A dosimetric intercomparison of megavoltage photon beams in UK radiotherapy centres.

2.50
Hdl Handle:
http://hdl.handle.net/10541/109640
Title:
A dosimetric intercomparison of megavoltage photon beams in UK radiotherapy centres.
Authors:
Thwaites, D I; Williams, J R; Aird, E G; Klevenhagen, S C; Williams, Peter C
Abstract:
A dosimetry intercomparison has been carried out for all 64 radiotherapy centres in the UK. Doses were measured with an ionization chamber in an epoxy resin water-substitute phantom of relatively simple geometry. Reference-point measurements were made for all MV photon beams. For 61 Co-60 beams, a mean ratio of measured-to-stated dose of 1.002 was observed with a standard deviation of 0.014, whilst for 100 MV x-ray beams, the corresponding figures were 1.003 and 0.015. 97% of beams lay within a +/- 3% deviation. One measurement was instrumental in discovering a large discrepancy. Doses were also investigated in two planned three-field distributions at one beam quality in each centre. One of these was in a homogeneous phantom, whilst the second included a lung-equivalent insert. Doses were measured at the central point and at four other points in the high dose volume. In both situations, the mean ratio of measured-to-calculated doses for all points was 1.008, with standard deviations of 0.027 and 0.035 for the uniform and non-uniform phantoms, respectively. Discrepancies over 5% were followed up. The work must be viewed in the context of other international intercomparisons and is an essential part of wider radiotherapy audit processes.
Affiliation:
Department of Medical Physics and Medical Engineering, University of Edinburg, UK.
Citation:
A dosimetric intercomparison of megavoltage photon beams in UK radiotherapy centres. 1992, 37 (2):445-61 Phys Med Biol
Journal:
Physics in Medicine and Biology
Issue Date:
Feb-1992
URI:
http://hdl.handle.net/10541/109640
DOI:
10.1088/0031-9155/37/2/011
PubMed ID:
1553393
Type:
Article
Language:
en
ISSN:
0031-9155
Appears in Collections:
All Christie Publications

Full metadata record

DC FieldValue Language
dc.contributor.authorThwaites, D Ien
dc.contributor.authorWilliams, J Ren
dc.contributor.authorAird, E Gen
dc.contributor.authorKlevenhagen, S Cen
dc.contributor.authorWilliams, Peter Cen
dc.date.accessioned2010-08-16T13:31:13Z-
dc.date.available2010-08-16T13:31:13Z-
dc.date.issued1992-02-
dc.identifier.citationA dosimetric intercomparison of megavoltage photon beams in UK radiotherapy centres. 1992, 37 (2):445-61 Phys Med Biolen
dc.identifier.issn0031-9155-
dc.identifier.pmid1553393-
dc.identifier.doi10.1088/0031-9155/37/2/011-
dc.identifier.urihttp://hdl.handle.net/10541/109640-
dc.description.abstractA dosimetry intercomparison has been carried out for all 64 radiotherapy centres in the UK. Doses were measured with an ionization chamber in an epoxy resin water-substitute phantom of relatively simple geometry. Reference-point measurements were made for all MV photon beams. For 61 Co-60 beams, a mean ratio of measured-to-stated dose of 1.002 was observed with a standard deviation of 0.014, whilst for 100 MV x-ray beams, the corresponding figures were 1.003 and 0.015. 97% of beams lay within a +/- 3% deviation. One measurement was instrumental in discovering a large discrepancy. Doses were also investigated in two planned three-field distributions at one beam quality in each centre. One of these was in a homogeneous phantom, whilst the second included a lung-equivalent insert. Doses were measured at the central point and at four other points in the high dose volume. In both situations, the mean ratio of measured-to-calculated doses for all points was 1.008, with standard deviations of 0.027 and 0.035 for the uniform and non-uniform phantoms, respectively. Discrepancies over 5% were followed up. The work must be viewed in the context of other international intercomparisons and is an essential part of wider radiotherapy audit processes.en
dc.language.isoenen
dc.subject.meshGreat Britain-
dc.subject.meshHumans-
dc.subject.meshModels, Structural-
dc.subject.meshQuality Assurance, Health Care-
dc.subject.meshRadiotherapy Dosage-
dc.subject.meshRadiotherapy, High-Energy-
dc.titleA dosimetric intercomparison of megavoltage photon beams in UK radiotherapy centres.en
dc.typeArticleen
dc.contributor.departmentDepartment of Medical Physics and Medical Engineering, University of Edinburg, UK.en
dc.identifier.journalPhysics in Medicine and Biologyen

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