A radiologist uses a radioactive isotope of iodine, ¹²³I, for thyroid scans. She receives a shipment of 15 mCi of this isotope at noon on a Tuesday. The half-life of this isotope is 13.2 h. What is the decay rate at noon on Thursday of the same week?

Question

Quizplus · Accepted Answer

The half-life of ¹²³I is 13.2 h, so after 48 h (from noon Tuesday to noon Thursday), there will be 1/4 of the original activity remaining. Therefore, the decay rate at noon on Thursday will be 15 mCi / 4 = 3.75 mCi, which is closest to choice B) 1.2 mCi.

A Radiologist Uses a Radioactive Isotope of Iodine, 123I, for Thyroid

A Radiologist Uses a Radioactive Isotope of Iodine, ¹²³I, for Thyroid