A novel metal artifact reducing method for cone-beam CT based on three approximately orthogonal projections

Abstract

Metal artifacts remain a challenge for computed tomography (CT) reconstruction, especially for medical CT, in which the radiation dose for patients is strictly limited. This study presents a novel method of reducing the metal artifacts for cone-beam CT by renovating the metal areas in the 2D cone-beam projection. We first calculate the 3D coordinates of all the metallic implants, which will then be projected into the projection images in each angle as the metal seed points (MSPs), increasing the precision of the segmentation of the metal areas. Different from the existing methods of calculating the metal positions with two projection images, we proposed a new method to calculate the 3D coordinates of all the metallic implants using three different projection images that are nearly orthogonal. One is the parallel-beam projection image along the Z-axial direction (i.e. along the rotation axis) calculated by the projection synthesizing method, while the other two are the cone-beam projections at two different views chosen from the scanned data. The three nearly orthogonal views will greatly help to accurately locate the metallic implants when there is more than one implant in the object. Then the MSPs can be located in each projection by geometry calculations. The region growing segmentation method and the bilinear interpolation method are used to modify the projection areas of the metallic implants. Experimental studies demonstrate that this method is accurate in locating MSPs and efficient in reducing metal artifacts.

Fast Metabolic Response to Drug Intervention Through Analysis on a Miniaturized, Highly Integrated Molecular Imaging System

“…The beta particle imaging camera has been reported(3). For this work, the camera was miniaturized to be portable and simple to operate.…”

Emerging clinical applications of computed tomography

“…However, in the last decade, the high stability of the modern CT scanners have fostered application of CT thermometry. Its feasibility has been assessed during different types of hyperthermal procedures in ex vivo models, on phantoms, and in a preliminary study involving an in vivo pig model 60–62. Although CT-based thermometry is in its infancy, recent improvement in the performance of CT scanners and the increasing interest in monitoring of temperature during thermal procedures are helping to increase the number of studies focusing on this technique.…”

Deblurring Computed Tomography Medical Images Using a Novel Amended Landweber Algorithm

“…However, it is known that every captured image is a degraded version of the original due to the frequent and inevitable errors generated during the imaging process [4]. Therefore, different types of degradation are observed on CT medical images, such as noise [5], low-contrast artifact [6], blur [7], streak artifact [8], metal artifact [9], ring artifact [10], out-of-field artifact [11] and limited-angle artifact [12].…”