Verification of dynamic multileaf collimation using an electronic portal imaging device.

2.50
Hdl Handle:
http://hdl.handle.net/10541/86512
Title:
Verification of dynamic multileaf collimation using an electronic portal imaging device.
Authors:
James, H V; Atherton, S; Budgell, Geoff J; Kirby, Mike C; Williams, Peter C
Abstract:
High standards of treatment verification are necessary where complex new delivery techniques, such as intensity modulated radiation therapy using dynamic multileaf collimation, are being developed. This paper describes the use of a fluoroscopic electronic portal imaging device (EPID) to provide real-time qualitative verification of leaf position during delivery of a dynamic MLC prescription in addition to off-line quantitative verification. A custom-built circuit triggers the EPID to capture a series of snap-shot images at equally spaced dose points during a dynamic MLC prescription. Real-time verification is achieved by overlaying a template of expected leaf positions onto the images as they are acquired. Quantitative off-line verification is achieved using a maximum gradient edge detection algorithm to measure individual leaf positions for comparison with required leaf positions. Investigations have been undertaken to optimize image acquisition and assess the edge detection algorithm for variations in machine dose rate, leaf velocity and beam attenuation. On-line verification enables the operator to monitor the progress of a dynamic delivery and has been used for independent confirmation of accurate dynamic delivery during intensity modulated treatments. Off-line verification allows measurement of leaf position with a precision of 1 mm although image acquisition times must be less than or equal to 140 ms to ensure coincidence of the maximum gradient in the image with the 50% dose level.
Affiliation:
North Western Medical Physics, Christie Hospital, Manchester, UK. hayley.james@ipsh-tr.anglox.nhs.uk
Citation:
Verification of dynamic multileaf collimation using an electronic portal imaging device. 2000, 45 (2):495-509 Phys Med Biol
Journal:
Physics in Medicine and Biology
Issue Date:
Feb-2000
URI:
http://hdl.handle.net/10541/86512
DOI:
10.1088/0031-9155/45/2/316
PubMed ID:
10701517
Type:
Article
Language:
en
ISSN:
0031-9155
Appears in Collections:
All Christie Publications

Full metadata record

DC FieldValue Language
dc.contributor.authorJames, H Ven
dc.contributor.authorAtherton, Sen
dc.contributor.authorBudgell, Geoff Jen
dc.contributor.authorKirby, Mike Cen
dc.contributor.authorWilliams, Peter Cen
dc.date.accessioned2009-11-19T16:51:55Z-
dc.date.available2009-11-19T16:51:55Z-
dc.date.issued2000-02-
dc.identifier.citationVerification of dynamic multileaf collimation using an electronic portal imaging device. 2000, 45 (2):495-509 Phys Med Biolen
dc.identifier.issn0031-9155-
dc.identifier.pmid10701517-
dc.identifier.doi10.1088/0031-9155/45/2/316-
dc.identifier.urihttp://hdl.handle.net/10541/86512-
dc.description.abstractHigh standards of treatment verification are necessary where complex new delivery techniques, such as intensity modulated radiation therapy using dynamic multileaf collimation, are being developed. This paper describes the use of a fluoroscopic electronic portal imaging device (EPID) to provide real-time qualitative verification of leaf position during delivery of a dynamic MLC prescription in addition to off-line quantitative verification. A custom-built circuit triggers the EPID to capture a series of snap-shot images at equally spaced dose points during a dynamic MLC prescription. Real-time verification is achieved by overlaying a template of expected leaf positions onto the images as they are acquired. Quantitative off-line verification is achieved using a maximum gradient edge detection algorithm to measure individual leaf positions for comparison with required leaf positions. Investigations have been undertaken to optimize image acquisition and assess the edge detection algorithm for variations in machine dose rate, leaf velocity and beam attenuation. On-line verification enables the operator to monitor the progress of a dynamic delivery and has been used for independent confirmation of accurate dynamic delivery during intensity modulated treatments. Off-line verification allows measurement of leaf position with a precision of 1 mm although image acquisition times must be less than or equal to 140 ms to ensure coincidence of the maximum gradient in the image with the 50% dose level.en
dc.language.isoenen
dc.subject.meshAlgorithms-
dc.subject.meshHumans-
dc.subject.meshImage Processing, Computer-Assisted-
dc.subject.meshParticle Accelerators-
dc.subject.meshPhantoms, Imaging-
dc.subject.meshRadiotherapy Dosage-
dc.subject.meshRadiotherapy Planning, Computer-Assisted-
dc.subject.meshRadiotherapy, Computer-Assisted-
dc.titleVerification of dynamic multileaf collimation using an electronic portal imaging device.en
dc.typeArticleen
dc.contributor.departmentNorth Western Medical Physics, Christie Hospital, Manchester, UK. hayley.james@ipsh-tr.anglox.nhs.uken
dc.identifier.journalPhysics in Medicine and Biologyen

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