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Characterization of a 6 MV photon beam in terms of primary and scattered dose components
The purpose of this work was to partition the 6 MV photon beam of a Philips SL75-5 linear accelerator into primary and scattered dose components in water. The two quantities that are necessary to define the primary beam component are a reference dose DR and a primary linear attenuation coefficient &...
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| Format: | Thesis |
| Language: | English |
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Division of Medical Physics
2014
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| _version_ | 1867613246199955456 |
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| access_status_str | Open Access |
| author | Trauernicht, Christoph Jan |
| author2 | Hering, E R |
| author_browse | Hering, E R Trauernicht, Christoph Jan |
| author_facet | Hering, E R Trauernicht, Christoph Jan |
| author_sort | Trauernicht, Christoph Jan |
| collection | Thesis |
| description | The purpose of this work was to partition the 6 MV photon beam of a Philips SL75-5 linear accelerator into primary and scattered dose components in water. The two quantities that are necessary to define the primary beam component are a reference dose DR and a primary linear attenuation coefficient μ 0. DR describes the magnitude of the primary dose as a fraction of the total dose in a reference field at a reference depth, while μ 0 describes how the primary dose changes with depth in a medium. The scattered component is the difference between the primary and total dose. μ 0 for the beam in water was determined in four different ways, namely through the extrapolation of measured TMRs to zero field size, through linear attenuation measurements, through the fit of a convolution model to CAPDD data and through a method involving a central axis attenuator. The primary dose component was determined in two ways, namely by the extrapolation of the phantom scatter correction factor to zero field size and also by the central axis attenuator method. μ 0 varied from 0.0445 cm-1 to 0.0469 cm-1 with an average of 0.0455 +- 0.0012 cm-1. DR for a 10 cm x 10 cm field at the depth of maximum dose was found to vary between 0.933 Gy/ 100 MU and 0.935 Gy/ 100 MU, with an average of 0.934 Gy/ 100 MU. These values agree very well with values published in the literature. It has thus been shown that the 6 MV photon beam is separable into primary and scattered dose components. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/2801 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:33:05.164Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2014 |
| publishDateRange | 2014 |
| publishDateSort | 2014 |
| publisher | Division of Medical Physics |
| publisherStr | Division of Medical Physics |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/2801 Characterization of a 6 MV photon beam in terms of primary and scattered dose components Trauernicht, Christoph Jan Hering, E R Nieto-Camero, Jaime Medicine The purpose of this work was to partition the 6 MV photon beam of a Philips SL75-5 linear accelerator into primary and scattered dose components in water. The two quantities that are necessary to define the primary beam component are a reference dose DR and a primary linear attenuation coefficient μ 0. DR describes the magnitude of the primary dose as a fraction of the total dose in a reference field at a reference depth, while μ 0 describes how the primary dose changes with depth in a medium. The scattered component is the difference between the primary and total dose. μ 0 for the beam in water was determined in four different ways, namely through the extrapolation of measured TMRs to zero field size, through linear attenuation measurements, through the fit of a convolution model to CAPDD data and through a method involving a central axis attenuator. The primary dose component was determined in two ways, namely by the extrapolation of the phantom scatter correction factor to zero field size and also by the central axis attenuator method. μ 0 varied from 0.0445 cm-1 to 0.0469 cm-1 with an average of 0.0455 +- 0.0012 cm-1. DR for a 10 cm x 10 cm field at the depth of maximum dose was found to vary between 0.933 Gy/ 100 MU and 0.935 Gy/ 100 MU, with an average of 0.934 Gy/ 100 MU. These values agree very well with values published in the literature. It has thus been shown that the 6 MV photon beam is separable into primary and scattered dose components. 2014-07-28T11:10:08Z 2014-07-28T11:10:08Z 2009 Master Thesis Masters MSc http://hdl.handle.net/11427/2801 eng application/pdf Division of Medical Physics Faculty of Health Sciences University of Cape Town |
| spellingShingle | Medicine Trauernicht, Christoph Jan Characterization of a 6 MV photon beam in terms of primary and scattered dose components |
| thesis_degree_str | Master's |
| title | Characterization of a 6 MV photon beam in terms of primary and scattered dose components |
| title_full | Characterization of a 6 MV photon beam in terms of primary and scattered dose components |
| title_fullStr | Characterization of a 6 MV photon beam in terms of primary and scattered dose components |
| title_full_unstemmed | Characterization of a 6 MV photon beam in terms of primary and scattered dose components |
| title_short | Characterization of a 6 MV photon beam in terms of primary and scattered dose components |
| title_sort | characterization of a 6 mv photon beam in terms of primary and scattered dose components |
| topic | Medicine |
| url | http://hdl.handle.net/11427/2801 |
| work_keys_str_mv | AT trauernichtchristophjan characterizationofa6mvphotonbeamintermsofprimaryandscattereddosecomponents |