Output correction factors for small static fields in megavoltage photon beams for seven ionization chambers in two orientations — perpendicular and parallel
Purpose The goal of the present work was to provide a large set of detector‐specific output correction factors for seven small volume ionization chambers on two linear accelerators in four megavoltage photon beams utilizing perpendicular and parallel orientation of ionization chambers in the beam fo...
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| Veröffentlicht in: | Medical physics (Lancaster) 2020-01, Vol.47 (1), p.242-259 |
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| creator | Casar, Božidar Gershkevitsh, Eduard Mendez, Ignasi Jurković, Slaven Saiful Huq, M. |
| description | Purpose
The goal of the present work was to provide a large set of detector‐specific output correction factors for seven small volume ionization chambers on two linear accelerators in four megavoltage photon beams utilizing perpendicular and parallel orientation of ionization chambers in the beam for nominal field sizes ranging from 0.5 cm2 × 0.5 cm2 to 10 cm2 × 10 cm2. The present study is the second part of an extensive research conducted by our group.
Methods
Output correction factors kQclin,Qreffclin,fref were experimentally determined on two linacs, Elekta Versa HD and Varian TrueBeam for 6 and 10 MV beams with and without flattening filter for nine square fields ranging from 0.5 cm2 × 0.5 cm2 to 10 cm2 × 10 cm2, for seven mini and micro ionization chambers, IBA CC04, IBA Razor, PTW 31016 3D PinPoint, PTW 31021 3D Semiflex, PTW 31022 3D PinPoint, PTW 31023 PinPoint, and SI Exradin A16. An Exradin W1 plastic scintillator and EBT3 radiochromic films were used as the reference detectors.
Results
For all ionization chambers, values of output correction factors kQclin,Qreffclin,fref were lower for parallel orientation compared to those obtained in the perpendicular orientation. Five ionization chambers from our study set, IBA Razor, PTW 31016 3D PinPoint, PTW 31022 3D PinPoint, PTW 31023 PinPoint, and SI Exradin A16, fulfill the requirement recommended in the TRS‐483 Code of Practice, that is, 0.95 |
| doi_str_mv | 10.1002/mp.13894 |
| format | Article |
| fullrecord | <record><control><sourceid>proquest_pubme</sourceid><recordid>TN_cdi_pubmedcentral_primary_oai_pubmedcentral_nih_gov_7003763</recordid><sourceformat>XML</sourceformat><sourcesystem>PC</sourcesystem><sourcerecordid>2311659511</sourcerecordid><originalsourceid>FETCH-LOGICAL-c4764-92e3911507fd389ebd4ff768f57edadcd7ca8beb7050f3cfaf6b08719e27a13d3</originalsourceid><addsrcrecordid>eNp1kcFu1DAQhi0EoktB4gmQj1xS7DiJkwsSqmhBKiqHcrYm9njXyImD7WxVTn2Innk4noSwuxQ49DSH-f9vfs1PyEvOTjhj5ZthOuGi7apHZFVWUhRVybrHZMVYVxVlxeoj8iylr4yxRtTsKTkSvJGylO2K_Lic8zRnqkOMqLMLI7Wgc4iJ2hBpGsB7mjJkp6l16E2ibqQDrmEbfIY10mkT8uLqEYaDB7c40oXkvsMOqDcw9Bh3znwdaIgOx7zbJfrz9o5OGCccjdOzh0hhNHSCuBxG_5w8seATvjjMY_Ll7P3V6Yfi4vL84-m7i0JXsqmKrkTRcV4zac3yB-xNZa1sWltLNGC0kRraHnvJamaFtmCbnrWSd1hK4MKIY_J2z53mfkCjl3xLADVFN0C8UQGc-n8zuo1ah62SjAnZiAXw-gCI4duMKavBJY3ew4hhTqoUnDd1V3P-V6pjSCmivT_Dmfpdpxomtatzkb76N9a98E9_i6DYC66dx5sHQerT5z3wFwnXsAk</addsrcrecordid><sourcetype>Open Access Repository</sourcetype><iscdi>true</iscdi><recordtype>article</recordtype><pqid>2311659511</pqid></control><display><type>article</type><title>Output correction factors for small static fields in megavoltage photon beams for seven ionization chambers in two orientations — perpendicular and parallel</title><source>MEDLINE</source><source>Access via Wiley Online Library</source><source>Alma/SFX Local Collection</source><creator>Casar, Božidar ; Gershkevitsh, Eduard ; Mendez, Ignasi ; Jurković, Slaven ; Saiful Huq, M.</creator><creatorcontrib>Casar, Božidar ; Gershkevitsh, Eduard ; Mendez, Ignasi ; Jurković, Slaven ; Saiful Huq, M.</creatorcontrib><description>Purpose
The goal of the present work was to provide a large set of detector‐specific output correction factors for seven small volume ionization chambers on two linear accelerators in four megavoltage photon beams utilizing perpendicular and parallel orientation of ionization chambers in the beam for nominal field sizes ranging from 0.5 cm2 × 0.5 cm2 to 10 cm2 × 10 cm2. The present study is the second part of an extensive research conducted by our group.
Methods
Output correction factors kQclin,Qreffclin,fref were experimentally determined on two linacs, Elekta Versa HD and Varian TrueBeam for 6 and 10 MV beams with and without flattening filter for nine square fields ranging from 0.5 cm2 × 0.5 cm2 to 10 cm2 × 10 cm2, for seven mini and micro ionization chambers, IBA CC04, IBA Razor, PTW 31016 3D PinPoint, PTW 31021 3D Semiflex, PTW 31022 3D PinPoint, PTW 31023 PinPoint, and SI Exradin A16. An Exradin W1 plastic scintillator and EBT3 radiochromic films were used as the reference detectors.
Results
For all ionization chambers, values of output correction factors kQclin,Qreffclin,fref were lower for parallel orientation compared to those obtained in the perpendicular orientation. Five ionization chambers from our study set, IBA Razor, PTW 31016 3D PinPoint, PTW 31022 3D PinPoint, PTW 31023 PinPoint, and SI Exradin A16, fulfill the requirement recommended in the TRS‐483 Code of Practice, that is, 0.95<kQclin,Qreffclin,fref<1.05, down to the field size 0.8 cm2 × 0.8 cm2, when they are positioned in parallel orientation; two of the ionization chambers, IBA Razor and PTW 31023 PinPoint, satisfy this condition down to the field size of 0.5 cm2 × 0.5 cm2.
Conclusions
The present paper provides experimental results of detector‐specific output correction factors for seven small volume ionization chambers. Output correction factors were determined in 6 and 10 MV photon beams with and without flattening filter down to the square field size of 0.5 cm2 × 0.5 cm2 for two orientations of ionization chambers — perpendicular and parallel. Our main finding is that output correction factors are smaller if they are determined in a parallel orientation compared to those obtained in a perpendicular orientation for all ionization chambers regardless of the photon beam energy, filtration, or linear accelerator being used. Based on our findings, we recommend using ionization chambers in parallel orientation, to minimize corrections in the experimental determination of field output factors. Latter holds even for field sizes below 1.0 cm2 × 1.0 cm2, whenever necessary corrections remain within 5%, which was the case for several ionization chambers from our set.
TRS‐483 recommended perpendicular orientation of ionization chambers for the determination of field output factors. The present study presents results for both perpendicular and parallel orientation of ionization chambers. When validated by other researchers, the present results for parallel orientation can be considered as a complementary dataset to those given in TRS‐483.</description><identifier>ISSN: 0094-2405</identifier><identifier>ISSN: 2473-4209</identifier><identifier>EISSN: 2473-4209</identifier><identifier>DOI: 10.1002/mp.13894</identifier><identifier>PMID: 31677278</identifier><language>eng</language><publisher>United States: John Wiley and Sons Inc</publisher><subject>COMPUTATIONAL AND EXPERIMENTAL DOSIMETRY ; ionization chamber ; orientation ; output correction factor ; Photons ; Radiometry - instrumentation ; small field ; Uncertainty</subject><ispartof>Medical physics (Lancaster), 2020-01, Vol.47 (1), p.242-259</ispartof><rights>2019 The Authors. Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.</rights><lds50>peer_reviewed</lds50><oa>free_for_read</oa><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-c4764-92e3911507fd389ebd4ff768f57edadcd7ca8beb7050f3cfaf6b08719e27a13d3</citedby><cites>FETCH-LOGICAL-c4764-92e3911507fd389ebd4ff768f57edadcd7ca8beb7050f3cfaf6b08719e27a13d3</cites></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><linktopdf>$$Uhttps://onlinelibrary.wiley.com/doi/pdf/10.1002%2Fmp.13894$$EPDF$$P50$$Gwiley$$Hfree_for_read</linktopdf><linktohtml>$$Uhttps://onlinelibrary.wiley.com/doi/full/10.1002%2Fmp.13894$$EHTML$$P50$$Gwiley$$Hfree_for_read</linktohtml><link.rule.ids>230,314,780,784,885,1417,27924,27925,45574,45575</link.rule.ids><backlink>$$Uhttps://www.ncbi.nlm.nih.gov/pubmed/31677278$$D View this record in MEDLINE/PubMed$$Hfree_for_read</backlink></links><search><creatorcontrib>Casar, Božidar</creatorcontrib><creatorcontrib>Gershkevitsh, Eduard</creatorcontrib><creatorcontrib>Mendez, Ignasi</creatorcontrib><creatorcontrib>Jurković, Slaven</creatorcontrib><creatorcontrib>Saiful Huq, M.</creatorcontrib><title>Output correction factors for small static fields in megavoltage photon beams for seven ionization chambers in two orientations — perpendicular and parallel</title><title>Medical physics (Lancaster)</title><addtitle>Med Phys</addtitle><description>Purpose
The goal of the present work was to provide a large set of detector‐specific output correction factors for seven small volume ionization chambers on two linear accelerators in four megavoltage photon beams utilizing perpendicular and parallel orientation of ionization chambers in the beam for nominal field sizes ranging from 0.5 cm2 × 0.5 cm2 to 10 cm2 × 10 cm2. The present study is the second part of an extensive research conducted by our group.
Methods
Output correction factors kQclin,Qreffclin,fref were experimentally determined on two linacs, Elekta Versa HD and Varian TrueBeam for 6 and 10 MV beams with and without flattening filter for nine square fields ranging from 0.5 cm2 × 0.5 cm2 to 10 cm2 × 10 cm2, for seven mini and micro ionization chambers, IBA CC04, IBA Razor, PTW 31016 3D PinPoint, PTW 31021 3D Semiflex, PTW 31022 3D PinPoint, PTW 31023 PinPoint, and SI Exradin A16. An Exradin W1 plastic scintillator and EBT3 radiochromic films were used as the reference detectors.
Results
For all ionization chambers, values of output correction factors kQclin,Qreffclin,fref were lower for parallel orientation compared to those obtained in the perpendicular orientation. Five ionization chambers from our study set, IBA Razor, PTW 31016 3D PinPoint, PTW 31022 3D PinPoint, PTW 31023 PinPoint, and SI Exradin A16, fulfill the requirement recommended in the TRS‐483 Code of Practice, that is, 0.95<kQclin,Qreffclin,fref<1.05, down to the field size 0.8 cm2 × 0.8 cm2, when they are positioned in parallel orientation; two of the ionization chambers, IBA Razor and PTW 31023 PinPoint, satisfy this condition down to the field size of 0.5 cm2 × 0.5 cm2.
Conclusions
The present paper provides experimental results of detector‐specific output correction factors for seven small volume ionization chambers. Output correction factors were determined in 6 and 10 MV photon beams with and without flattening filter down to the square field size of 0.5 cm2 × 0.5 cm2 for two orientations of ionization chambers — perpendicular and parallel. Our main finding is that output correction factors are smaller if they are determined in a parallel orientation compared to those obtained in a perpendicular orientation for all ionization chambers regardless of the photon beam energy, filtration, or linear accelerator being used. Based on our findings, we recommend using ionization chambers in parallel orientation, to minimize corrections in the experimental determination of field output factors. Latter holds even for field sizes below 1.0 cm2 × 1.0 cm2, whenever necessary corrections remain within 5%, which was the case for several ionization chambers from our set.
TRS‐483 recommended perpendicular orientation of ionization chambers for the determination of field output factors. The present study presents results for both perpendicular and parallel orientation of ionization chambers. When validated by other researchers, the present results for parallel orientation can be considered as a complementary dataset to those given in TRS‐483.</description><subject>COMPUTATIONAL AND EXPERIMENTAL DOSIMETRY</subject><subject>ionization chamber</subject><subject>orientation</subject><subject>output correction factor</subject><subject>Photons</subject><subject>Radiometry - instrumentation</subject><subject>small field</subject><subject>Uncertainty</subject><issn>0094-2405</issn><issn>2473-4209</issn><issn>2473-4209</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2020</creationdate><recordtype>article</recordtype><sourceid>24P</sourceid><sourceid>WIN</sourceid><sourceid>EIF</sourceid><recordid>eNp1kcFu1DAQhi0EoktB4gmQj1xS7DiJkwsSqmhBKiqHcrYm9njXyImD7WxVTn2Innk4noSwuxQ49DSH-f9vfs1PyEvOTjhj5ZthOuGi7apHZFVWUhRVybrHZMVYVxVlxeoj8iylr4yxRtTsKTkSvJGylO2K_Lic8zRnqkOMqLMLI7Wgc4iJ2hBpGsB7mjJkp6l16E2ibqQDrmEbfIY10mkT8uLqEYaDB7c40oXkvsMOqDcw9Bh3znwdaIgOx7zbJfrz9o5OGCccjdOzh0hhNHSCuBxG_5w8seATvjjMY_Ll7P3V6Yfi4vL84-m7i0JXsqmKrkTRcV4zac3yB-xNZa1sWltLNGC0kRraHnvJamaFtmCbnrWSd1hK4MKIY_J2z53mfkCjl3xLADVFN0C8UQGc-n8zuo1ah62SjAnZiAXw-gCI4duMKavBJY3ew4hhTqoUnDd1V3P-V6pjSCmivT_Dmfpdpxomtatzkb76N9a98E9_i6DYC66dx5sHQerT5z3wFwnXsAk</recordid><startdate>202001</startdate><enddate>202001</enddate><creator>Casar, Božidar</creator><creator>Gershkevitsh, Eduard</creator><creator>Mendez, Ignasi</creator><creator>Jurković, Slaven</creator><creator>Saiful Huq, M.</creator><general>John Wiley and Sons Inc</general><scope>24P</scope><scope>WIN</scope><scope>CGR</scope><scope>CUY</scope><scope>CVF</scope><scope>ECM</scope><scope>EIF</scope><scope>NPM</scope><scope>AAYXX</scope><scope>CITATION</scope><scope>7X8</scope><scope>5PM</scope></search><sort><creationdate>202001</creationdate><title>Output correction factors for small static fields in megavoltage photon beams for seven ionization chambers in two orientations — perpendicular and parallel</title><author>Casar, Božidar ; Gershkevitsh, Eduard ; Mendez, Ignasi ; Jurković, Slaven ; Saiful Huq, M.</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-c4764-92e3911507fd389ebd4ff768f57edadcd7ca8beb7050f3cfaf6b08719e27a13d3</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2020</creationdate><topic>COMPUTATIONAL AND EXPERIMENTAL DOSIMETRY</topic><topic>ionization chamber</topic><topic>orientation</topic><topic>output correction factor</topic><topic>Photons</topic><topic>Radiometry - instrumentation</topic><topic>small field</topic><topic>Uncertainty</topic><toplevel>peer_reviewed</toplevel><toplevel>online_resources</toplevel><creatorcontrib>Casar, Božidar</creatorcontrib><creatorcontrib>Gershkevitsh, Eduard</creatorcontrib><creatorcontrib>Mendez, Ignasi</creatorcontrib><creatorcontrib>Jurković, Slaven</creatorcontrib><creatorcontrib>Saiful Huq, M.</creatorcontrib><collection>Wiley Online Library Open Access</collection><collection>Wiley Online Library Free Content</collection><collection>Medline</collection><collection>MEDLINE</collection><collection>MEDLINE (Ovid)</collection><collection>MEDLINE</collection><collection>MEDLINE</collection><collection>PubMed</collection><collection>CrossRef</collection><collection>MEDLINE - Academic</collection><collection>PubMed Central (Full Participant titles)</collection><jtitle>Medical physics (Lancaster)</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Casar, Božidar</au><au>Gershkevitsh, Eduard</au><au>Mendez, Ignasi</au><au>Jurković, Slaven</au><au>Saiful Huq, M.</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>Output correction factors for small static fields in megavoltage photon beams for seven ionization chambers in two orientations — perpendicular and parallel</atitle><jtitle>Medical physics (Lancaster)</jtitle><addtitle>Med Phys</addtitle><date>2020-01</date><risdate>2020</risdate><volume>47</volume><issue>1</issue><spage>242</spage><epage>259</epage><pages>242-259</pages><issn>0094-2405</issn><issn>2473-4209</issn><eissn>2473-4209</eissn><abstract>Purpose
The goal of the present work was to provide a large set of detector‐specific output correction factors for seven small volume ionization chambers on two linear accelerators in four megavoltage photon beams utilizing perpendicular and parallel orientation of ionization chambers in the beam for nominal field sizes ranging from 0.5 cm2 × 0.5 cm2 to 10 cm2 × 10 cm2. The present study is the second part of an extensive research conducted by our group.
Methods
Output correction factors kQclin,Qreffclin,fref were experimentally determined on two linacs, Elekta Versa HD and Varian TrueBeam for 6 and 10 MV beams with and without flattening filter for nine square fields ranging from 0.5 cm2 × 0.5 cm2 to 10 cm2 × 10 cm2, for seven mini and micro ionization chambers, IBA CC04, IBA Razor, PTW 31016 3D PinPoint, PTW 31021 3D Semiflex, PTW 31022 3D PinPoint, PTW 31023 PinPoint, and SI Exradin A16. An Exradin W1 plastic scintillator and EBT3 radiochromic films were used as the reference detectors.
Results
For all ionization chambers, values of output correction factors kQclin,Qreffclin,fref were lower for parallel orientation compared to those obtained in the perpendicular orientation. Five ionization chambers from our study set, IBA Razor, PTW 31016 3D PinPoint, PTW 31022 3D PinPoint, PTW 31023 PinPoint, and SI Exradin A16, fulfill the requirement recommended in the TRS‐483 Code of Practice, that is, 0.95<kQclin,Qreffclin,fref<1.05, down to the field size 0.8 cm2 × 0.8 cm2, when they are positioned in parallel orientation; two of the ionization chambers, IBA Razor and PTW 31023 PinPoint, satisfy this condition down to the field size of 0.5 cm2 × 0.5 cm2.
Conclusions
The present paper provides experimental results of detector‐specific output correction factors for seven small volume ionization chambers. Output correction factors were determined in 6 and 10 MV photon beams with and without flattening filter down to the square field size of 0.5 cm2 × 0.5 cm2 for two orientations of ionization chambers — perpendicular and parallel. Our main finding is that output correction factors are smaller if they are determined in a parallel orientation compared to those obtained in a perpendicular orientation for all ionization chambers regardless of the photon beam energy, filtration, or linear accelerator being used. Based on our findings, we recommend using ionization chambers in parallel orientation, to minimize corrections in the experimental determination of field output factors. Latter holds even for field sizes below 1.0 cm2 × 1.0 cm2, whenever necessary corrections remain within 5%, which was the case for several ionization chambers from our set.
TRS‐483 recommended perpendicular orientation of ionization chambers for the determination of field output factors. The present study presents results for both perpendicular and parallel orientation of ionization chambers. When validated by other researchers, the present results for parallel orientation can be considered as a complementary dataset to those given in TRS‐483.</abstract><cop>United States</cop><pub>John Wiley and Sons Inc</pub><pmid>31677278</pmid><doi>10.1002/mp.13894</doi><tpages>18</tpages><oa>free_for_read</oa></addata></record> |
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| subjects | COMPUTATIONAL AND EXPERIMENTAL DOSIMETRY ionization chamber orientation output correction factor Photons Radiometry - instrumentation small field Uncertainty |
| title | Output correction factors for small static fields in megavoltage photon beams for seven ionization chambers in two orientations — perpendicular and parallel |
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