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Joined: Jun 2012

I had to get a small dose of 2-4 mCi for a scan. I was just wondering if anyone knows what the breakdown of it would be in hours/days. Would it be safe to go for a blood test after only about 36-48 hours? I have been drinking a lot and using the bathroom more then once per hour at times to get it out of my system but I'm still unsure and does it even go out faster the more you urinate?

Posts: 582
Joined: Oct 2010

Your dose was very small. You aren't dangerous to anything and neither is your blood. I will put it in perspective for you. I had a scan dose of about 6 mCi's and was around my family and pets right after. I had a couple of treatment doses of 175 mCi's and I had to isolate for a minimum of three days. After three days I kept a ten foot radius from other living things. After seven days I was clean. Yes, it clears out faster when you drink and urinate. RAI has a half life. So, twenty-four hours after you take it, it is half of the original strength. In another twenty-four hours it is half of half the original strength and so on. I hope this helps.


Baldy's picture
Posts: 243
Joined: Mar 2011

Most likely you recieved a dose of Iodine-123 for your scan. As Julie says, there's no need to worry about it. It's half life is aproximately 13.3 hours and it decays benignly by electron capture. It decays to Tellurium-123 which is extremely slowly radioactive and a benign substance, it's called "metastable" which means it's half life is so long it's stable for all practical purposes. I've had two I-123 scans so far and each time they've assured me I don't need to take any precautions whatsoever. Also, as Julie points out, you lose almost all {99%} of any radioactive Iodine they give you in the first 24 hours through urination, which is why they tell men to urinate sitting down after getting an ablation dose of I-131 for the first few days.


Posts: 2
Joined: Jul 2012

I had it before my scan is not going to be a serious one:)
just to help you not to expose to much from radiation when you get your scan.
The one you should worry is the I-131 and it depends on how much you will get.I had I-131 just couple
days ago still in my isolation inside my house.So far I didn't feel sick or anything just being sleepy the first 2 days
I didnt do anything extreme at all just relaxing. and hopeful that soon I will be better
don't worry about it .

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