Matches in SemOpenAlex for { <https://semopenalex.org/work/W330054518> ?p ?o ?g. }
Showing items 1 to 83 of
83
with 100 items per page.
- W330054518 abstract "Introduction: Around 1.000 people are diagnosed with head and neck cancer in Sweden every year. Radiotherapy is often used to treat these tumors. When irradiating patients in the head and neck area there are some problems. One of these problems is the large difference in density between the oral tissue and dental materials. Another problem is the image artifacts due to high-density materials in the CT-images used for radiotherapy treatment planning. These effects must be studied to assure that an optimal treatment is givenMaterials and methods: Dental materials were placed at 37 mm depth in a custom built water filled phantom and irradiated using photon beam energy of 6 MV. TLD and a compact ion chamber were used for obtaining depth dose curves before and after the high-density dental material at clinical relevant depths. Monte Carlo simulations were used for reference. Monte Carlo simulations were obtained using the EGSnrc user code DOSXYZnrc. The dental materials studied were composite, porcelain, titanium and a 75 % gold alloy. The sizes of the dental material were 1 cm3 except for the gold alloy that was 0.26 cm3. A computer generated phantom equal to the real phantom was created in the treatment planning system (TPS). The TPS used in this study was the Oncentra Master Plan v1.5 (Nucletron B.V. Veenendaal, The Netherlands). Two dose calculation algorithms have been evaluated, the pencil beam and the collapsed cone. Two different CT scanners have been evaluated in this study.Results: The compact ion chamber gave a much better agreement with Monte Carlo simulations than the TLD. An overestimation of 23 % in absorbed dose was found just before the gold alloy compared to the result calculated by the TPS. Also an underestimation of dose was found at 5 cm depth for the gold cavity. Differences of up to 8.8 % in absorbed dose were found between the two calculation algorithms. Differences of up to 700 HU was found between the CT-scanned dental materials and the Hounsfield scale implemented in the TPS to calculate electron density. 3.0 % difference in absorbed dose was found at 5 cm depth for the gold alloy between the two different CT-scanners.Conclusions: The 23 % difference in dose before the gold cavity due to backscattered contaminating electrons cannot be neglected. The use of bite-blocks can minimize the dose to oral tissue due to these electrons. The collapsed cone is the preferable dose calculation algorithm since it calculates dose to the actual medium. CT-scanners must be evaluated before commissioning to find the most suitable filters and reconstruction algorithms to minimize image artifacts. Limitations in the TPS such as assigning electron density and maximum density handled leads to underestimations and overestimations of absorbed dose after high-density cavities" @default.
- W330054518 created "2016-06-24" @default.
- W330054518 creator A5009290046 @default.
- W330054518 date "2007-01-01" @default.
- W330054518 modified "2023-09-27" @default.
- W330054518 title "Absorbed dose distributions in the vicinity of high-density materials in head and neck radiotherapy A quantitative comparison between measurements, Monte Carlo simulations and treatment planning system" @default.
- W330054518 hasPublicationYear "2007" @default.
- W330054518 type Work @default.
- W330054518 sameAs 330054518 @default.
- W330054518 citedByCount "0" @default.
- W330054518 crossrefType "journal-article" @default.
- W330054518 hasAuthorship W330054518A5009290046 @default.
- W330054518 hasConcept C104293457 @default.
- W330054518 hasConcept C105795698 @default.
- W330054518 hasConcept C120665830 @default.
- W330054518 hasConcept C121332964 @default.
- W330054518 hasConcept C126838900 @default.
- W330054518 hasConcept C145148216 @default.
- W330054518 hasConcept C151770136 @default.
- W330054518 hasConcept C168834538 @default.
- W330054518 hasConcept C180048950 @default.
- W330054518 hasConcept C192562407 @default.
- W330054518 hasConcept C19499675 @default.
- W330054518 hasConcept C19527891 @default.
- W330054518 hasConcept C198291218 @default.
- W330054518 hasConcept C201645570 @default.
- W330054518 hasConcept C2776530083 @default.
- W330054518 hasConcept C2989005 @default.
- W330054518 hasConcept C33923547 @default.
- W330054518 hasConcept C41008148 @default.
- W330054518 hasConcept C509974204 @default.
- W330054518 hasConcept C62520636 @default.
- W330054518 hasConcept C71924100 @default.
- W330054518 hasConcept C75088862 @default.
- W330054518 hasConceptScore W330054518C104293457 @default.
- W330054518 hasConceptScore W330054518C105795698 @default.
- W330054518 hasConceptScore W330054518C120665830 @default.
- W330054518 hasConceptScore W330054518C121332964 @default.
- W330054518 hasConceptScore W330054518C126838900 @default.
- W330054518 hasConceptScore W330054518C145148216 @default.
- W330054518 hasConceptScore W330054518C151770136 @default.
- W330054518 hasConceptScore W330054518C168834538 @default.
- W330054518 hasConceptScore W330054518C180048950 @default.
- W330054518 hasConceptScore W330054518C192562407 @default.
- W330054518 hasConceptScore W330054518C19499675 @default.
- W330054518 hasConceptScore W330054518C19527891 @default.
- W330054518 hasConceptScore W330054518C198291218 @default.
- W330054518 hasConceptScore W330054518C201645570 @default.
- W330054518 hasConceptScore W330054518C2776530083 @default.
- W330054518 hasConceptScore W330054518C2989005 @default.
- W330054518 hasConceptScore W330054518C33923547 @default.
- W330054518 hasConceptScore W330054518C41008148 @default.
- W330054518 hasConceptScore W330054518C509974204 @default.
- W330054518 hasConceptScore W330054518C62520636 @default.
- W330054518 hasConceptScore W330054518C71924100 @default.
- W330054518 hasConceptScore W330054518C75088862 @default.
- W330054518 hasLocation W3300545181 @default.
- W330054518 hasOpenAccess W330054518 @default.
- W330054518 hasPrimaryLocation W3300545181 @default.
- W330054518 hasRelatedWork W1969125839 @default.
- W330054518 hasRelatedWork W1975679479 @default.
- W330054518 hasRelatedWork W1979633493 @default.
- W330054518 hasRelatedWork W1981892371 @default.
- W330054518 hasRelatedWork W1985277985 @default.
- W330054518 hasRelatedWork W2002961068 @default.
- W330054518 hasRelatedWork W2004886510 @default.
- W330054518 hasRelatedWork W2016088369 @default.
- W330054518 hasRelatedWork W2042442161 @default.
- W330054518 hasRelatedWork W2059084527 @default.
- W330054518 hasRelatedWork W2063552505 @default.
- W330054518 hasRelatedWork W2083190666 @default.
- W330054518 hasRelatedWork W2104166410 @default.
- W330054518 hasRelatedWork W2155239321 @default.
- W330054518 hasRelatedWork W2171450366 @default.
- W330054518 hasRelatedWork W2464990297 @default.
- W330054518 hasRelatedWork W2468467130 @default.
- W330054518 hasRelatedWork W2472963014 @default.
- W330054518 hasRelatedWork W2744277208 @default.
- W330054518 hasRelatedWork W3010324055 @default.
- W330054518 isParatext "false" @default.
- W330054518 isRetracted "false" @default.
- W330054518 magId "330054518" @default.
- W330054518 workType "article" @default.