Transmission & Attenuation

How Excitation and Ionization Shape Radiation Interactions

When radiation passes through matter, three things can happen:

1. Transmission: The radiation passes straight through without interacting.

2. Scattering: The radiation interacts with atoms and changes direction, losing some energy in the process.

3. Absorption: The radiation is completely absorbed by the material.

The second and third processes together are called attenuation. Attenuation describes the overall reduction in the intensity of the radiation beam as it passes through matter, whether that’s due to scattering or absorption.

Understanding attenuation is crucial because it explains why radiation intensity decreases with depth in tissue, which directly affects how we plan and deliver treatments in radiation therapy.

In the next lesson, we’ll look more closely at how these interactions happen, starting with the photoelectric effect.

Keep the photons flowing,

Sara