gene been prevalent in over 50% of colon cancers, this is due to the nature of what the protein does, it repairs the damaged DNA.

 

Therefore you could quite happily have a mutation in say a RAS pathway gene and everything would be fine your cells would grow faster but as soon as they fail they are destroyed by apoptosis.

 

Of course over the years you will gain more and more mutations, which I might add are extremely common to levels such as 10^6 cell divisions however most of the time the P53 protein catches these and fixes them lowering the number as well as them being in the non-coding DNA 95% of the time.

 

The once the original mutations have occurred speeding up cell growth, removing receptors that cause apoptosis, removing repair mechanisms the tutor will need to metastasis and this once again is a completely separate gene mutation. If this had happened before the P53 gene had been mutated it would be fixed but as the protein no longer functions it is free to break down the E-caherin's and connexins.

 

Furthermore other gene mutations have to occur to allow angiogenesis as to allow the tumour to grow and this alone without any metastasis can cause problems such as blocking of of the blood flow causeing strokes and hypooxygenation to certain areas of the body.

 

The reduced blood flow could also cause a clotting effect and therefore thrombus to form which is a whole other problem.

[blazarwolf]

From memory, I beleive the inventer or discover of the X-ray may have died as a result of overexposer. Its scientific fact it can. Its really a risk vs. benifit argument. Its good to be aware, and involved in your own medical care. There may be doctors out there that overzealously use the X-ray because there afraid of missing something/litigation thereafter.

[Durro]

Well, as a Radiographer, this one is right up my alley. However, it's 11pm here and I really should be going to bed. I promise to come back to this and provide an explanation of the medical use of radiation and the associated risk factors. I'd be happy to answer questions as well.

 

Talk to all you soon.

 

Durro

[Psycho]

Well, as a Radiographer, this one is right up my alley. However, it's 11pm here and I really should be going to bed. I promise to come back to this and provide an explanation of the medical use of radiation and the associated risk factors. I'd be happy to answer questions as well.

 

Talk to all you soon.

 

Durro

I'm sure he can wait another day, he has already been waiting 5 years.

[visceral]

So because radiation damages rapidly dividing cells more readily than normal cells, how come infants and teenagers don't have the highest rate of cancer amongst all humans? If X-Rays and the like were so dangerous, you'd figure that infants and teenagers would be incredibly prone to getting cancer since their cells are dividing at an incredible rate. Yet we really don't see that. We see cancers developing more in eldery people than we do in the young. So I think there's something in relation to radiation and cancer that we

.

 

Don't know much about it, but I'll make an assumption. It could be that cells get less efficient at dividing properly as they get older.

[Durro]

I'm sure he can wait another day, he has already been waiting 5 years.

 

 

Ha ! I didn't realise the date of the original post. I only joined yesterday and browsed through some of the topics of interest, finding this one. Oh well.

 

 

For what it's worth, here's my take on medical radiation exposure from a professional's point of view...

 

(I originally posted this over at the Richard Dawkins Foundation website)

 

 

When considering dosages received from x-rays, CT scans, Nuclear Medicine scans and Mammograms, etc, it's like what Einstein said about Tasmania - everything's relative. Yes, patients receive a radiation dose and yes, radiation is one of the causative agents of cancers and genetic mutations, but you have to put things into perspective and not get too alarmist about it.

 

X-rays are a form of ionising radiation - electromagnetic energy that breaks molecular bonds and allows the creation of free radicals like H+ and OH- when water molecules split. These free radicals can go on to adversely affect other molecules within the body. X-rays can also directly interact with the DNA strands in cells and may cause mutations which may either A/ have no discernable effect, B/cause cell death, C/cause the cell to start dividing in a disorderly and even uncontrollable fashion (which = cancer) and D/ if the cell is a sexual cell such as an ovarian follicle or sperm cell, may pass on altered genetics to offspring.

 

But what people have to realise is a few things. Firstly, our body's cells are continually undergoing reproduction and growth with mutations from various causes and in general, the body's immune system recognises and eliminates harmfully altered cells. Every day in your body there are events which may lead to cancer formation - spontaneous mutations in DNA, exposure to other sources of radiation, sunlight exposure, cigarette smoking, etc - but the body generally takes care of itself and repairs the damage or kills the offending cells before they take hold and get out of control. So too when a person is exposed to radiation, the body's own immune system usually takes care of the damage.

 

Secondly, we are continuously exposed to radiation through various means. Cosmic radiation bombards us despite our protective atmosphere. Radioactive isotopes are all around us and inside us already - that's how Carbon 14 dating and other radiometric dating processes can be used. There are radioactive gases in the air and radioactive minerals in the ground. A brief comparative chart of radiation exposes can be found here at :-

 

http://www.nyc.gov/html/doh/downloads/p ... _sheet.pdf

 

As you can see, people that live at higher altitudes receive more radiation (cosmic radiation) as the atmosphere is thinner than at sea level and doesn't filter the radiation as much. But what would you think if I told you that people that live at high altitudes and get more cosmic radiation actually have less cancer formation than their sea level cousins ? The answer is that there are multiple causative agents for cancers and people at altitude are generally exposed to less air pollution, toxic gases, nuclear power plant emissions etc, etc. There's not too many fast food restaurants in the Himalayas so there isn't as much bowel cancer in Kathmandu compared to say New York City. Anyhow, you get the idea.

 

The exposures received in diagnostic radiology also have to be considered comparatively. A chest x-ray dose is about equivalent to a transcontinental plane flight - high altitude flight exposes you to more cosmic radiation. Pilots obviously fly daily and aren't all dropping dead from cancer thanks to receiving one or two chest x-ray doses every working day.

 

When x-raying various body parts, consideration has to be given to how thick and dense the body part is. A hand dose is tiny compared to a lateral lumbar spine dose. Statistically, there's about a 1 in 10,000 chance of getting a cancer from medical x-ray exposure. I do thousands of x-rays and CT scans per year and so I probably cause cancer to at least one or two people a year. However, without seeming to sound flippant about it, one must realise that the other 9,998 or so people had their conditions diagnosed or excluded, their lives improved and in some case, their lives literally saved. Medical exposure to x-rays is a case of risk Vs reward, with the perceived benefits of exposure meant to outweigh the risks associated with it. The people more at risk are the ones having multiple repetitive x-rays of the same body areas using higher dosages - multiple angiograms, multiple CT scans, serial lumbar spine x-rays, etc.

 

As a radiographer, one of my duties is to evaluate the requested x-ray and determine if the risk is outweighed by the reward. I am ethically and legally obliged to refuse to do x-rays or scans that are for inappropriate reasons, are not supported by adequate clinical history, or may create more harm than good in the patient. I regularly refuse to do x-rays or scans, sometime to the anger/frustration/confusion/education of the referring doctor.

 

People might be interested to learn that x-ray doses in radiology dropped by 2/3rds in the mid 1980's. X-Rays were recorded by an intensifying screen which fluoresced in response to x-ray exposure, thus fogging the film inside the x-ray cassette proportionally to the intensity of the x-ray shadow emerging from the patient. The film was developed and the latent image appears on the film. In the mid-80's, the calcium tungstate screens were replaced by rare earth screens, and overnight, all x-ray exposures in medicine were reduced to 1/3rd of what they had been. In the 90's with advanced in digital technology, films are being replaced with electrostatic cassettes which are digitally recorded and read. This has reduced dosages even further. So 4 or 5 x-rays of one body part today is only the equivalent dose to only 1 x-ray of the same body part taken 20 years ago when I started in Radiography. And that's just in my lifetime. There have been many other advances over the last 100 years that have dramatically reduced doses from the bad old days at the turn of the 19th century.

 

But back to the present. Radiographers work on the ALARA Principle - as low as reasonably achievable. There are many tricks of the trade we use to minimise radiation dose, such as using longer focal film distances where possible, using extra filtration of the x-ray beam to reduce lower energy and less penetrative x-ray photons, using compression of body parts, using lead protection and shielding, collimating the x-ray beam to a minimum, using higher kV x-rays where possible, minimising the number of exposures, positioning radiosensitive body parts away from the entrance side of the x-ray beam, etc, etc. We make a conscious effort to reduce radiation doses wherever possible.

 

There are non-ionising radiation alternatives available in some instances, but these aren't always appropriate for anatomical reasons, technological limitations, time efficiency and/or cost. Ultrasounds don't use x-rays, but cannot image inside bone and cannot penetrate through bone or air. Some U/S scans can see small avulsion fractures or disruptions of the bony cortex, but generally can't be used to reliably demonstrate most fractures and other bony conditions. U/S is restricted to largely soft tissue and blood vessel imaging in areas not obscured by gas, air or bone. MRI scans also don't use radiation, but do use very strong magnetic fields and are therefore a contraindication for people with metallic implants, pacemakers, aneurysm clips, some joint prostheses and the like. They are also very expensive and generally have a long waiting list for imaging anyhow. MRI scans do not image air and as most scans take several minutes or more, they have trouble imaging areas that move from patient respiration such as the abdomen.

 

In short, x-rays are quite useful and play a large role in diagnosing and managing patients. They are cost effective, quick to produce and analyse, and come with only a small risk of adverse effects if used properly.

 

 

Durro