Question

Name two isotopes that have been used as tracers.

Short answer

Technetium-99m and Carbon-14 are commonly used isotope tracers.

Step-by-step solution

Understand Isotopes

Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons. As a result, they have different mass numbers but similar chemical properties.

Know Common Tracer Uses

Isotopes are often used as tracers in various fields such as medicine, archaeology, and environmental studies. They are selected based on their stability and half-life.

Identify Medical Isotope Tracer

One commonly used isotope tracer in medicine is Technetium-99m ( ^99mTc"). This isotope is used in medical imaging due to its ideal half-life and radiation emission properties.

Identify Archaeological Isotope Tracer

Carbon-14 ( ^14C") is frequently used as a tracer in archaeology to date organic materials. Its radioactive decay allows scientists to estimate the age of ancient biological artifacts.

Key concepts

Technetium-99m

Technetium-99m, abbreviated as \( ^{99m}\text{Tc} \), is a widely used radioactive isotope in the field of nuclear medicine. Its primary use is in diagnostic imaging procedures, which help visualize and assess different organs and tissues within the body. This makes it incredibly valuable for detecting abnormalities and conditions such as cancer, heart disease, and bone disorders.
One of the key reasons for its popularity is its ideal physical properties for medical imaging:

• It emits gamma rays, which can be captured to create highly detailed images via a gamma camera.
• It has a half-life of approximately six hours, which is perfect for medical procedures because it provides enough time to conduct scans but minimizes radiation exposure to patients.

The harmless decay properties and effective visualization capabilities make Technetium-99m a cornerstone tool in modern medical diagnostics.

Carbon-14

Carbon-14, denoted as \( ^{14}\text{C} \), is a radioactive isotope of carbon that plays a crucial role in the field of archaeology. It is predominantly used in the radiocarbon dating technique, which helps determine the age of ancient organic materials. This process is essential for understanding historical timelines and the development of human activities over millennia.
In the environment, Carbon-14 is continuously created in the atmosphere by cosmic rays. Living organisms absorb Carbon-14 and stable carbon isotopes (such as Carbon-12) in different ratios. When an organism dies, it stops absorbing carbon, and the Carbon-14 present begins to decay at a known rate. By measuring the remaining \(^{14}\text{C} \) content in an archaeological specimen:

• Scientists can estimate the time since the organism died.
• It allows researchers to construct more accurate historical timelines.

Carbon-14's stable decay over thousands of years makes it an invaluable tool for dating past events and understanding historical contexts.

Radioactive Decay

Radioactive decay is a fundamental process in which an unstable atomic nucleus loses energy by emitting radiation. This process results in the formation of a more stable nucleus. There are several types of radioactive decay, but the most common involve alpha, beta, and gamma emissions.
Radioactive isotopes, such as Technetium-99m and Carbon-14, undergo regular decay, which is predictable and measurable over time. A crucial concept associated with this is the half-life, which is the time required for half of the starting amount of a radioactive isotope to decay:

• For Technetium-99m, the half-life is about six hours, making it ideal for medical scans.
• In the case of Carbon-14, the half-life is approximately 5,730 years, suitable for dating ancient artifacts.

Understanding radioactive decay is essential for effectively using isotopes as tracers because it informs us of how long an isotope will remain active and useful for practical applications.