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Re: medical misadministration to child
Is the MIRD dose factor for normal thyroid uptake. If the patient was being
scanned because of a suspected hyperthyroid condition, it seems that the uptake
and dose would be higher.
Second question. Would prompt intervention, eg, administration of stable iodide
have been effective in reducing the dose?
It seems that even late intervention would be helpful in reducing the dose from
recycled iodine.
The opinions expressed are strictly mine.
It's not about dose, it's about trust.
Curies forever.
"North, David" wrote:
> Not being a reactor-type guy, I am not familiar with Reg Guide 1.109.
> However, the MIRD Dose Estimate Report No. 5 shows that for I-131 the
> thyroid receives roughly 1 rad for every uCi administered orally to an
> adult. Doubling that figure because the child's thyroid is probably about
> half the size of an adult's gives about 800 rads, less but still a lot. The
> thyroid is a pretty resistant tissue, especially for acute, nonstochastic
> effects. Usually several thousand rads are needed to treat a hyperactive
> gland, which is a standard medical practice. A progression to hypothyroidism
> tends to occur over a number of years afterward. Nevertheless, I am also
> puzzled that the hospital can bluntly assert that no "adverse health effect"
> is expected after 800 rads.
>
> David L. North, Sc.M., DABR
> Medical Physics
> Main Bldg Rm 317
> Rhode Island Hospital
> 593 Eddy St.
> Providence, RI 02903
> (401)444-5961
> dnorth@lifespan.org
>
>
> > ----------
> > From: William V Lipton
> > Reply To: William V Lipton
> > Sent: 4, April 2003 10:08
> > To: radsafe@list.vanderbilt.edu
> > Subject: medical misadministration to child
> >
> > Please see the NRC event report that I pasted, below. A 9 year old
> > patient who was in for a thyroid diagnostic scan was supposed to receive
> > 4 uCi. Instead, he (she) received 400 uCi. The cause is stated as,
> > "The wrong dosage was ordered from the radiopharmacy." It seems as if
> > the dose rate should have warned them that something was wrong.
> >
> > I'm curious about the statement, "The hospital indicated they did not
> > expect any significant adverse health effect." Table E-13, of NRC
> > Regulatory Guide 1.109, "Calculation of Annual Doses to Man From Routine
> > Releases of Reactor Effluents ..." lists a dose factor, for a child
> > thyroid for I-131 ingestion, of 5.72 E-3 mrem/pCi ingested.
> >
> > Thus, the dose estimate would be:
> >
> > (5.72 E-3 mrem/pCi)*(400 uCi)*(1 E6 pCi/uCi) = 2.3 E6 mrems = 2300 rems
> >
> >
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