X-ray computed tomography (CT) enables the visualisation and dimensional evaluation of both the internal and external geometry of a workpiece, it is therefore well suited for measuring geometric features that are otherwise inaccessible to tactile and optical instruments. Beam hardening is a wellknown physical process that can degrade the quality of CT images and influence edge detection algorit...

In this paper, we propose an iterative beam hardening correction method that is applicable for the case with multiple materials. By assuming that the materials composing scanned object are known and that they are distinguishable by their linear attenuation coefficients at some given energy, the beam hardening correction problem is converted into a nonlinear system problem, which is then solved ...

In CT, the nonlinear attenuation characteristics of polychromatic X-rays cause beam hardening artifacts in the reconstructed images. Statistical algorithms can effectively correct beam hardening artifacts while providing the benefit of noise reduction. In practice, a big challenge for CT is the difficulty at acquiring accurate energy spectrum information, which hinders the efficiency of beam ha...

Certain regions of the body can be relatively difficult to image optimally by computed tomography (CT). The lower neck falls into this category. A routine transverse image at this level includes the shoulders, which can cause beam hardening [1] . Beam hardening reduces subject contrast and often produces streak artifacts between the shoulders [2, 3]. This image degradation is especially trouble...

When a brass compensator is set in a treatment beam, beam hardening may take place. This variation of the energy spectrum may affect the accuracy of dose calculation by a treatment planning system and the results of dose measurement of brass compensator intensity modulated radiation therapy (IMRT). In addition, when X-rays pass the compensator, scattered photons are generated within the compens...

A 38 year old male patient presented to a radiology center for cone beam computed tomography (CBCT) and the working maxillofacial radiologist spotted a very peculiar finding There was a large piece of metal in the mandible (size 0.5 cm X 0.5 cm). Here in we have provided a commentary on CBCT artifacts seen in this case along with a short explanation on the source of metal. Based on our observat...

High-attenuation object-induced streaking and shadow artifacts in computerized tomography (CT) are somewhat connected to the misfit of the X-ray projection data to the range space of the Radon transform. This misfit is mainly due to the beam hardening factor of the projection data which is unavoidable for polychromatic sources. The major difficulty in dealing with the beam hardening-induced str...

Purpose: This paper proposes a sinogram-consistency learning method to deal with beamhardening related artifacts in polychromatic computerized tomography (CT). The presence of highly attenuating materials in the scan field causes an inconsistent sinogram, that does not match the range space of the Radon transform. When the mismatched data are entered into the range space during CT reconstructio...

Since the introduction of the original singlesection computed tomography (CT) machines, and more recent spiral CT, several different types of CT artefact have been described. Recognized artefacts include motion artefact, metallic streak artefact, beam hardening, partial volume artefact and step artefact. The use of contrast-enhanced spiral CT has created many new artefacts and potential pitfall...

OBJECTIVE To optimize the dose of contrast agent and the level of energy for dual-energy computed tomography (DECT) arthrography of the shoulder joint and to evaluate the benefits of the optimized imaging protocol. MATERIALS AND METHODS Dual-energy scans with monochromatic spectral imaging mode and conventional single energy scans were performed on a shoulder phantom with 10 concentrations fr...