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OT- CT Scans and radiation exposure

Milacron

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Had a general physician recently recommend a CT scan on my neck to check soft tissue for source of a curious pain. I resisted this due to recent reading on the radiation levels of these things. As a point of comparison, one chest CT is around 10 millisieverts of radiation and a traditional chest X-ray only 0.02 millisieverts. That's 500 times the radiation of an X ray ! :eek:

(Alternatively I went to a specialist who performed endoscopy and gave me the all clear via that method)

Now, having said all that, if you read something like this...

Google Answers: CT Scan radiation dose

it doesn't seem so bad really. So, just wondering what the physicians on this forum might think based on the latest CT scan info ?

Also, if one had a CT scan on the abdomen area and then neck area within 12 month period, would overall radiation disease risk be calculated differently from, for example, two CT scans in abdomen area within 12 months ? (but no scan of neck area)
 
Don-
The high dose issue for CT scans is for patients who are chronically ill. Many different docs ask for scans of different areas of a given patient for different reasons. Individually, they make sense. In total, it is possible to get too much dose. As an example, there is a recent case I heard about where a patient got 23 scans during the course of a single year. Quite a dose. OTOH, these patients usually really need many of the scans - in the sense that they are usually better off with them than without them.
In your case, I would not worry about a single scan at all.
 
Had a general physician recently recommend a CT scan on my neck to check soft tissue for source of a curious pain. I resisted this due to recent reading on the radiation levels of these things. As a point of comparison, one chest CT is around 10 millisieverts of radiation and a traditional chest X-ray only 0.02 millisieverts. That's 500 times the radiation of an X ray ! :eek:

(Alternatively I went to a specialist who performed endoscopy and gave me the all clear via that method)

Now, having said all that, if you read something like this...

Google Answers: CT Scan radiation dose

it doesn't seem so bad really. So, just wondering what the physicians on this forum might think based on the latest CT scan info ?

Also, if one had a CT scan on the abdomen area and then neck area within 12 month period, would overall radiation disease risk be calculated differently from, for example, two CT scans in abdomen area within 12 months ? (but no scan of neck area)

Not a doctor, but I heard an article on the radio this morning, and the doctor was explaining the risks of ct scans. He said research shows that a ct scan can increase the likeliehood of developing a cancer by 0.1%. Don't know how accurate this is tho. The article was concerning medical fraud and how recommending certain procedures can be dertremental to the health of the patient.
 
Also not a doctor. There was an investigative TV program on CT scans and the fact that most doctors will recommend them but don't actually have a clue about the radiation level/possible damage from them. Periodic single scans were OK but the well healed up here were having "just in case something is there" full body scans without any real medical reason.

Dave
 
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I spent 23 years in R&D at a major US company - the leading maker of CT scanners. I had responsibility for several research groups, including CT. I am pretty familiar with the risks of a CT scan. My wife is a radiologist - the risk of excessive CT scans is a topic we have discussed frequently. I can say this for sure - if I were personally faced with neck pain I would see a good orthopod who specializes in sports mediciine. If he/she wanted me to get a CT scan I would get one in a heartbeat.
 
Don,

A few thoughts from a family doc on the subject:

One alternative to the CT for especially for soft tissue evaluaiton of the neck might be an MRI. No radiaton with that and excellent resolution. But there are contraindications like having pacemaker. Metal in the neck from prior surgery can be a problem too.

The radiation to the neck from a CT can be a very small concern but the same radiation dose to the head and neck is less of a concern than if given to more sensitive tissues in the abdomen and pelvis. I think it would be hard to pin an exact risk related to such a scan. I know people have made an effort to do so and a google search would likely provide numbers.

But any risk needs to be compared to risk of just being alive and doing ordinary activities vs. the potential benefit to be obtained. We take similar risks just driving a few hundred miles on the freeway, riding a motorcyle or horse for instance, and we still do that for no more of a "good reason" than to see a good concert or go to a promising tool auction or experience the exhillaration of the ride.

Bottom line is that if there is potentil benefit from the scan, do it. The risk is tiny. Depending on your symptoms, it could save you a lot of grief or even your life. It is extremely unlikely to adversely affect your health.

Denis
 
Also, if one had a CT scan on the abdomen area and then neck area within 12 month period, would overall radiation disease risk be calculated differently from, for example, two CT scans in abdomen area within 12 months ? (but no scan of neck area)

I'm not a medical doctor, but am familiar with radiation from a physics background. 10 mSv is a considerable dose. NRC guidelines limit Nuke workers to 50 mSv whole body exposure annually. Extremities are allowed a higher dose, 500mSv. The whole body exposure guidelines for a member of the general public from licensed activities is 10 mSv annual. I can't recall the exact details, but I think the neck would be considered part of a whole body dose due to the thyroid. Keep in mind, these are nuke industry rules. The medical industry has higher limits for diagnostics and treatment of disease.

Just use common sense in judgment as you have done. The effects of low level radiation exposure are still not real well understood. One scan may not account to any lasting effects, but with multiple scans, the greater the possibility of problems down the road.

I've been following this story about a small boy that was overexposed during a CT scan. An incompetent technician scanned his neck 151 times over the course of an hour. The tests were stopped only after the boy's father began to worry that it was taking too long. Supposedly the instrument was malfunctioning and not completing its cycle, but the tech just kept re-running the test without regard to the fact that the machine might be exposing the patient each time. The child had radiation burns across his neck and now has chromosomal damage.

CBS13 Investigates: Radiation Overexposure - cbs13.com
Its stuff like this that scares me away from doctors.
 
Back in 2000 I had in excess of 250 xrays in a 2 week period, not a good thing, but the probable alterative was death. Now at the ten year mark, no ill effects have come up. And even if they did, I'd be ahead of the game because I'm still here.
 
I think the real problem comes from CT scanners that, over time, increase the dosage of radiation due to wear and tear. If you're going to get a CT, all you need to do is ask the tech if the machine has been certified recently.
 
I'm not a doctor but I had 5200 rads of radiation 19 years ago for throat cancer and I'm still here to tell you about it, I would think one ct scan should not be a problem. If your neck problem is bad enough to justify it, only you can determine that. Ron
 
i am a dr. i rarely order CTs. usually i get MRIs, however CT is the standard for certain circumstances. It is quicker and cheaper than MR. 2 things FWIW:
1) the old shoe stores checked shoe size with nonshielded Xray machines
2) Old time xray film needed a lot more radiation for exposure

Given that the old shoe salesman and doctors lasted a long time with large radiation doses, i wouldnt have any hesitation in receiving a few CTs if needed. I always tell patients that if the FDA put a warning label on oxygen, you would never want to breathe again. I also explain that statistically, the drive to the drive to the hospital is generally more dangerous than the test or surgery. its all about relative risk
 
Like others have said, one scan isn't going to kill you. The risk is minor and the images are priceless if they help save your life. You are lucky to live in a country that has such amazing technology.

I'm a medical basket case and have had so many CT's I've lost track of how many. Probably around 30. I don't have an extra eye in the middle of my forehead yet. :cheers:
 
Um... As I understand it, all medical X-ray devices are based on bremsstrahlung (hope I spelled that right) radiation and that means that you have a high voltage power supply dropping electrons on a cathode in order to produce soft X-rays. High voltage supplies do drift over time. Perhaps newer systems do have some sort of drift compensation, but the information I saw said that some CT scanners were delivering higher doses than they were designed to.

Not that it's a big worry. If I needed a CT, I'd be the first one on the table.
 
I read only the first 2 posts.Now I'm thinking it backs up my thoughts on CT and MRI scans.I've had many of both due to failed lower back surgery.I honestly believe that both have negatively contributed to the problems I have now.Can't walk more than 20 or so feet without being in extreme pain.I've had EDF since shortly after the surgery(maybe from the scans or surgery itself).I never have the energy I think I should at my age.I've recently been diagnosed with malignant melanoma(probably not connected but it makes one wonder).I feel agitated all the time.May or may not be connected.If I talk to my doctor about my concerns it just brings on more drugs and more tests.It makes me so tired I'm in the throws of giving up this machining business and going fishing.Gawd life's a bitch.BTW,I had hundreds of regular x-rays prior to the CT and MRIs.
 
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Diagnostic vs Therapeutic Xray

The OP was concerned with diagnostic x-rays. As threads are wont to do, this one is drifting off the original question.

Please note that the Therac devices were not used as *diagnostic* imaging devices but rather as cancer TREATING devices. They were *intended* to deliver carefully measured massive doses of radiation at levels thousands of times greater than any CT device or chest x-ray device. Those therapeutic radiation levels needed to be fine tuned as the margin of error between killing cancer cells and not the human subject him/herself is necessarily a fine line. So an error in that machine's software could result in severe adverse affects. That is a lot different than an error of similar percentage in a diagnostic machine where the margin of error between safety and injury is extremely great.

Denis
 
In addition to the prior concerns, radiation in general takes a considerable amount
of time to do its damage, assuming it is in the ranges mentioned as safe, ie under
50 mSv/year. The cancer risk requires decades to develop, so CTs done on
people in the 55yr and older types are less hazardous than CT scans done on children
or people under 30yrs old. This is a particular problem in a subgroup of young ladies
with chronic pelvic pain and or 'kidney stones'. Such can easily rack up 10-15 CT
scans of the abd/pelvis between the ages of 15 or so and 30 when for unclear
reasons the pains seem to abate. Throw in a few migraine headaches and chest
pain episodes with short of breath/hyperventilation and you add head CTs and
chest CTs to the mix.
 
Vraptors point on high voltage drift in CT scanners:

The high voltage supply in a CT scanner is regulated. Is the regulation perfect? NO. Does the minor variation that does exist mean anything to the patient? NO. Modern CT scanners perform regular self tests, in addition to regular human run testing. If there is a trend that the scanner detects, it will "phone home". Sometimes the service tech will show up, parts in hand, for a problem that has not yet sent the machine out of spec. The hospital may not yet know there is a developing problem.
 








 
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