Beam hardening is the phenomenon that occurs when an x-ray beam comprised of polychromatic energies passes through an object, resulting in selective attenuation of lower energy photons.

What affects beam hardening?

The beam-hardening effect results from preferential absorption of low-energy photons as a polychromatic x-ray beam passes through an object.

What are the common causes of artifacts in CT?

Physics-based artifacts result from the physical processes involved in the acquisition of CT data. Patient-based artifacts are caused by such factors as patient movement or the presence of metallic materials in or on the patient. Scanner-based artifacts result from imperfections in scanner function.

What causes partial volume effect?

Partial volume effects occur where multiple tissues contribute to a single voxel, resulting in a blurring of intensities at tissue boundaries [3].

What causes streak artifact?

Metal artifact Metal streak artifacts are caused by multiple mechanisms, including beam hardening, scatter, Poisson noise, motion, and edge effects. The Metal Deletion Technique (MDT) is an iterative technique that reduces artifacts due to all of these mechanisms.

What is beam softening?

Abstract. Beam softening is depending on the material atomic number and photon beam energy for photon beam filtration; the filtration quality is essential to producing a clinical beam in external radiotherapy. Beam softening analysis is done using Monte Carlo method.

What causes metal artifact CT?

Metal streak artifacts are caused by multiple mechanisms, including beam hardening, scatter, Poisson noise, motion, and edge effects. The Metal Deletion Technique (MDT) is an iterative technique that reduces artifacts due to all of these mechanisms. In some cases, the improved image quality can change the diagnosis.

What is cone beam effect?

Cone beam effect artifacts are seen in multidetector row CT (cone beam CT) acquisitions 1. Modern CT scanners use more detector arrays to increase the number of sections acquired per rotation. This causes the x-ray beams to become cone-shaped as opposed to fan-shaped 2.

What is cone beam artifact?

What is meant by partial volume artifact?

Partial volume artifact occurs when tissues of widely different absorption are encompassed on the same CT voxel producing a beam attenuation proportional to the average value of these tissues.

What is the definition of beam hardening?

Beam hardening is the phenomenon occurring when an x-ray beam comprised of polychromatic energies passes through an object, resulting in selective attenuation of lower energy photons.

What is beam hardening?

Beam hardening is the phenomenon that occurs when an x-ray beam comprised of polychromatic energies passes through an object, resulting in selective attenuation of lower energy photons.

What is beam hardening in CT?

Beam Hardening. The most commonly encountered artifact in CT scanning is beam hardening, which causes the edges of an object to appear brighter than the center, even if the material is the same throughout (Fig. 5a).