Image degradation and stroboscopic images caused by rotary motion of the object in X-ray computed tomography

✍ Scribed by Takashi Sakamoto; Shunsuke Sato

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 635 KB
• Volume: 24
• Category: Article
• ISSN: 0882-1666
• DOI: 10.1002/scj.4690240908

✦ Synopsis

Abstract

In an X‐ray computed tomography (CT), time to scan an object must be allowed to obtain its projection data. If the object is not steady during the scanning, its reconstructed image would contain errors called “motion artifacts.” Recently, two kinds of motion artifact, “blurred image” and “stroboscopic image,” have been found in clinical experience, and their theoretical analyses have been demanded. Assuming that an object is a rigid body, its motion can be divided into rotary and parallel motions.

This paper analyzes the degradation of reconstructed images and artifacts due to the rotary motion of a rigid object. The degradation of a CT image caused by rotation of an arbitrarily shaped rigid object is formulated by using a point‐spread function. The characteristics of blurred images of a rigid object due to its rotation in a CT and the shape of blurred images also are analyzed. The cause of stroboscopic images is explained by using line sources. The theories have been confirmed by computer simulation.