FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W111719795> ?p ?o ?g. }

• W111719795 abstract "The effects of tumour motion during radiation therapy delivery have been widely investigated. Motion effects have become increasingly important with the introduction of dynamic radiotherapy delivery modalities such as enhanced dynamic wedges (EDWs) and intensity modulated radiation therapy (IMRT) where a dynamically collimated radiation beam is delivered to the moving target, resulting in dose blurring and interplay effects which are a consequence of the combined tumor and beam motion. Prior to this work, reported studies on the EDW based interplay effects have been restricted to the use of experimental methods for assessing single-field non-fractionated treatments. In this work, the interplay effects have been investigated for EDW treatments. Single and multiple field treatments have been studied using experimental and Monte Carlo (MC) methods.Initially this work experimentally studies interplay effects for single-field non-fractionated EDW treatments, using radiation dosimetry systems placed on a sinusoidaly moving platform. A number of wedge angles (60o, 45o and 15o), field sizes (20 × 20, 10 × 10 and 5 × 5 cm2), amplitudes (10-40 mm in step of 10 mm) and periods (2 s, 3 s, 4.5 s and 6 s) of tumor motion are analysed (using gamma analysis) for parallel and perpendicular motions (where the tumor and jaw motions are either parallel or perpendicular to each other). For parallel motion it was found that both the amplitude and period of tumor motion affect the interplay, this becomes more prominent where the collimator tumor speeds become identical. For perpendicular motion the amplitude of tumor motion is the dominant factor where as varying the period of tumor motion has no observable effect on the dose distribution. The wedge angle results suggest that the use of a large wedge angle generates greater dose variation for both parallel and perpendicular motions. The use of small field size with a large tumor motion results in the loss of wedged dose distribution for both parallel and perpendicular motion. From these single field measurements a motion amplitude and period have been identified which show the poorest agreement between the target motion and dynamic delivery and these are used as the „worst case motion parameters.. The experimental work is then extended to multiple-field fractionated treatments. Here a number of pre-existing, multiple–field, wedged lung plans are delivered to the radiation dosimetry systems, employing the worst case motion parameters. Moreover a four field EDW lung plan (using a 4D CT data set) is delivered to the IMRT quality control phantom with dummy tumor insert over four fractions using the worst case parameters i.e. 40 mm amplitude and 6 s period values. The analysis of the film doses using gamma analysis at 3%-3mm indicate the non averaging of the interplay effects for this particular study with a gamma pass rate of 49%. To enable Monte Carlo modelling of the problem, the DYNJAWS component module (CM) of the BEAMnrc user code is validated and automated. DYNJAWS has been recently introduced to model the dynamic wedges. DYNJAWS is therefore commissioned for 6 MV and 10 MV photon energies. It is shown that this CM can accurately model the EDWs for a number of wedge angles and field sizes. The dynamic and step and shoot modes of the CM are compared for their accuracy in modelling the EDW. It is shown that dynamic mode is more accurate. An automation of the DYNJAWS specific input file has been carried out. This file specifies the probability of selection of a subfield and the respective jaw coordinates. This automation simplifies the generation of the BEAMnrc input files for DYNJAWS. The DYNJAWS commissioned model is then used to study multiple field EDW treatments using MC methods. The 4D CT data of an IMRT phantom with the dummy tumor is used to produce a set of Monte Carlo simulation phantoms, onto which the delivery of single field and multiple field EDW treatments is simulated. A number of static and motion multiple field EDW plans have been simulated. The comparison of dose volume histograms (DVHs) and gamma volume histograms (GVHs) for four field EDW treatments (where the collimator and patient motion is in the same direction) using small (15o) and large wedge angles (60o) indicates a greater mismatch between the static and motion cases for the large wedge angle. Finally, to use gel dosimetry as a validation tool, a new technique called the „zero-scan method. is developed for reading the gel dosimeters with x-ray computed tomography (CT). It has been shown that multiple scans of a gel dosimeter (in this case 360 scans) can be used to reconstruct a zero scan image. This zero scan image has a similar precision to an image obtained by averaging the CT images, without the additional dose delivered by the CT scans. In this investigation the interplay effects have been studied for single and multiple field fractionated EDW treatments using experimental and Monte Carlo methods. For using the Monte Carlo methods the DYNJAWS component module of the BEAMnrc code has been validated and automated and further used to study the interplay for multiple field EDW treatments. Zero-scan method, a new gel dosimetry readout technique has been developed for reading the gel images using x-ray CT without losing the precision and accuracy." @default.
• W111719795 created "2016-06-24" @default.
• W111719795 creator A5054671946 @default.
• W111719795 date "2012-01-01" @default.
• W111719795 modified "2023-09-27" @default.
• W111719795 title "Monte Carlo simulations of dynamic radiotherapy treatments" @default.
• W111719795 cites W1563809809 @default.
• W111719795 cites W1963650567 @default.
• W111719795 cites W1963882488 @default.
• W111719795 cites W1966234893 @default.
• W111719795 cites W1966527915 @default.
• W111719795 cites W1975040346 @default.
• W111719795 cites W1976939264 @default.
• W111719795 cites W1978712731 @default.
• W111719795 cites W1981989535 @default.
• W111719795 cites W1984213891 @default.
• W111719795 cites W1990405815 @default.
• W111719795 cites W1998759803 @default.
• W111719795 cites W1998828795 @default.
• W111719795 cites W1998857957 @default.
• W111719795 cites W1999068144 @default.
• W111719795 cites W2000655971 @default.
• W111719795 cites W2002236639 @default.
• W111719795 cites W2005287757 @default.
• W111719795 cites W2012270212 @default.
• W111719795 cites W2016219306 @default.
• W111719795 cites W2017828111 @default.
• W111719795 cites W2023487416 @default.
• W111719795 cites W2023903796 @default.
• W111719795 cites W2030700189 @default.
• W111719795 cites W2033631797 @default.
• W111719795 cites W2047595261 @default.
• W111719795 cites W2055439200 @default.
• W111719795 cites W2057186248 @default.
• W111719795 cites W2066585524 @default.
• W111719795 cites W2074967925 @default.
• W111719795 cites W2083976177 @default.
• W111719795 cites W2087859424 @default.
• W111719795 cites W2089639322 @default.
• W111719795 cites W2089667970 @default.
• W111719795 cites W2091361931 @default.
• W111719795 cites W2104338903 @default.
• W111719795 cites W2107284620 @default.
• W111719795 cites W2112586577 @default.
• W111719795 cites W2115132733 @default.
• W111719795 cites W2116272759 @default.
• W111719795 cites W2116923242 @default.
• W111719795 cites W2124732328 @default.
• W111719795 cites W2127480863 @default.
• W111719795 cites W2155284677 @default.
• W111719795 cites W2163242083 @default.
• W111719795 cites W2163827108 @default.
• W111719795 cites W2163894579 @default.
• W111719795 cites W2164883161 @default.
• W111719795 cites W2167767036 @default.
• W111719795 cites W2168647567 @default.
• W111719795 cites W2334379273 @default.
• W111719795 cites W2346397638 @default.
• W111719795 cites W3159004246 @default.
• W111719795 cites W6587533 @default.
• W111719795 hasPublicationYear "2012" @default.
• W111719795 type Work @default.
• W111719795 sameAs 111719795 @default.
• W111719795 citedByCount "2" @default.
• W111719795 countsByYear W1117197952016 @default.
• W111719795 countsByYear W1117197952017 @default.
• W111719795 crossrefType "dissertation" @default.
• W111719795 hasAuthorship W111719795A5054671946 @default.
• W111719795 hasConcept C104114177 @default.
• W111719795 hasConcept C105795698 @default.
• W111719795 hasConcept C120665830 @default.
• W111719795 hasConcept C121332964 @default.
• W111719795 hasConcept C126838900 @default.
• W111719795 hasConcept C168834538 @default.
• W111719795 hasConcept C180205008 @default.
• W111719795 hasConcept C19499675 @default.
• W111719795 hasConcept C199631012 @default.
• W111719795 hasConcept C2524010 @default.
• W111719795 hasConcept C2779200277 @default.
• W111719795 hasConcept C2989005 @default.
• W111719795 hasConcept C30475298 @default.
• W111719795 hasConcept C33923547 @default.
• W111719795 hasConcept C34445779 @default.
• W111719795 hasConcept C47422493 @default.
• W111719795 hasConcept C509974204 @default.
• W111719795 hasConcept C520434653 @default.
• W111719795 hasConcept C71924100 @default.
• W111719795 hasConcept C74650414 @default.
• W111719795 hasConcept C75088862 @default.
• W111719795 hasConceptScore W111719795C104114177 @default.
• W111719795 hasConceptScore W111719795C105795698 @default.
• W111719795 hasConceptScore W111719795C120665830 @default.
• W111719795 hasConceptScore W111719795C121332964 @default.
• W111719795 hasConceptScore W111719795C126838900 @default.
• W111719795 hasConceptScore W111719795C168834538 @default.
• W111719795 hasConceptScore W111719795C180205008 @default.
• W111719795 hasConceptScore W111719795C19499675 @default.
• W111719795 hasConceptScore W111719795C199631012 @default.
• W111719795 hasConceptScore W111719795C2524010 @default.
• W111719795 hasConceptScore W111719795C2779200277 @default.

• next