Chapter 21, Problem 21.78QP

Interpretation Introduction

Interpretation: Iodine- $123$ $\left(t_{1/2}=13.3\text{h}\right)$ is given to have replaced iodine- $131$ $\left(t_{1/2}=8.1\text{h}\right)$ for the diagnosis of thyroid conditions. The time in which the activity of the ${}^{123}\text{I}$ drops to $5\%$ of its initial value is to be calculated.

Concept introduction: Isotopes are the species of same element which differ only by the number of neutrons or by mass number.

The iodine has many isotopes; some of them are Iodine- $123$, iodine- $131$, iodine- $129$ and iodine- $124$.

The isotope iodine- $131$ is radioactive in nature and it is used in nuclear medicine imagining and also used for diagnosis of thyroid conditions.

To determine: The time in which the activity of the ${}^{123}\text{I}$ drops to $5\%$ of its initial value.