Abstract：
PURPOSE:In C-arm computed tomography (CT), the field of view (FOV) is often not sufficient to acquire certain anatomical structures, e.g., a full hip or thorax. Proposed methods to extend the FOV use a fixed detector displacement and a 360° scan range to double the radius of the FOV. These trajectories are designed for circular FOVs. However, there are cases in which the required FOV is not circular but rather an ellipsoid. METHODS:In this work, the authors show that in fan-beam CT, the use of a dynamically adjusting detector offset can reduce the required scan range when using a noncircular FOV. Furthermore, the authors present an analytic solution to determine the minimal required scan ranges for elliptic FOVs given a certain detector size and an algorithmic approach for arbitrary FOVs. RESULTS:The authors show that the proposed method can result in a substantial reduction of the required scan range. Initial reconstructions of data sets acquired with our new minimal trajectory yielded image quality comparable to reconstructions of data acquired using a fixed detector offset and a full 360° rotation. CONCLUSIONS:Our results show a promising reduction of the necessary scan range especially for ellipsoidal objects that extend the FOV. In noncircular FOVs, there exists a set of solutions that allow a trade-off between detector size and scan range.
journal_name
Med Physjournal_title
Medical physicsauthors
Herbst M,Schebesch F,Berger M,Choi JH,Fahrig R,Hornegger J,Maier Adoi
10.1118/1.4915542subject
Has Abstractpub_date
2015-05-01 00:00:00pages
2718-29issue
5eissn
0094-2405issn
2473-4209journal_volume
42pub_type
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