Radioactivity Basics
Start with the big picture
Radioactive decay can emit alpha or beta particles, gamma rays, or neutrons. Activity describes the rate of decay and is measured in becquerels; absorbed dose is measured in grays, while sieverts account for radiation and tissue weighting. Half-life helps determine how long a radionuclide remains active, influencing imaging timing and exposure. Emissions also differ in penetration: alpha particles travel only a short distance, beta particles penetrate further, and gamma rays can pass deeply through tissue. Positron annihilation produces paired photons used in PET imaging. The topic also introduces radiation detection, shielding, the inverse square law, and the safety principles of time, distance, and shielding. Together, these basics help explain tracer selection and clinical use.
What you'll learn
- Distinguish activity, absorbed dose, and equivalent or effective dose.
- Describe how half-life and decay pathways relate to medical use.
- Compare common emissions by penetration and clinical application.
- Explain basic detection, shielding, and radiation-safety principles.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
