Dr. Andrew Chellakumar Fenn
Radiation Oncology
The following is an actual conversation between an iCliniq user and a doctor that has been reviewed and published as a Premium Q&A.
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Patient's Query
Hello doctor,
I am 29-years-old and in good health. My height is 6 feet and 1 inch, and I weigh 165 lbs. I just had a CT scan around my stomach for kidney stones. This is the second scan in the same area. The first was a 3.86 mSv dosage, and the second was a 3.26 mSv dosage. Should I be worried about cancer from radiation? I heard the body heals itself from slight radiation like this. Is that true? How much is too much? This was all in the same year and a head CT scan. I have had a total of three CT scans in the previous year. Other tests which I have taken a blood test and urine test.
Hi,
Welcome to icliniq.com.
You do not worry about the radiation dose from regular computed tomography (CT) scans done to diagnose disease. You do not need to worry about CT scans done for diagnosis as these have benefits beyond any potential or perceived detrimental effects of radiation. The general public's whole-body radiation dose acceptable limit is 5.0 mSv annually. For a radiation worker, it is 50 mSv. You must understand that the radiation is being given through a CT to diagnose and treat the disease. Magnetic resonance imaging (MRI) may not be a good option for kidney stones. So it is within reason to have these scans and not worry about any potential cancer that may or may not happen in 20 years.
Patient's Query
Hello doctor,
I am confused here because you said that the dose acceptable for the general public is 5.0 mSv annually, but I had about nine this year with two CT scans for the stomach and one for the head. That is why I am worried. You said not to worry because the CT scan for diagnosis outweighs the effects of the radiation. While that is true, I have nothing to worry about now but the radiation since nothing was wrong with me. I am just worried that 9.0 mSv is a lot, and it will give me cancer.
Hi,
Welcome back to icliniq.com.
Did I mention that for a radiation worker, it is 50 mSv. It does not mean that you will get cancer once you cross 5.0 mSv. Even 50 mSv is not a high risk for cancer. It means that you need to be a little careful when you go for your following scan. Avoid it if the same diagnostic information can be obtained through ultrasonography or magnetic resonance imaging (MRI), but if computed tomography (CT) is only available and if important diagnostic information will be missed, your best bet is still a CT. When it comes to radiation, dose limits are assigned low so that remedial action can be taken, not to determine cancer occurrence. Even if you receive 1 mSv a year which is the background radiation from space, you are theoretically at risk of cancer. But the chance of it happening increases with increasing dose. So my advice is not to worry, and if you are advised a CT scan, schedule a meeting with your doctor or radiologist to determine the need to do the same and if any alternate tests could be done.
Patient's Query
Hello doctor,
Thank you for that. Then why does everyone freak out about CT scans and cancer? Also, do you know of any foods that can reduce DNA damage? I read that blueberries can help with that.
Thank you.
Hi,
Welcome back to icliniq.com.
Any foods with high anti-oxidant activities will be good against deoxyribonucleic acid (DNA) damage. All fruits and vegetables are good. Healthy exercise daily or thrice a week stimulates the body's repair mechanisms. Low fat, low alcohol, and no smoking are prescriptions for a healthy life. We have a principle in radiation called (ALARA) as low as reasonably achievable. So that is why it is low for the general public and higher for radiation workers, but the basic principle is to keep the dose as low as possible as even 1.0 mSv can give you cancer, but it is not reasonable to limit it 1.0 mSv.
Patient's Query
Hello doctor,
So I have no increased risk of cancer with two CT scans to the stomach and one to the head?
Hi,
Welcome back to icliniq.com.
Not really. As I said, the benefits outweigh any potential risk.
Patient's Query
Hello doctor,
I know they outweigh the risk, but they found nothing; that is why I am focusing on the radiation. Do you know how much of an increased risk I got? I read somewhere that a 10.0 mSv will only raise your chances by 0.05 %. Is that true? Total, I believe I am only at 9.0 mSv, which I am sure is nothing when you said radiation workers could get 50 a year. If I eat foods rich in antioxidants and work out, will that help counter this damage?
Hi,
Welcome back to icliniq.com.
Yes. The 0.05 percent risk is true. And the diet and exercise should help.
Patient's Query
Hello doctor,
I have a few questions; Is there a balancing where if I get 9.0 mSv this year, then I get much lower over the next couple of years? Does it average out? Can you reverse the damage from diet and exercise caused by radiation? Can your body heal low doses of radiation? If so, what are low doses? Does it matter whether you get one scan that is 10.0 mSv or two 5.0 mSv? Are they the same or different?
Thank you.
Hi,
Welcome back to icliniq.com.
Yes, the risk does average out. Yes, the damage can be reversed but to what extent is an area of controversy. Yes, the body can heal itself over the years. People are not dying of the one to two mSv background radiation around us. There is no low dose. ALARA (As low as reasonably achievable) is the principle that is followed. A 10.0 mSv scan may have more cancer risk than a 2.5 mSv scan, but the risk is unimaginably tiny that I would not let my head spin over it.
Patient's Query
Hello doctor,
I was specifically worried about leukemia because I used to smoke half a pack a day from 19 to 26 years old (3.5 total pack-years), and then I got these three scans in a year. Should I be worried? I quit smoking three years ago and live a healthy lifestyle now.
Hi,
Welcome back to icliniq.com.
Do not really know for sure. Considering that 40 pack-years is the cut off for screening for lung cancer. But even one cigarette can cause lung cancer theoretically. So keep your healthy lifestyle and follow up any symptoms which you feel are suspicious.
Patient's Query
Hello doctor,
Should I be worried?
Hi,
Welcome back to icliniq.com.
No, I do not think so.
Patient's Query
Hello doctor,
I have a question that I do not know if you know the answer to, but I will ask anyway. If not, that is fine. As I told you before, I smoked 3.5 pack-years total. I quit smoking three years ago, and I am 29. Well, my great-grandmother died from lung cancer at 49. She was a very, very heavy smoker, and so was her husband. Does her dying early increase my risk of getting lung cancer, or does it not matter because she smoked super heavily, and that was several generations ago? Her daughter (my grandfather's sister) is in her 70s and has COPD. She was also a lifelong smoker. Should I be worried even though I have 3.5 pack-years? I did not know if genetics were still a factor when it was several generations ago.
Hi,
Welcome back to icliniq.com.
They say that genetics loads the gun, and the environment is the trigger to most diseases, cancer being no exception. I have seen long-time smokers with no cancer, and I have seen short-time smokers or non-smokers with aggressive forms of the disease. We do not know a lot, but we do know a few things. Smoking predisposes individuals to cancer. This could be self, passive, or even environmental. But each person's inherent genetic susceptibility will determine if you get the disease or not. In your case, it is quite apparent that there seems to be some genetic susceptibility, but the insult that the body endured in both instances was severe. I am unsure if this could mean that you will develop cancer in the future. My advice would be to eat healthily, avoid junk foods, and exercise. I would also advise you to meet a lung specialist and take his advice on screening for lung cancer as I am currently unaware of the latest in that field.
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Radiation Oncology
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