Question

Which of the following is a possible manifestation of beam hardening?

1) CT number inaccuracies
2) steaks in the image
3) cupping artifacts

Answer 1

Beam hardening in CT imaging can lead to several artifacts including CT number inaccuracies, streaks in the image, and cupping artifacts. These phenomena occur as a result of the higher energy photon's lower absorption rates which cause misrepresentation of actual densities in the scanned tissue.

Step-by-step explanation:

The phenomenon of beam hardening is a type of artifact that can affect the quality of computed tomography (CT) images. This occurs when lower energy photons are absorbed more than higher energy photons as an x-ray beam passes through an object, causing the remaining beam to have a higher average energy, or to be 'hardened'.

This can indeed result in various artifacts in the CT image. The potential manifestations listed can all be attributed to beam hardening:

1. CT number inaccuracies - The altered energy spectrum of the X-rays can cause incorrect calculations of the CT numbers, which represent the radiodensity of tissues.
2. Streaks in the image - Due to uneven absorption in different parts of the image, some areas may be misrepresented as having different densities, resulting in streaking.
3. Cupping artifacts - This happens when the center of a homogeneous material appears less dense than its edges on a CT scan, which can be misinterpreted as an actual characteristic of the material, rather than an artifact.

Preventing and correcting these artifacts is important for accurate diagnosis and treatment planning.