Re: saftey of being in the proximity of someone on RAI therapy

[John Jacobus <crispy_bird@YAHOO.COM>]

You may have missed my point.  Most of the elimination

of unbound I-131 occurs in the first day following

adminstration of the dose.  That is why you treat an

ablation patient inhouse before you release them.  At

home, the contamination levels are a small fraction of

those you find in the patient's room.



The following may be of interest:



----------

"Radiation exposure from outpatient radioactive iodine

(131I) therapy for thyroid carcinoma."



Grigsby PW, Siegel BA, Baker S, Eichling JO.

JAMA. 2000 May 3;283(17):2272-4. 



CONTEXT: In May 1997, the US Nuclear Regulatory

Commission (NRC) revised its patient release

regulations, allowing for outpatient administration of

larger activities of sodium iodide 131I than

previously permitted. OBJECTIVE: To measure the

radiation exposure to household members from patients

receiving outpatient 131I therapy for thyroid

carcinoma in accordance with the new regulations.

DESIGN: Consecutive case series from October 1998 to

June 1999. SETTING AND PATIENTS: Thirty patients who

received outpatient 131I therapy following

thyroidectomy for differentiated thyroid carcinoma

were enrolled, along with their 65 household members

and 17 household pets. MAIN OUTCOME MEASURE: Radiation

exposure to household members and 4 rooms in each

home, as monitored with dosimeters for 10 days

following 131I administration. RESULTS: The patients

received 131I doses ranging from 2.8 to 5.6 GBq (mean,

4.3 GBq). The radiation dose to 65 household members

ranged from 0.01 mSv to 1.09 mSv (mean, 0.24 mSv). The

dose to 17 household pets ranged from 0.02 mSv to 1.11

mSv (mean, 0.37 mSv). The mean dose to the 4 rooms

ranged from 0.17 mSv (kitchen) to 0.58 mSv (bedroom).

CONCLUSION: In our study, 131I doses to household

members of patients receiving outpatient 131I therapy

were well below the limit (5.0 mSv) mandated by

current NRC regulations.

----------------

"Internal exposure to relatives of radioiodine therapy

patients from I-131 inhalation at home"



W. Eschner, U. Wellner, H.-W. Hillger and H. Schicha 



SUMMARY: We studied the exposure to relatives of

radioiodine therapy (RIT) patients from inhalation of

131I exhaled by the patients at home after their

discharge from the hospital. Whole-body 131I activity

was measured in 17 volunteers, all relatives of

patients who had undergone RIT for benign thyroid

disease, a few days after the patients' discharge. In

9 out of these, thyroidal 131I activity was measured,

too. The measured activity was compared with the

result of calculations based on a three-compartment

model of iodine kinetics. A good correlation (r =

0,88) was established between measured and predicted

thyroidal activities under the assumption that 2 µg

from a daily iodine intake of 60 µg are being exhaled.

Effective dose from inhaled 131I did never exceed 100

µSv. Using the same model parameters effective doses

of more than 8 mSv are predicted for out-patient RIT

under worst-case assumptions.



At http://www.uni-

koeln.de/~ainu2/papers/badgas98/index.htm



---------------

It is Steve's friend who has the responsibility for

complying with medical orders.  However, the physics

(if that is the term) for the risks are still the

same.





--- Peter  Fear <FEARP@upstate.edu> wrote:



> John,

> 

> I have a couple of comments -

> 

> Peter Fear

> SUNY Upstate Medical University

> Radiation Safety Office

> 636 UH

> 750 E. Adams St.

> Syracuse, NY 13210

> 

> Phone: (315)464-6510

> FAX:     (315)464-5095

> fearp@upstate.edu

> 

> 

> 

> >>> John Jacobus <crispy_bird@YAHOO.COM> 8/19/2004

> 8:39:34 AM >>>

> .......

> >However, patients do not excrete significant

> amounts

> of iodine.  It is bound to the remanant throid

> tissue;

> proper hand washing and sanitary activities, e.g.,

> using separate eating utensils, precludes the spread

> of contamination.  

> 

> This would probably be true for a 30 mCi dose but a

> pt who is given a much

> higher dose (>100 mCi) will excrete a large amount

> quite quickly. Our major

> therapies go from 200 mCi to <30 mCi in about 2

> days. 

> 

> Secondly, Steve does not give an address and has

> email thru Hotmail. He may

> not be in the US. 

> 

> Pete

> 

> 





=====

+++++++++++++++++++

"Everyone is ignorant, only on different subjects."

Will Rogers



-- John

John Jacobus, MS

Certified Health Physicist

e-mail:  crispy_bird@yahoo.com





		

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