Thyroid uptake test during breastfeeding

[Vasudha]

Hi,

I live in India and I took thyroid uptake test 36 hours ago. I was diagnosed for hyperthyroidism after delivery and I was on PTU medication since 4 weeks, 50mg twice a day.
Following are my concerns.

1. How long should I wait before I start feeding my baby again?
(Though I need to know when I can start feeding her again, I am not worried about this much as I have some stock in freezer and I also feed her formula, I do not mind waiting longer till I know it is absolutely safe to feed her)

2. I did not keep distance from my baby after uptake test. My doctor said it was not needed. I had called up Infant risk helpline today in the morning and I have been told that it is required to be away from baby for 20 hrs. I can be in the same room but not to hold her close. I am dead scared now thinking I might have caused harm to my baby.

111MBq or 3 mCi of Tc-99m was administered to me IV.

I want to know whether I may have caused any harm to my baby by not keeping distance from her? If yes, what is the possible harm ?.

I have been told that they will be confirming this to me via e-mail after consulting with Dr.Hale.
I thought of also posting it. My email id is mirji.vasudha@gmail.com

Please let me know.
Thanks,
Vasudha

[admin]

Vasuda:

First, most sources agree that there are no restrictions as for close contact with "Technetiium-99". As the doses goes much higher, one might want to be a little more careful holding and infant. In your case with a low dose (3 mCi), there is virtually no risk at all holding your infant.

As for breastfeeding, we are a little conservative and suggest that you refrain from breastfeeding for about 4-5 half-lives which means most all of the radiation is decayed away ( The half-life of Technetium is 6 hours. So 5 half-lives means 98% is decayed away).

But most importantly, you have not at all harmed your infant at all, as this radioisotope is really quite safe and is far less hazardous than any of the others we commonly use.

Tom Hale PH.d.