RE: medical misadministration to child

["North, David" <DNorth@LIFESPAN.ORG>]

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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