Radiology/CT scan dose



Recently I've made a chest CT scan and unfortunately radiologist didn't tell me the effective dose, she just said that the scanner was modern (Toshiba aquilion 128, year 2008) and my dose was approximately about 2-3 mSv (I am 55 kg 165 cm). I also unsed to smoke for about 7 years. I am 23 y.o. Now I am very afraid after reading all this material via internet about how dangerous CT is, even a single one. The thing is that there was particularly no need in that scan and I feel very sorry that I've got it. Could you please tell me is a single scan really that dangerous?  I am very scared. I also want to have children in a year (but I am not pregnant now). CT resaults claimed I am absolutely healthy.

ANSWER: Tatiana,

I can assure you that you did not do any harm to your body.  The things on the internet are blown out of proportion especially for regular people who do not quite understand physics and radiation.  If you fly on an airplane for 4 hours you also get radiation equal that of a chest xray (not CT but still).  We get yearly doses of radiation from various sources.  Chest CT is nothing that would add any substantial risk to cancer or other health related problems.  You are fine with pregnancies and so on.  Relax and enjoy!

Misha :)

---------- FOLLOW-UP ----------

QUESTION: Dear Misha,
I just came up with some thoughts, and I think maybe this information can be helpful for other people concerned about ct scans since there are some..
My radiologist too said that the risk is very very low.  From what I read for woman the risk is considered about 1 in 1000. It is stated that the younger the woman is the riskier it is. From what I studied it is said thatsuch a disease as cancer takes years to develop. So my questions are:
1)does it mean that after any, even single ct scan cancer starts developing due to DNA damage? If not, then how can we understand this assumption (...takes years to develop)?
2)can this statistics (1in 1000)be applied to ones who had a single chest ct scan (effective dose as doctor said is approximately about 3 msv) Some sources say even that up to the age of 40 chances become 1 in 80 already!!How can it be?
3) Are risks lower today since we have modern scanners with AIDR 3D, iDose? Statistics were taken from people who got cts 2003-2007 (I don't know if these functions were performed those years)
4) I am hypothyroid. Does it matter concerning risks? (Ct was without contrast)
5) Since I have smoking history, and for some time used to smoke one cigarette a day after ct,( I do not anymore)should I be too much concerned that cigarette a day harmed me twice as much after ct? I'm very afraid to continue and feel sad and ashamed I smoked after 4 months break
I was almost in panic when I wrote my first question, now I'm not already, maybe due to your consoling reply,  however I think about it sometimes and maybe feel uneasy at some points...of what I read on the net, your answeres are quite full and helpful, but I haven't seen any questions like mine in here...
I would feel very, very grateful if you could provide me with answeres!! Thank you very much.


Firstly, cigarettes do not make radiation more harmful or vice the risk of lung cancer from smoking has no relationship to the CT scan and its radiation.

There is a site you can visit - calculate your increased risk.. I actually did that for you.  for a 23 year old woman with a single low dose CT of the chest with an affective dose of 2 mSv  you additional risk is 0.033%  (1 in 2954 people)
your base line risk for cancer without any CTs  is 37.5% just by being a living human being...unfortunately we will all die (sorry)  and unless it is an accident, then two causes of death will be heart attacks, strokes from old diseased blood vessels or cancer...

Our DNA constantly makes mistakes and our body constantly tries to repair these mistakes, quite successfully so we get to live to an old age....

In reality, statistics are great for a population but not really for an individual...most of major knowledge on radiation exposure comes from Hiroshima explosion.  You can certainly agree that this data by any means is refined...but this is all we got. Yes later studies try to make better estimates but the reality of it is that it is a general gestault and approximation.

Want to reduce your risk of cancer?  drink water, eat right, run/swim...and yes don't smoke...the rest really doesn't matter

Hope it helps.  



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Michael K.


Almost any kind of questions regarding any types of radiology exams, procedures, meaning of radiology reports etc...


12 year experience in the field of radiology

American Society of Neuroradiology, Senior Member Society of Pediatric Radiology, Active Member

Radiology Seminars in pediatric neurology American Journal of Roentgenology American Journal of Neuroradiology

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