Exact and approximate algorithms for helical cone-beam CT.
نویسندگان
چکیده
This paper concerns image reconstruction for helical x-ray transmission tomography (CT) with multi-row detectors. We introduce two approximate cone-beam (CB) filtered-backprojection (FBP) algorithms of the Feldkamp type, obtained by extending to three dimensions (3D) two recently proposed exact FBP algorithms for 2D fan-beam reconstruction. The new algorithms are similar to the standard Feldkamp-type FBP for helical CT. In particular, they can reconstruct each transaxial slice from data acquired along an arbitrary segment of helix, thereby efficiently exploiting the available data. In contrast to the standard Feldkamp-type algorithm, however, the redundancy weight is applied after filtering, allowing a more efficient numerical implementation. To partially alleviate the CB artefacts, which increase with increasing values of the helical pitch, a frequency-mixing method is proposed. This method reconstructs the high frequency components of the image using the longest possible segment of helix, whereas the low frequencies are reconstructed using a minimal, short-scan, segment of helix to minimize CB artefacts. The performance of the algorithms is illustrated using simulated data.
منابع مشابه
Simple Quasi-Exact Filtered Backprojection Algorithms for Long-Object Problem in Helical Cone-Beam Tomography
Since the development of multi-slice helical CT, cone-beam reconstruction with a helical vertex path is receiving increasing attention. The current multi-slice CT scanners are adopting a class of approximate reconstruction algorithms which can be viewed an extension of the 2-D FBP algorithm. However, these approximate algorithms break down as the pitch of helix becomes large. In fact, major com...
متن کاملReview of Recent Developments in Cone-beam Ct Reconstruction Algorithms for Long-object Problem
Long-object problem and short-object problem both deal with reconstruction problems with truncated conebeam CT projections acquired with a helical path. They have significantly less practical limitations than original exact cone-beam CT reconstruction algorithms which the cone-beam must cover the whole object. The short-object problem can be defined as reconstruction of the whole object having ...
متن کاملPI-line-based image reconstruction in helical cone-beam computed tomography with a variable pitch.
Current applications of helical cone-beam computed tomography (CT) involve primarily a constant pitch where the translating speed of the table and the rotation speed of the source-detector remain constant. However, situations do exist where it may be more desirable to use a helical scan with a variable translating speed of the table, leading a variable pitch. One of such applications could aris...
متن کاملExact Reconstruction From Uniformly Attenuated Helical Cone-Beam Projections in SPECT
In recent years the development of cone-beam reconstruction algorithms has been an active research area in x-ray computed tomography (CT), and significant progress has been made in the advancement of algorithms. Theoretically exact and computationally efficient analytical algorithms can be found in the literature. However, in single photon emission computed tomography (SPECT), published cone-be...
متن کاملGuest Editorial - Multirow Detector and Cone-Beam Spiral/Helical CT
S PIRAL/HELICAL multirow detector computed tomog-raphy (MDCT), also referred to as multislice spiral CT (MSCT), has attracted a major interest since its recent introduction [18], [33]. Compared with single-row-detector systems, MDCT scanners allow faster data collection and thinner slices that support more demanding clinical applications and present new research opportunities. This special issu...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Physics in medicine and biology
دوره 49 13 شماره
صفحات -
تاریخ انتشار 2004