Document Detail

Principles of CT: radiation dose and image quality.
MedLine Citation:
PMID:  18006597     Owner:  NLM     Status:  MEDLINE    
This article discusses CT radiation dose, the measurement of CT dose, and CT image quality. The most commonly used dose descriptor is CT dose index, which represents the dose to a location (e.g., depth) in a scanned volume from a complete series of slices. A weighted average of the CT dose index measured at the center and periphery of dose phantoms provides a convenient single-number estimate of patient dose for a procedure, and this value (or a related indicator that includes the scanned length) is often displayed on the operator's console. CT image quality, as in most imaging, is described in terms of contrast, spatial resolution, image noise, and artifacts. A strength of CT is its ability to visualize structures of low contrast in a subject, a task that is limited primarily by noise and is therefore closely associated with radiation dose: The higher the dose contributing to the image, the less apparent is image noise and the easier it is to perceive low-contrast structures. Spatial resolution is ultimately limited by sampling, but both image noise and resolution are strongly affected by the reconstruction filter. As a result, diagnostically acceptable image quality at acceptable doses of radiation requires appropriately designed clinical protocols, including appropriate kilovolt peaks, amperages, slice thicknesses, and reconstruction filters.
Lee W Goldman
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Publication Detail:
Type:  Journal Article; Review     Date:  2007-11-15
Journal Detail:
Title:  Journal of nuclear medicine technology     Volume:  35     ISSN:  0091-4916     ISO Abbreviation:  J Nucl Med Technol     Publication Date:  2007 Dec 
Date Detail:
Created Date:  2007-12-06     Completed Date:  2008-02-27     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0430303     Medline TA:  J Nucl Med Technol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  213-25; quiz 226-8     Citation Subset:  IM    
Department of Radiation Therapy and Medical Physics, Hartford Hospital, 80 Seymour Street, Hartford, CT 06102, USA.
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MeSH Terms
Clinical Protocols
Phantoms, Imaging
Radiation Dosage*
Radiotherapy Planning, Computer-Assisted
Sensitivity and Specificity
Tomography, X-Ray Computed / instrumentation,  methods*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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