In: Physics
Radioactive iodine is given to patients to reduce thyroid growth or activity. The iodine I53131, has a half-life of 8.04 days. Why would the radiation in the human body decrease at a faster rate than at the calculated rate?
This question can be treated theoretically. The effective half-life of radioactive material in human body is
I131 is a radioactive substance with half-life 8.04 days, that undergoes beta decay, the Human body has a thyroid gland that needs iodine to produce thyroid. The thyroid gland cannot differentiate between stable and radioactive Iodine.
The effective half-life in the body is the time required for the amount of a radioactive element deposited in a living organism. That comes from the combined action of physical decay and biologic disappearance. The body absorbs I131, it retains the material. So, patients treated for carcinoma thyroid, because of surgical removal of thyroid tissues, elimination of I-131 radioactivity clears at a faster rate.
With a large sample test and calculation, it is found that the effective half-life of I131 is 5.5 days in a human body, slightly varies with age.