Geometric Misalignment Calibration and Detector Lag Effect Artifact Correction in a Cone-Beam Flat Panel micro-CT System for Small Animal Imaging
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
The cone-beam flat panel micro-CT is a high definition imaging system. It acquires projections of an object or animal to reconstruct a 3D image of its internal structure. The device is basically composed by a radiation tube and a detector panel, which are fixed to a gantry that rotates all around the test subject. The micro-CT system is affected by several imperfections and problems, that might lead to serious artifacts that deteriorate the quality of the reconstructed image. In particular, two issues have been discussed in the present work: the source-panel geometric misalignment and the detector lag effect. The first problem concerns the consequences of systems where the different elements are not perfectly aligned to each other. The second issue regards the residual signal, left in the detector's sensor after a projection acquisition, which affects the following frames with ghost images. Both these arguments have been investigated to describe their characteristics and behaviour in a typical acquisition protocol. Then two correction methods have been presented and tested on a real micro-CT device to verify their effectiveness in the artifacts compensation. In the end, a comparison between images before and after the corrections is provided and future prospects are discussed.
Place, publisher, year, edition, pages
2015. , 118 p.
medical, engineering, imaging, CT, microCT, animal, calibration, misalignment, geometric, detector, lag effect, artifact, correction, cone-beam, flat panel
IdentifiersURN: urn:nbn:se:kth:diva-179873OAI: oai:DiVA.org:kth-179873DiVA: diva2:890787
Subject / course
Master of Science - Medical Engineering
Colarieti-Tosti, Massimiliano, Associate Professor
Nilsson, Mats, PhD