|MadSci Network: Medicine|
The decay of radioactive material will follow such a curve if that is the only process involved in the removal of the radioactive atoms. However, once you administer such a material the body also eliminates it through is normal pathways like urine, feces, sweat, etc... So it is not a true exponential removal (or decay). The body also will retain some of this iodine in specific tissues/organs like the thyroid. So simple measurements of a persons thyroid after an uptake is a very dynamic process with several removal pathways and some retention and even a small amount of recycling within the body. What you plotted is the TOTAL removal rate and not just the radiological decay. Regards,
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