Final answer:
The student's question relates to applying principles of radiation and half-life to calculate thyroid uptake and to find and compare masses of different iodine isotopes used in medical scans.
Step-by-step explanation:
The question asks to calculate the thyroid uptake and subsequently find and compare the masses of isotopes I-131 and I-123 used in thyroid scans, given their respective half-lives. We would use the counts given (standard, background, thyroid, thigh) to calculate uptake and the known activities of the isotopes alongside their half-lives to find their masses. Additionally, the principles of radioactive decay and its medical application are discussed as well.