Hello Cassandra,
isotopes used in PET scans have short half lives: carbon-11 (20.39min),
nitrogen-13 (9.96min), oxygen-15 (122.24sec) and fluorine-18 (110 min) These
short half lives are the reason why they have to be made close to the place
where the PET will be performed (only fluorine-18 can be manufactured
somewhere else and transported).

I have been unable to find indications specific for these radioisotopes (NRC
and Dr Hale give waiting times for other radioisotopes but not for PET) but
given the short half lives and low activities involved, 3 days (which would
amount to 40 half lives for fluorine-18 if my math is OK) is way too
conservative. Radioisotopes in the body have the contribution of the
metabolism which in many cases reduces the time the radioisotope remains in
the body. Recommendatns for Tc99m are 6-24 hs depending on the
radiopharmaceutical involved.

I would ask the nuclear medicine specialist for references to support these
three days of pumping and dumping. It seems to be excessive.

Veronica Garea ME Nuc Eng, PhD Engineering Physics - Nuclear Safety
Specialist


>  4. PET scan
> Date:    Sat, 30 Aug 2008 13:14:29 -0400
> From:    Cassandra Leahy <[log in to unmask]>
> Subject: PET scan
>
> I am working with a mother who is scheduled for a PET scan next week=20
> and I want to clarify/check the instructions she received to "discard=20
> expressed milk for 3 days".  I do not have access to my reference books=20=
>
> and I was unable to find the information in archives.  If anyone has=20
> information on PET scans and breastfeeding I would greatly appreciate=20
> it.
>
> Thank you,=20
>
> Casi Leahy
> BA, RN, MSN, LCCE, IBCLC
>
>
-- 
Verónica Garea
GALM Bariloche
IBFAN Bariloche - LLL Argentina
"Es más difícil desintegrar un prejuicio que un átomo / It is harder to
crack a prejudice than an atom"
Albert Einstein



-- 
Verónica Garea
GALM Bariloche
IBFAN Bariloche - LLL Argentina
"Es más difícil desintegrar un prejuicio que un átomo / It is harder to
crack a prejudice than an atom"
Albert Einstein

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