- Re: Re: RAI treatment

[Guest guest]

Hi, -

I agree with Judith; I think there is some misunderstanding regarding your

RAI doses.

> Yes, I may be getting three.

Not in such short order.

> Perhaps that's why the first tracer

> dose is only 5 microcuries.

Tracer doses are almost always 2-5 mCi; any higher risks " stunning " , which

can block uptake of the therapeutic dose.

> I may be getting some of the details

> wrong, but it's my understanding that they use the first dose to

> check and see if there is a bunch of thyroid tissue still left in my

> neck.

It's almost guaranteed that there will be some; hopefully not a lot.

> The idea being that if the surgeon didn't do his job very well

> and left a bunch of the thyroid there, they don't want to do the RAI

they'll do it, but they'll do a lower dose (usually maximum of 30 mCi)

> (perhaps they've found problems with folks who've had this happen).

If there is too large a remnant, a high dose of RAI (> 30 mCi) can cause

radiation thyroiditis.

It's almost unheard of to have NO thyroid cells remaining after a TT; my

analogy is that it's like trying to remove the red part of a watermelon

without touching the white part (in this case, important parts of the

anatomy, such as the larynx, etc.). It's much safer to leave small

amounts and have them ablated with RAI.

Of course, a poor surgeon could leave too much, but they all leave some.

> If there isn't a bunch of thyroid, they then give me an outpatient

> dose of RAI at 30 millicuries, then I go home for isolation. After a

> few days I go in for another scan, and I think they said that,

> depending on that scan, I may or may not be admitted to the hospital

> immediately after the scan. I think the second scan is looking for

> any signs of the cells spreading beyond the neck. If they find any,

> then they admit me and do the third dose in the 100-200 millicurie

> range, the amount depending on the scan results. If none is found, I

> may get to skip the inpatient treatment.

This is the part that I think got confused in the translation.

After the ablative dose (sometimes 4 days later, sometimes 7, sometimes

both), another scan is done, taking advantage of the higher level of RAI in

your system, and possibly revealing metastases that didn't show up with the

lower scanning dose.

However, if they DO find extensive mets or spreading beyond the neck in the

post ablation scan, they will definitely give you a higher dose, but not

until at least 6 months or so. Your thyroid cells will already be

saturated with the 30 mCi dose, and giving a larger dose too soon would be

a waste of time and radioactive sludge.

In any case, you will most likely have another RAI scan in 6-12 months,

using the information from the post ablation scan, plus another scan dose

of 2-5 mCi, which will indicate whether or not another ablative dose is

required at that time.

Make sense?

-

(not a doctor)

NYC

TT 2/99 dx pap/foll; RAI 100 mCi 3/99 & 4/00; clean scan 3/02;

current TSH ~.06 on .225 levothyroxine