Helical cone beam CT with an asymmetrical detector

Journal Article · Sat Oct 15 04:00:00 EDT 2005 · Medical Physics

DOI:https://doi.org/10.1118/1.2047784· OSTI ID:20726382

Zamyatin, Alexander A; Taguchi, Katsuyuki; Silver, Michael D ^[1]

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1. Bio-Imaging Research, Inc., 425 Barclay Blvd., Lincolnshire, Illinois 60069 (United States)

If a multislice or other area detector is shifted to one side to cover a larger field of view, then the data are truncated on one side. We propose a method to restore the missing data in helical cone-beam acquisitions that uses measured data on the longer side of the asymmetric detector array. The method is based on the idea of complementary rays, which is well known in fan beam geometry; in this paper we extend this concept to the cone-beam case. Different cases of complementary data coverage and dependence on the helical pitch are considered. The proposed method is used in our prototype 16-row CT scanner with an asymmetric detector and a 700 mm field of view. For evaluation we used scanned body phantom data and computer-simulated data. To simulate asymmetric truncation, the full, symmetric datasets were truncated by dropping either 22.5% or 45% from one side of the detector. Reconstructed images from the prototype scanner with the asymmetrical detector show excellent image quality in the extended field of view. The proposed method allows flexible helical pitch selection and can be used with overscan, short-scan, and super-short-scan reconstructions.

• OSTI ID: 20726382
• Journal Information: Medical Physics, Journal Name: Medical Physics Journal Issue: 10 Vol. 32; ISSN 0094-2405; ISSN MPHYA6
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
ASYMMETRY
BEAMS
COMPUTERIZED SIMULATION
COMPUTERIZED TOMOGRAPHY
IMAGE PROCESSING
IMAGES
PHANTOMS
PITCHES