Posted by **anonymous** on Monday, February 4, 2008 at 2:47pm.

Iodine-131 is used to treat hypo-thyroidism since it is preferentially absorbed by the thyroid and typically involves a total radiation dosage of 10,000,000 millirem. Iodine-131 has a half-life of eight days.

1. Set up the appropriate integral to represent the radiation dosage delivered by the absorbed iodine in eight days.

2. Use the fact that eight days is the half-life of the isotope to find the initial radiation intensity in millrems/hour.

3. To the nearest 10 millirems, how much of the total radiation is delivered in six weeks?

- CALC -- integrals! -
**Damon**, Monday, February 4, 2008 at 5:02pm
well, we know the intensity is exponential in time.

I = Io e^-kt

the half life is 8 days

I/Io = .5 = e^-8k

ln .5 = -8k

-.693147=-8k

k = .0866

so

I = Io e^-.0866 t

now total over 8 days, call it D for dose

D = int I dt

D = int dt Io e^-.0866 t from t=0 to t = 8

D = (Io/-.0866) [ e^-.0866(8)-e^0]

e^0 = 1 of course

e^-.6931 = .5 of course

so

D = .5 Io/.0866

or

Io = 5.77 D

D is given of course so you are there in millirems /24 hours

I will leave the doing it in hours and the six weeks thing for you

## Answer This Question

## Related Questions

- calculus -- PLEASE HELP! - Iodine-131 is used to treat hypo-thyroidism since it ...
- chemistry - Iodine-131 is used to destroy thyroid tissue in the treatment of an ...
- Chemistry - 2. The half-life of a radioactive element is important when ...
- Math - Please show me how to solve: Doctors can use radioactive iodine to treat ...
- Exponential Growth and Decay - Doctors use iodine-131 to treat some forms of ...
- chem - Iodine-131 is often used in nuclear medicine to obtain images of the ...
- Math please help! - Nuclear medicine technologists use the Iodine isotope I-131...
- science - A Geiger counter is used to measure the activity of a sample of ...
- Chemistry - How long will it take for a 18.0-g sample of iodine-131 to decay to ...
- math-natural log - Nuclear medicine technologists use the Iodine isotope I-131, ...

More Related Questions