The consequences of fixed-pattern noise and image movement on electronic portal images.

2.50
Hdl Handle:
http://hdl.handle.net/10541/95142
Title:
The consequences of fixed-pattern noise and image movement on electronic portal images.
Authors:
Kirby, Mike C
Abstract:
Fixed-pattern noise in electronic portal images (EPIs) is normally eliminated by dividing raw image data by an open-field calibration image (OFCI). However, for successful elimination, there must be exact registration between the two image sets. Any movement within the imaging system, such as that which occurs with gantry angle, will result in misregistration and a subsequent increase in noise. This paper describes, both qualitatively, by way of example, and quantitatively, by way of variance analysis, the consequences of misregistration and its effects on image quality. Our results show that image quality is found to degrade significantly with change in gantry angle, when a single OFCI is used, with a loss of low-contrast, fine detail. Variance is observed to increase over 2.5-fold. A simple solution of using multiple OFCIs is described, along with a technique for optimizing the number of images required, and the gantry angles at which they are acquired. When five OFCIs are used, the variance changes with gantry angle are limited to less than 20%. These changes are observed in both long and very short exposures (5 MU or 1 s).
Affiliation:
North Western Medical Physics Department, Christie Hospital, Manchester, UK.
Citation:
The consequences of fixed-pattern noise and image movement on electronic portal images. 1996, 41 (11):2345-56 Phys Med Biol
Journal:
Physics in Medicine and Biology
Issue Date:
Nov-1996
URI:
http://hdl.handle.net/10541/95142
DOI:
10.1088/0031-9155/41/11/007
PubMed ID:
8938030
Type:
Article
Language:
en
ISSN:
0031-9155
Appears in Collections:
All Christie Publications

Full metadata record

DC FieldValue Language
dc.contributor.authorKirby, Mike Cen
dc.date.accessioned2010-03-29T11:56:00Z-
dc.date.available2010-03-29T11:56:00Z-
dc.date.issued1996-11-
dc.identifier.citationThe consequences of fixed-pattern noise and image movement on electronic portal images. 1996, 41 (11):2345-56 Phys Med Biolen
dc.identifier.issn0031-9155-
dc.identifier.pmid8938030-
dc.identifier.doi10.1088/0031-9155/41/11/007-
dc.identifier.urihttp://hdl.handle.net/10541/95142-
dc.description.abstractFixed-pattern noise in electronic portal images (EPIs) is normally eliminated by dividing raw image data by an open-field calibration image (OFCI). However, for successful elimination, there must be exact registration between the two image sets. Any movement within the imaging system, such as that which occurs with gantry angle, will result in misregistration and a subsequent increase in noise. This paper describes, both qualitatively, by way of example, and quantitatively, by way of variance analysis, the consequences of misregistration and its effects on image quality. Our results show that image quality is found to degrade significantly with change in gantry angle, when a single OFCI is used, with a loss of low-contrast, fine detail. Variance is observed to increase over 2.5-fold. A simple solution of using multiple OFCIs is described, along with a technique for optimizing the number of images required, and the gantry angles at which they are acquired. When five OFCIs are used, the variance changes with gantry angle are limited to less than 20%. These changes are observed in both long and very short exposures (5 MU or 1 s).en
dc.language.isoenen
dc.subject.meshAnalysis of Variance-
dc.subject.meshEquipment Design-
dc.subject.meshHumans-
dc.subject.meshRadiography-
dc.subject.meshRadiotherapy-
dc.subject.meshReproducibility of Results-
dc.titleThe consequences of fixed-pattern noise and image movement on electronic portal images.en
dc.typeArticleen
dc.contributor.departmentNorth Western Medical Physics Department, Christie Hospital, Manchester, UK.en
dc.identifier.journalPhysics in Medicine and Biologyen

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