Matches in SemOpenAlex for { <https://semopenalex.org/work/W2340377732> ?p ?o ?g. }
- W2340377732 endingPage "2484" @default.
- W2340377732 startingPage "2476" @default.
- W2340377732 abstract "Purpose: PTW's Octavius 1000 SRS array performs IMRT quality assurance (QA) measurements with liquid-filled ionization chambers (LICs) to allow closer detector spacing and higher resolution, compared to air-filled QA devices. However, reduced ion mobility in LICs relative to air leads to increased ion recombination effects and reduced collection efficiencies that are dependent on Linac pulse frequency and pulse dose. These pulse parameters are variable during an IMRT delivery, which affects QA results. In this study, (1) 1000 SRS collection efficiencies were measured as a function of pulse frequency and pulse dose, (2) two methods were developed to correct changes in collection efficiencies during IMRT QA measurements, and the effects of these corrections on QA pass rates were compared. Methods: To obtain collection efficiencies, the OCTAVIUS 1000 SRS was used to measure open fields of varying pulse frequency, pulse dose, and beam energy with results normalized to air-filled chamber measurements. Changes in ratios of 1000 SRS to chamber measured dose were attributed to changing collection efficiencies, which were then correlated to pulse parameters using regression analysis. The usefulness of the derived corrections was then evaluated using 6 MV and 10FFF SBRT RapidArc plans delivered to the OCTAVIUS 4D system using a TrueBeam (Varian Medical Systems) linear accelerator equipped with a high definition multileaf collimator. For the first correction, matlab software was developed that calculates pulse frequency and pulse dose for each detector, using measurement and DICOM RT Plan files. Pulse information is converted to collection efficiency, and measurements are corrected by multiplying detector dose by ratios of calibration to measured collection efficiencies. For the second correction the MU/min in the daily 1000 SRS calibration was chosen to match the average MU/min of the volumetric modulated arc therapy plan. Effects of the two corrections on QA results were examined by performing 3D gamma analysis comparing predicted to measured dose, with and without corrections. Results: Collection efficiencies correlated linearly to pulse dose, while correlations with pulse frequency were less defined, generally increasing as pulse frequency decreased. After complex matlab corrections, average 3D gamma pass rates improved by [0.07%,0.40%,1.17%] for 6 MV and [0.29%,1.40%,4.57%] for 10FFF using [3%/3 mm,2%/2 mm,1%/1 mm] criteria. Maximum changes in gamma pass rates were [0.43%,1.63%,3.05%] for 6 MV and [1.00%,4.80%,11.2%] for 10FFF using [3%/3 mm,2%/2 mm,1%/1 mm] criteria. On average, pass rates of simple daily calibration corrections were within 1% of complex matlab corrections. Conclusions: OCTAVIUS 1000 SRS ion recombination effects have little effect on 6 MV measurements. However, the effect could potentially be clinically significant for higher pulse dose unflattened beams when using tighter gamma tolerances, especially when small aperture sizes are used, as is common for SRS/SBRT. In addition, ion recombination effects are strongly correlated to changing MU/min, therefore MU/min used in daily 1000 SRS calibrations should be matched to the expected average MU/min of the IMRT plan." @default.
- W2340377732 created "2016-06-24" @default.
- W2340377732 creator A5008643015 @default.
- W2340377732 creator A5038911746 @default.
- W2340377732 creator A5042756485 @default.
- W2340377732 creator A5064515494 @default.
- W2340377732 creator A5068196186 @default.
- W2340377732 creator A5091399765 @default.
- W2340377732 date "2016-04-22" @default.
- W2340377732 modified "2023-10-16" @default.
- W2340377732 title "Investigating ion recombination effects in a liquid-filled ionization chamber array used for IMRT QA measurements" @default.
- W2340377732 cites W1966689157 @default.
- W2340377732 cites W1967121735 @default.
- W2340377732 cites W1967257519 @default.
- W2340377732 cites W1967798147 @default.
- W2340377732 cites W1980268171 @default.
- W2340377732 cites W1981199972 @default.
- W2340377732 cites W1985788305 @default.
- W2340377732 cites W2013858895 @default.
- W2340377732 cites W2026350275 @default.
- W2340377732 cites W2026711376 @default.
- W2340377732 cites W2029282270 @default.
- W2340377732 cites W2031520254 @default.
- W2340377732 cites W2032961327 @default.
- W2340377732 cites W2061033945 @default.
- W2340377732 cites W2075758052 @default.
- W2340377732 cites W2101983797 @default.
- W2340377732 cites W2108445644 @default.
- W2340377732 cites W2128631013 @default.
- W2340377732 cites W2129402896 @default.
- W2340377732 cites W2136706275 @default.
- W2340377732 cites W2165767756 @default.
- W2340377732 doi "https://doi.org/10.1118/1.4946822" @default.
- W2340377732 hasPubMedId "https://pubmed.ncbi.nlm.nih.gov/27147358" @default.
- W2340377732 hasPublicationYear "2016" @default.
- W2340377732 type Work @default.
- W2340377732 sameAs 2340377732 @default.
- W2340377732 citedByCount "6" @default.
- W2340377732 countsByYear W23403777322017 @default.
- W2340377732 countsByYear W23403777322018 @default.
- W2340377732 countsByYear W23403777322019 @default.
- W2340377732 countsByYear W23403777322020 @default.
- W2340377732 countsByYear W23403777322021 @default.
- W2340377732 crossrefType "journal-article" @default.
- W2340377732 hasAuthorship W2340377732A5008643015 @default.
- W2340377732 hasAuthorship W2340377732A5038911746 @default.
- W2340377732 hasAuthorship W2340377732A5042756485 @default.
- W2340377732 hasAuthorship W2340377732A5064515494 @default.
- W2340377732 hasAuthorship W2340377732A5068196186 @default.
- W2340377732 hasAuthorship W2340377732A5091399765 @default.
- W2340377732 hasBestOaLocation W23403777322 @default.
- W2340377732 hasConcept C120665830 @default.
- W2340377732 hasConcept C121332964 @default.
- W2340377732 hasConcept C145148216 @default.
- W2340377732 hasConcept C151770136 @default.
- W2340377732 hasConcept C161471255 @default.
- W2340377732 hasConcept C165838908 @default.
- W2340377732 hasConcept C168834538 @default.
- W2340377732 hasConcept C180048950 @default.
- W2340377732 hasConcept C192562407 @default.
- W2340377732 hasConcept C198291218 @default.
- W2340377732 hasConcept C2779200277 @default.
- W2340377732 hasConcept C2780167933 @default.
- W2340377732 hasConcept C2780271382 @default.
- W2340377732 hasConcept C2989005 @default.
- W2340377732 hasConcept C34445779 @default.
- W2340377732 hasConcept C520434653 @default.
- W2340377732 hasConcept C62520636 @default.
- W2340377732 hasConcept C63007395 @default.
- W2340377732 hasConcept C71924100 @default.
- W2340377732 hasConcept C75088862 @default.
- W2340377732 hasConcept C94915269 @default.
- W2340377732 hasConceptScore W2340377732C120665830 @default.
- W2340377732 hasConceptScore W2340377732C121332964 @default.
- W2340377732 hasConceptScore W2340377732C145148216 @default.
- W2340377732 hasConceptScore W2340377732C151770136 @default.
- W2340377732 hasConceptScore W2340377732C161471255 @default.
- W2340377732 hasConceptScore W2340377732C165838908 @default.
- W2340377732 hasConceptScore W2340377732C168834538 @default.
- W2340377732 hasConceptScore W2340377732C180048950 @default.
- W2340377732 hasConceptScore W2340377732C192562407 @default.
- W2340377732 hasConceptScore W2340377732C198291218 @default.
- W2340377732 hasConceptScore W2340377732C2779200277 @default.
- W2340377732 hasConceptScore W2340377732C2780167933 @default.
- W2340377732 hasConceptScore W2340377732C2780271382 @default.
- W2340377732 hasConceptScore W2340377732C2989005 @default.
- W2340377732 hasConceptScore W2340377732C34445779 @default.
- W2340377732 hasConceptScore W2340377732C520434653 @default.
- W2340377732 hasConceptScore W2340377732C62520636 @default.
- W2340377732 hasConceptScore W2340377732C63007395 @default.
- W2340377732 hasConceptScore W2340377732C71924100 @default.
- W2340377732 hasConceptScore W2340377732C75088862 @default.
- W2340377732 hasConceptScore W2340377732C94915269 @default.
- W2340377732 hasIssue "5" @default.
- W2340377732 hasLocation W23403777321 @default.
- W2340377732 hasLocation W23403777322 @default.
- W2340377732 hasLocation W23403777323 @default.
- W2340377732 hasOpenAccess W2340377732 @default.