skip to main content

Title: Novel ultrahigh resolution data acquisition and image reconstruction for multi-detector row CT

We present and evaluate a special ultrahigh resolution mode providing considerably enhanced spatial resolution both in the scan plane and in the z-axis direction for a routine medical multi-detector row computed tomography (CT) system. Data acquisition is performed by using a flying focal spot both in the scan plane and in the z-axis direction in combination with tantalum grids that are inserted in front of the multi-row detector to reduce the aperture of the detector elements both in-plane and in the z-axis direction. The dose utilization of the system for standard applications is not affected, since the grids are moved into place only when needed and are removed for standard scanning. By means of this technique, image slices with a nominal section width of 0.4 mm (measured full width at half maximum=0.45 mm) can be reconstructed in spiral mode on a CT system with a detector configuration of 32x0.6 mm. The measured 2% value of the in-plane modulation transfer function (MTF) is 20.4 lp/cm, the measured 2% value of the longitudinal (z axis) MTF is 21.5 lp/cm. In a resolution phantom with metal line pair test patterns, spatial resolution of 20 lp/cm can be demonstrated both in the scan planemore » and along the z axis. This corresponds to an object size of 0.25 mm that can be resolved. The new mode is intended for ultrahigh resolution bone imaging, in particular for wrists, joints, and inner ear studies, where a higher level of image noise due to the reduced aperture is an acceptable trade-off for the clinical benefit brought about by the improved spatial resolution.« less
Authors:
; ; ; ; ;  [1] ;  [2] ;  [3]
  1. Siemens Medical Solutions, Computed Tomography CTE PA Siemensstr. 1, 91301 Forchheim (Germany) and Department of Diagnostic Radiology, Eberhard-Karls-Universitaet Tuebingen (Germany)
  2. (Germany)
  3. (United States)
Publication Date:
OSTI Identifier:
20951302
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 34; Journal Issue: 5; Other Information: DOI: 10.1118/1.2722872; (c) 2007 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; AUDITORY ORGANS; COMPUTERIZED TOMOGRAPHY; DATA ACQUISITION; IMAGE PROCESSING; IMAGES; PHANTOMS; RADIATION DOSES; SKELETON; SPATIAL RESOLUTION; TANTALUM; TRANSFER FUNCTIONS