Re: radiopharmaceutical patient release

["CAPT J. A. Thomas" <jathomas@radlinux1.usuf1.usuhs.mil>]

Generally, we treat Graves disease with 3 to 7 mCi.  150 mCi is a
therapeutic dose used for Rx of Thyroid Carcinoma.  In the first case
(graves disease) the patient has an intact thyroid gland.  The intent of
the Rx is to oblate the thyroid gland.  A general rule of thumb is that the
dose to they thyroid gland is 1 rad per microcurie taken up by the thyroid.
 NOTE:  This is not per microcurie administered to the patient.  If I
remember correctly, the uptake should be between 25 - 40%. In the second
case (thyroid carcinoma) most all (e.g. all visible) thyroid tissue is
surgically removed, thus the need for larger amounts of I-131.

	Patients with whom I have had involvement with their Rx have always
received instruction wrt what they can and can not do....e.g. air travel,
auto travel, how close they can be to young children, where and with whom
they can sleep ... etc.  

	The case Kent Lambert describes must be that of a person that was
hopitalized for Rx of Thyroid Carcinoma and NOT Graves Disease.  I would
believe that 8 hours following administration 0f 150 mCi that a patient
could vomit 1 mCi.  But, the patient is in the hospital.  Release limits
require that the patient have a total activity of less than 30 mCi at the
time of release.  That is why you will see many prescriptions written for
29.9 mCi.  Then there is no legal need to hospitalize the patient.

JERRY THOMAS


At 11:43 02/12/97 -0600, you wrote:
>Kent Lambert wrote:
>
>> 
>> If a patient is treated as a outpatient for Graves disease, gets on an
>> airplane, and gets airsick, then a significant amount of I-131 can be in
>> the vomitus.  I have measured 1 mCi out (of a 150 mCi administration) in
>> the vomitus from a patient that got sick 8 hours post administration.
>> What's the dose rate to the skin from this?  Assuming 1 mCi on 100 cm^2
>> it's 63 rad/h of contact time.  That results in erythema in 5 hours of
>> contact time.  Without instructions, how is someone to know that careful
>> and prompt washing (or removal of contaminated cloting) is important?
>
>I can't believe that anyone would leave vomitus from another person or
>from themselves on their clothing or body for any significant length of
>time.  It stinks too much, particularly on an airplane.  I was sitting
>next to a little girl who upchucked during rough weather.  The cabin
>attendant was very prompt in cleaning up the mess, including the little
>girl's dress.  Also, I don't believe that patients with 150 mCi of I-131
>are permitted to leave the medical facility.  The number that sticks in
>my mind is 30 mCi.  So the dose rate would be about 15 rad/h of contact
>time in your example.  Then it would take about 25 hours to get the dose
>that someone might consider significant from the non-stocastic, skin
>standpoint.
>
>Also, I believe that patients are given instructions on how to behave
>after treatment so that doses to others are not a problem.  I assume
>that such instructions include what to do upon upchucking.
>Al Tschaeche xat@inel.gov
>