What does radiation do?
Desiree McCrorey
started hinting, after only treating me for a few months with Tapazole,
that I should consider radiation or surgery.
Most of the time, I'd rather not consider anything but medication. There
are times, though, when I've this sense of something really tightening
around my throat.
Naturally surgery isn't an attractive option. So that leaves radiation.
But I would like to know specifically what radiation does to the thyroid.
I really don't like the thought of a large dead thing wrapped around my
trachea.
Does anyone here know of a source of info on what radiation does? I've
already got Harrison's Internal Med, but even this reference doesn't go
into enough detail.
Thanks in advance,
Desiree
Kevin G. Rhoads
radioactive elements when they decay. Before it was
known what they were they were labeled
alpha, beta and gamma.
We now know alpha are Helium nucleuses (big, heavy, slow)
beta are electrons (light, fast)
and gamma are electromagnetic (like X rays but more so)
Alpha will not penetrate skin, so an alpha emitter OUTSIDE
the body is harmless. But if you get it inside, then it can damage
or kill tissue BIG TIME.
Gamma will penetrate, but what makes it able to penetrate also
means it is unlikely to do anything. You need massive amounts
of gamma to do tissue damage.
Beta is in between. More penetrant and less damaging than alpha,
less penetrant and more damaging that gamma.
In the radioactive iodine treatment, a radioactive form of iodine
is ingested. Since the thyroid concentrates iodine, it normally
ends up there. If a gamma emitting RAI is used, you "light up"
the thyroid for diagnostics, but at the low amounts used, no
appreciable tissue damage is done. For RAI thyroid destruction
a different RAI is used, either a beta or an alpha emitter. SO
a small amount will do lots of damage to the thyroid gland.
The RAI decays fast. But the killed thyroid tissue remains for
a bit until the body resorbs it. (How fast does a "back and blue"
fade away on you? Same process will resorb the killed thyroid
tissue, takes a bit longer though.)
If you have Grave's eye disease, note that RAI has higher
incidence of eye complications than surgical removal of
the gland. However, surgery has many complications
also - vocal cord and/or parathyroid damage, scarring.
And for many people control by thyroid suppressant drugs
works well.
Now if this is not technical enough, I can go into linear
energy transfer and momentum vs. energy issues. Tissue
damage mechanisms by free radical formation (only that
is more Ted's area than mine) and ionizing radiation. But
I expect that is not what you are interested in. If you
are, just ask. But I tried to present the major issues without
so much technical gobbledegook.
--
Kevin G. Rhoads, Ph.D. (Linearity is a convenient fiction.)
T_Rhoads@NO_SPAM.MSN.com
krhoads@NO_SPAM.cmpnetmail.com
Joan K. Ryan
T3. If so, T3 is moves to the nucleus of every cell and acts to unwind
the DNA so that all of our genes can replicate. My concern is that RAI
is an excellent delivery system of radioactivity to our DNA.
Anybody have any thoughts on this?
Nick
<joan...@ziplink.net> wrote:
>Kevin. Do you know if any of the radioactive iodine combines to form
>T3. If so, T3 is moves to the nucleus of every cell and acts to unwind
>the DNA so that all of our genes can replicate. My concern is that RAI
>is an excellent delivery system of radioactivity to our DNA.
>Anybody have any thoughts on this?
An interesting thought, I don't know the answer but it would concern
me.
Nick
--
Warning, I am not a Doctor, If you are thinking of making any changes to your medication discuss it with your doctor first.
Check these sites for good information on thyroid problems
http://www.personal.u-net.com/~my4tune/appto_treatment.txt
http://www.personal.u-net.com/~my4tune/itg.htm
http://thyroid.miningco.com/
Kevin G. Rhoads
> to form T3.
RAI will be incorporated into both T3 and T4.
The real issues here are two:
1)the relative rates of RAI decay versus the gland's incorporation and
subsequent transport to metabolizing cells -- the RAI used for
killing the gland has a fairly rapid decay -- how fast the RAI can move
"through" the gland needs to be compared to the half life of the RAI
(I don't have numbers for these immediately available to me, also
there seems a lot of variability in the numbers for physiological
processes -- while the RAI half life is a well determined number,
the time constant for iodine to T3/T4 may vary quite a bit from
person to person.)
2) the concentration/dilution factor -- the RAI is concentrated in the
gland since the gland collects iodine, whereas radioactive T4 and T3
will be diluted by the pre-existing (if any) stores of non-radioactive T3
and T4 [the usual course of running out any thyroid hormone stores before
administering RAI probably makes this moot -- it suggests that a large dose
of T4 administered SIMULTANEOUSLY with the RAI may be a
REALLY GOOD IDEA -- if we all start yelling about this now, the
nuclear medicine people may actually look into it in this decade]
> My concern is that RAI
>is an excellent delivery system of radioactivity to our DNA.
I think this is just one of those issues that is ignored because the
question never occured to anyone (in nuclear medicine) to ask.
Where the heck is Steve Crisp when you need him? This would be
a great set of questions to dump on the NIH people . . .
BL 1204
>a great set of questions to dump on the NIH people . . .
>--
ROFL!! I bet he is practicing his meditation on a mountaintop in Tibet! BL
Robin
BL 1204 wrote in message <19981229150425...@ng26.aol.com>...
I'll join him on this thought. in Tibet
Robin
RAI'ed a year ago and don't need to worry about it since I can't do anything
about it :) But the Future is a wonder thing
Alan Goodman
<T_Rh...@NoSpam.CLASSIC.MSN.COM> wrote:
>> Do you know if any of the radioactive iodine combines
>> to form T3.
>Assuming the thyroid gland is functioning, then YES --
>RAI will be incorporated into both T3 and T4.
>
>The real issues here are two:
>1)the relative rates of RAI decay versus the gland's incorporation and
>subsequent transport to metabolizing cells -- the RAI used for
>killing the gland has a fairly rapid decay -- how fast the RAI can move
>"through" the gland needs to be compared to the half life of the RAI
>(I don't have numbers for these immediately available to me, also
>there seems a lot of variability in the numbers for physiological
>processes -- while the RAI half life is a well determined number,
>the time constant for iodine to T3/T4 may vary quite a bit from
>person to person.)
Nuclear half life for I131 is about 8 days - constant.
Physiological half life for T4 is about 7 days.
Physiological l half life for T3 is about 1 day.
Physiological for I131 (or any other Iodine) in the body is about 1/2 day.
Most of this is lost by peeing, sweating and salivating.
Physiological half lifes are variable by person.
>
>2) the concentration/dilution factor -- the RAI is concentrated in the
>gland since the gland collects iodine, whereas radioactive T4 and T3
>will be diluted by the pre-existing (if any) stores of non-radioactive T3
>and T4 [the usual course of running out any thyroid hormone stores before
>administering RAI probably makes this moot -- it suggests that a large dose
>of T4 administered SIMULTANEOUSLY with the RAI may be a
>REALLY GOOD IDEA -- if we all start yelling about this now, the
>nuclear medicine people may actually look into it in this decade]
A goodly dose of I131 (say 100 mCi) is contained in 1 mgr of I131. Compare
this with the RDA of about 150mgr of normal iodine or the average measured
daily input of about 450mgr of normal Iodine.
I don't have the numbers for the noraml amount of Iodine in the body - but
it is a lot more than the RDA.
>> My concern is that RAI
>>is an excellent delivery system of radioactivity to our DNA.
>I think this is just one of those issues that is ignored because the
>question never occured to anyone (in nuclear medicine) to ask.
>
>Where the heck is Steve Crisp when you need him? This would be
>a great set of questions to dump on the NIH people . . .
Alan
===
The statement below is true.
The statement above is false.
Joan K. Ryan
unwinding the DNA? Or, in other words, is RAI an excellent delvery
system of radiation to our genes?
There's a hot question!