Modelling normal tissue toxicity in pancreatic chemoradiotherapy
<p>The relationship between radiation dose and toxicity in pancreatic chemoradiotherapy is not well understood. Clinically, excessive normal tissue toxicity is avoided by placing a constraint on the volume of the organ receiving a dose above a threshold. Dose-volume constraints lack spatial...
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| Formaat: | Thesis |
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2018
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| _version_ | 1826316690280939520 |
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| author | Witztum, A |
| author2 | Hawkins, M |
| author_facet | Hawkins, M Witztum, A |
| author_sort | Witztum, A |
| collection | OXFORD |
| description | <p>The relationship between radiation dose and toxicity in pancreatic chemoradiotherapy is not well understood. Clinically, excessive normal tissue toxicity is avoided by placing a constraint on the volume of the organ receiving a dose above a threshold. Dose-volume constraints lack spatial information which may be important in determining normal tissue response.</p> <p>Spatial dose distribution information can be found in dose-surface maps (DSMs). A dose-surface map is a 2-dimensional virtual unwrapping of the surface dose of on organ. Due to the complex geometry of the duodenum, previous methods for unwrapping tubular organs for spatial toxicity modelling are insuficient. A geometrically robust method for producing dose-surface maps, specifically for the duodenum, was created in order to characterise the spatial dose distribution.</p> <p>This unwrapping methodology was shown to be generalisable to simple organs such as the stomach, and extendable to more complex organs such as the bronchial tree. A graphical user interface to create dose-surface maps from organs in commercial treatment planning systems was also demonstrated.</p> <p>Duodenal and stomach dose-surface maps were created for patients from two pancreatic chemoradiotherapy trials, ARCII and SCALOP, treating locally-advanced pancreatic cancer (LAPC). New spatial features were extracted from dose-surface maps and their correlation with upper-gastrointestinal toxicity quantified and compared to traditional dose-volume metrics. The predictive power of some of these new metrics were found to be superior to dose-volume metrics in the stomach, but no significant correlation was found in the duodenum.</p> <p>Duodenal motion throughout treatment occurs both due to respiratory motion and peristalsis. On board imaging using cone-beam CT (CBCT) during individual treatment fractions shows that interfraction variability is non-systematic and cannot be predicted. While abdominal compression is able to restrict some interfraction motion, it is unable to control peristaltic changes. Accumulated duodenal dose-surface maps from these images were created to investigate the differences between the planned and delivered dose.</p> |
| first_indexed | 2024-03-06T22:13:31Z |
| format | Thesis |
| id | oxford-uuid:52a0b44b-84d4-444e-9f2a-fdbe0fc29edf |
| institution | University of Oxford |
| last_indexed | 2024-12-09T03:49:28Z |
| publishDate | 2018 |
| record_format | dspace |
| spelling | oxford-uuid:52a0b44b-84d4-444e-9f2a-fdbe0fc29edf2024-12-08T12:45:08ZModelling normal tissue toxicity in pancreatic chemoradiotherapyThesishttp://purl.org/coar/resource_type/c_db06uuid:52a0b44b-84d4-444e-9f2a-fdbe0fc29edfORA Deposit2018Witztum, AHawkins, MVan den Heuvel, FGeorge, B<p>The relationship between radiation dose and toxicity in pancreatic chemoradiotherapy is not well understood. Clinically, excessive normal tissue toxicity is avoided by placing a constraint on the volume of the organ receiving a dose above a threshold. Dose-volume constraints lack spatial information which may be important in determining normal tissue response.</p> <p>Spatial dose distribution information can be found in dose-surface maps (DSMs). A dose-surface map is a 2-dimensional virtual unwrapping of the surface dose of on organ. Due to the complex geometry of the duodenum, previous methods for unwrapping tubular organs for spatial toxicity modelling are insuficient. A geometrically robust method for producing dose-surface maps, specifically for the duodenum, was created in order to characterise the spatial dose distribution.</p> <p>This unwrapping methodology was shown to be generalisable to simple organs such as the stomach, and extendable to more complex organs such as the bronchial tree. A graphical user interface to create dose-surface maps from organs in commercial treatment planning systems was also demonstrated.</p> <p>Duodenal and stomach dose-surface maps were created for patients from two pancreatic chemoradiotherapy trials, ARCII and SCALOP, treating locally-advanced pancreatic cancer (LAPC). New spatial features were extracted from dose-surface maps and their correlation with upper-gastrointestinal toxicity quantified and compared to traditional dose-volume metrics. The predictive power of some of these new metrics were found to be superior to dose-volume metrics in the stomach, but no significant correlation was found in the duodenum.</p> <p>Duodenal motion throughout treatment occurs both due to respiratory motion and peristalsis. On board imaging using cone-beam CT (CBCT) during individual treatment fractions shows that interfraction variability is non-systematic and cannot be predicted. While abdominal compression is able to restrict some interfraction motion, it is unable to control peristaltic changes. Accumulated duodenal dose-surface maps from these images were created to investigate the differences between the planned and delivered dose.</p> |
| spellingShingle | Witztum, A Modelling normal tissue toxicity in pancreatic chemoradiotherapy |
| title | Modelling normal tissue toxicity in pancreatic chemoradiotherapy |
| title_full | Modelling normal tissue toxicity in pancreatic chemoradiotherapy |
| title_fullStr | Modelling normal tissue toxicity in pancreatic chemoradiotherapy |
| title_full_unstemmed | Modelling normal tissue toxicity in pancreatic chemoradiotherapy |
| title_short | Modelling normal tissue toxicity in pancreatic chemoradiotherapy |
| title_sort | modelling normal tissue toxicity in pancreatic chemoradiotherapy |
| work_keys_str_mv | AT witztuma modellingnormaltissuetoxicityinpancreaticchemoradiotherapy |