How worried should I be about CT scan radiation?

Dallas

New member
I'm 26, and had a CT scan last week. I've been reading about CT scans and all their radiation the last couple of days. How worried should I be? I've had two CT scans within a year and maybe one years ago, 3 MRIs, 3 or 4 ultrasounds and numerous X-rays. My grandmother died of bone cancer from radiation from X-rays.The MRIs, ultrasounds and X-rays have been spread out over years.
 

Tri

New member
Ummm, dear, bone cancer is not caused by X rays or X ray radiation. Radiation is actually used to treat bone cancer. Bone cancer is caused my immature bone marrow cells rapidly proliferating (growing out of control) and crowding the bone space. That causes the inside of the bone to become packed with so many cells that the pressure becomes unbearable and causes great pain. The immature cells (bad cells) crowd out the mature cells (good cells) until the person no longer has the cells needed to maintain life... causing death. I know the media makes us think cell phones, x rays, radios, tvs, etc automatically cause cancer. But those are people that don't know the breakdown of cancer. Radiation is used to treat cancer. Side of effects of radiation are weakness, radiation burns, skin / tissue death due to the burns, things of that sort. Of course we must protect ourselves from large amounts of radiation because of those side effects. That's why pregnant people aren't allowed to have X rays or be near radiation, the power of it can kill a developing baby, because the baby is basically new tissue. I don't think any dr will ever say, "Your cancer was caused by X rays". If that was the case, X ray techs, drs and nurses would all be dead from cancer caused by X rays. Don't worry about getting cancer from exposure to that kind of radiation. It's harmless unless you are a developing fetus.Think about it, why would one treat cancer with the cause of cancer (if it was radiation)? That would be like feeding someone bacteria to cure an infection. Wouldn't make a lot of sense.
 

Elliot Y

New member
I am sorry, but Tri, who asked (paraphrased) "Why would doctors treat cancer with something that causes cancer?" is quite incorrect with her answer. The answer to her question is "Why indeed?" CERTAINLY chemotherapy is carcinogenic, and so is radiation! The answer is that doctors treat cancer with cancer-causing treatments because they don't know of anything else to do and because it makes them money. I was diagnosed with cancer in 1989, and another oncology nurse, (not Tri), said to me "If YOU don't take control of your OWN treatment, the doctors will turn you into a PIECE OF MEAT." The American Cancer Society says that a whole body CT Scan exposes a person to as much radiation as some of the survivors of the Hiroshima/Nagasaki bombings! CHILDREN ESPECIALLY should be protected from ALL but ABSOLUTELY NECESSARY CT scans! It's a shame, but there are many, many misinformed medical personnel like Tri. She means well, but she is dangerously misinformed.
 

rudy

New member
Hello, and good question! The short answer is that your risk of getting cancer from the radiation you received from your tests is VERY low - but not zero. If you are having health issues requiring the tests, you should not at all be worried about receiving the tests, because the benefits of figuring out what is going on is MUCH greater than your cancer risk.Up front, I should also mention that neither MRIs or ultrasounds have any ionizing radiation in them, and therefore do not cause any cancers.X-rays and CT-scans do give the patients who receive them some radiation, however the dose is typically quite low. How low depends upon where you are scanning and how many scans you've had done. The doses used to quantify the radiation an individual receives can be a bit confusing, but the best measure to use when considering that risk of getting a cancer secondary to the radiation is the "effective dose" which is measured in Sieverts - or milliSieverts (mSv = 1/1000 of a Sv). The best estimates of cancer risk from radiation is estimated to be abotu 4-5% per Sievert received.To put this in perspective, a typical chest X-ray results in an effective dose of about 0.1mSv while an abdominal CT is considered to give "a lot" of radiation or about 8-10mSv. Using the risk estimate of 4-5%/Sv, this means a CXR increases your risk of getting cancer by 0.000 5% (5 per million) and an abdo CT increases the risk by 0.05% - or 5 per 10000. A few more important points bear mentioning:1. Overall an individuals baseline risk of developing cancer (i.e. the risk everyone has just by being alive) is much greater than that due to any radiation received from x-rays. (And the risk of cancer from smoking is so much greater than any you get from radiation: ~1% of cancers are caused by radiation exposure, whereas ~40% of cancers are cause by smoking.)2. For those who get cancers from radiation exposure, these take at LEAST 10 years to form and typically develop 15-30 years after.3. The risk of developing cancer following radiation also depends upon the age when the radiation/x-rays were received. The risk is highest in individuals who receive radiation as children, with moderate risks for those in early adulthood. The risks are negligible for those over 50 years. To put this in perspective, though, in the higest risk cases whereby children ~10years old receive radiation to treat cancer we typically treat to doses 2000x that which you receive with a CT scan. This is thought to cause a lifetime risk of cancers in the neighbourhood of 10-20%. In your case, you are an adult and the doses you receive with your diagnostic tests are much smaller, so your risk is almost negligible.I hope that this helps.
 
There is no doubt that high doses of radiation cause cancer. This is seen in survivors of nuclear explosions and in people receiving radiotherapy. In the past radiologists who exposed their hands to radiation often died of cancer.The problem is that there is no measurable effect from doses used in radiology. The risk is worked out from extrapolating the effect at higher doses. The dose you receive from CT depends on a number of factors including your size, the scanner used and the region of your body scanned. The dose from a CT of abdomen and pelvis is about 500 times a chest XR. The doses are thought to be cummulative so it doesn't matter if you have two scans a day apart or 10 years apart. The risk of inducing a fatal malignancy for a single abdo scan was until recently guestimated as 1/2000 but now this has been revised to 1/1000. Radiation induced cancer takes 15-20 years to develop so this is more important in young people. For the elderly where the potential benefits are greater the risk from CT is probably overstated.You should avoid CT unless there is no alternative. In many cases MRI or US can be used for follow up and these are harmless.
 
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