Post a New Question

calculus -- PLEASE HELP!

posted by .

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?

I got this:

D = int dt Io e^-.0866 t from t=0 to t = 8
but what do I do after that to get B and C?

  • calculus -- PLEASE HELP! -

    Now I did this yesterday :)
    However I did it in days and for part 2 you need it in hours.

    To do it in hours, get 8 days in hours
    8*24 = 192 hours half life
    so
    I = Io e^-kt now t in hours
    .5 = e^-192 t
    ln .5 = -.693 = -192 k
    k = .00361
    so
    I = Io e^-.00361 t
    Now do your integral from t = 0 to t = 8 days
    D = int I dt = int Io e^-.00361 t from t = 0 to t = 192
    or
    D = (Io/.00361)(1/2)= 138 Io
    so
    10^7 millirem = 10^4 rem = 138 Io
    so
    Io = 10,000/138 = 72.5 rem/hr = 72.5*10^3 millirem/hr

    now in 6 weeks
    6 weeks = 7*24*6 = 1008 hr
    D = (Io /.00361)(1-e^-(.00631*1008))
    D = (72.5*10^3/.00361)(1 essentially)
    D = 20083*10^3 millirems = 20*10^6 millirems essentially or about twice the total dose we got in one half life logically enough

  • calculus -- PLEASE HELP! -

    A patient is given a 5 mCi dose of 131I. Estimate the activity of her thyroid after 4 days. (Assume that all remaining 131I has been absorbed by her thyroid. Radioactive half-life of 131I is 8 days and it has a biological half-life of 138 days

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. CALC -- integrals!

    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 …
  2. chem

    Iodine-131 is often used in nuclear medicine to obtain images of the thyroid. If you start with 3.6 109 I-131 atoms, how many are left after approximately 1 month?
  3. chemistry

    Iodine-131 is used to destroy thyroid tissue in the treatment of an overactive thyroid. the half-life of iodine-131 is 8.02 days. if a hospital receives a shipment of 200.0g of iodine-131, how much iodine-131 would remain after 32 …
  4. Math please help!

    Nuclear medicine technologists use the Iodine isotope I-131, with a half-life of 8 days,to check thyroid function of patients. After ingesting a tablet containing the iodine, the isotopes collect in a patient's thyroid, and a special …
  5. Math

    Please show me how to solve: Doctors can use radioactive iodine to treat some forms of cancer. The half-life of iodine - 131 is 8 days. A patient receives a treatment of 12 millicuries of iodine - 131. (A mullicurie is a unit of radioactivity.) …
  6. Exponential Growth and Decay

    Doctors use iodine-131 to treat some forms of cancer. The half-life of iodine-131 is 8 days. A patient receives a treatment of 12 millicuries. A millicurie is a unit of radioactivity. How much iodine-131 remains in the patient 16 days …
  7. Chemistry

    2. The half-life of a radioactive element is important when considering its application in medicine. For example, iodine-131 is often used in the imaging of the thyroid. The reason is that iodine is readily absorbed by the thyroid …
  8. Chemistry

    How long will it take for a 18.0-g sample of iodine-131 to decay to leave a total of 2.25 g of the isotope?
  9. science

    A Geiger counter is used to measure the activity of a sample of iodine-131. Based on the data, what is the half-life of iodine-131?
  10. Pre calc 12 urgent help pls!

    Radioisotopes are used to diagnoa various illnesses. Iodine-131 is adminsitred to diagnoaw thyriod gland activity. Original dosage contains 280 MBq of Iodine-131. If. One is lost from body then after 6h, there r 274 MBq. What is half …

More Similar Questions

Post a New Question