FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W2955476465> ?p ?o ?g. }

• W2955476465 endingPage "47" @default.
• W2955476465 startingPage "47" @default.
• W2955476465 abstract "47 Objectives: The introduction of time-of-flight (TOF) in medical imaging such as in positron emission tomography (PET) or diffuse optical tomography lead to improvements on image quality. In computed tomography (CT), the signal-to-noise ratio (SNR) can be improved when photon counting along with energy measurements is used. The aim of this study is a) to assess the feasibility of using TOF in CT to discriminate between ballistic and scattered photons based on their travel path in order to reduce the effect of scatter noise and b) identify detector requirements for a first prototype development and to assess if this new approach could be implemented along with TOF-PET in a bimodality scanner using only one detector system. Methods: Herein, a complete flat panel cone-beam scanner is simulated using Geant4 Application for Tomographic Emission (GATE). The simulated scanner comprises a monochromatic X-ray source, irradiating with a cone angle of 16°, plexiglass phantoms of 50, 100, 150 and 200 mm thickness used to generate increasing levels of scatter radiation and a flat panel made of a 256 x 256 array of 1 x 1 x 1 mm3 detectors. A digital scatter rejection algorithm (DSR) compares the TOF of each individual photon with the expected TOF for a direct trajectory and removes the photons who failed to arrive in time. The DSR performance is evaluated first with single projection acquisitions for different configurations, then a full 360° acquisition of a water cylinder with two cylindrical bone inserts is realised to measure the effect of DSR on image quality. In this case, a perfect time resolution is used and 100 keV photons are emitted in a 28° cone towards the detection system comprising a 256 x 256 array of 2 x 2 mm2 pixels. The image was reconstructed using the implementation of the algorithm of Feldkamp, David and Kress (FDK) from the Reconstruction Toolkit (RTK). The experimental setup comprises a pulsed X-ray source N5084 from Hamamatsu and a 3 x 3 mm2Silicon Photomultiplier with a 200 µm thick LYSO:Ce crystal. Two acquisitions, with and without a beam-blocker used to force scattering of photons on the X-ray enclosure, were made to highlight statistical differences between the TOF of ballistic and scattered photons. Results: After traveling through 200 mm of plexiglass, 85% and 40% of all scattered radiation arrives at least 100 and 500 ps later than expected with a median TOF difference of 400 ps. This value decreases to 82 ps with a 50 mm phantom. With photon energies lower than 60 keV and scanner diameter smaller than 500 mm, the time window shrinks and a total time resolution of 10 ps or less is needed to correctly identify almost all primary and scattered photons since these parameters decrease the mean scattering angle and travel path. In a TOF-CT model with perfect time resolution and 120 keV photons, the scatter-to-primary ratio (SPR) can be reduced to less than 3%, even with an initial SPR as high as 300%. With 10 and 100 ps FWHM total resolution, SPR is reduced from 225% to respectively 8% and 40%. In the reconstructed 360° acquisition (Figure 1), when applying the DSR algorithm the SPR decreases from 300% to 4%, the CNR doubles and the cup artifacts are greatly reduced. When applying the DSR a similar CNR to the uncorrected image could be obtained with a 4 fold dose reduction. The experimental setup shows a shift between the TOF of scattered photons and ballistic photons of 389 ps, fitting the expected time for photons to circle the beam-blocker by scattering on the X-ray enclosure. Conclusions: Our results confirms the possibility in both simulation and experiment to measure statistical differences between scattered and ballistic photons. Reducing the time resolution to 10 ps is required in order to almost completely remove the effect of scatter noise, which fits with the goals for TOF-PET. This improvement could lead to a reduction of dose such as in our simulated setup where a 75% dose is observed. As the timing requirements are similar, TOF-CT could be implemented using the same detection system as TOF-PET." @default.
• W2955476465 created "2019-07-12" @default.
• W2955476465 creator A5007578990 @default.
• W2955476465 creator A5013352787 @default.
• W2955476465 creator A5014616032 @default.
• W2955476465 creator A5024872011 @default.
• W2955476465 creator A5073467851 @default.
• W2955476465 creator A5088799983 @default.
• W2955476465 creator A5090319147 @default.
• W2955476465 date "2019-05-01" @default.
• W2955476465 modified "2023-09-23" @default.
• W2955476465 title "Time-of-Flight Computed Tomography a Proof of Principle Study" @default.
• W2955476465 hasPublicationYear "2019" @default.
• W2955476465 type Work @default.
• W2955476465 sameAs 2955476465 @default.
• W2955476465 citedByCount "0" @default.
• W2955476465 crossrefType "journal-article" @default.
• W2955476465 hasAuthorship W2955476465A5007578990 @default.
• W2955476465 hasAuthorship W2955476465A5013352787 @default.
• W2955476465 hasAuthorship W2955476465A5014616032 @default.
• W2955476465 hasAuthorship W2955476465A5024872011 @default.
• W2955476465 hasAuthorship W2955476465A5073467851 @default.
• W2955476465 hasAuthorship W2955476465A5088799983 @default.
• W2955476465 hasAuthorship W2955476465A5090319147 @default.
• W2955476465 hasConcept C115961682 @default.
• W2955476465 hasConcept C120665830 @default.
• W2955476465 hasConcept C121332964 @default.
• W2955476465 hasConcept C127077266 @default.
• W2955476465 hasConcept C159317903 @default.
• W2955476465 hasConcept C163716698 @default.
• W2955476465 hasConcept C2775842073 @default.
• W2955476465 hasConcept C2779751349 @default.
• W2955476465 hasConcept C2989005 @default.
• W2955476465 hasConcept C31972630 @default.
• W2955476465 hasConcept C41008148 @default.
• W2955476465 hasConcept C55020928 @default.
• W2955476465 hasConcept C71924100 @default.
• W2955476465 hasConcept C94898600 @default.
• W2955476465 hasConcept C94915269 @default.
• W2955476465 hasConcept C98960154 @default.
• W2955476465 hasConceptScore W2955476465C115961682 @default.
• W2955476465 hasConceptScore W2955476465C120665830 @default.
• W2955476465 hasConceptScore W2955476465C121332964 @default.
• W2955476465 hasConceptScore W2955476465C127077266 @default.
• W2955476465 hasConceptScore W2955476465C159317903 @default.
• W2955476465 hasConceptScore W2955476465C163716698 @default.
• W2955476465 hasConceptScore W2955476465C2775842073 @default.
• W2955476465 hasConceptScore W2955476465C2779751349 @default.
• W2955476465 hasConceptScore W2955476465C2989005 @default.
• W2955476465 hasConceptScore W2955476465C31972630 @default.
• W2955476465 hasConceptScore W2955476465C41008148 @default.
• W2955476465 hasConceptScore W2955476465C55020928 @default.
• W2955476465 hasConceptScore W2955476465C71924100 @default.
• W2955476465 hasConceptScore W2955476465C94898600 @default.
• W2955476465 hasConceptScore W2955476465C94915269 @default.
• W2955476465 hasConceptScore W2955476465C98960154 @default.
• W2955476465 hasOpenAccess W2955476465 @default.
• W2955476465 hasRelatedWork W119105369 @default.
• W2955476465 hasRelatedWork W1983196237 @default.
• W2955476465 hasRelatedWork W1990243010 @default.
• W2955476465 hasRelatedWork W2007809863 @default.
• W2955476465 hasRelatedWork W2014760116 @default.
• W2955476465 hasRelatedWork W2050279949 @default.
• W2955476465 hasRelatedWork W2054738744 @default.
• W2955476465 hasRelatedWork W2074430327 @default.
• W2955476465 hasRelatedWork W2075734152 @default.
• W2955476465 hasRelatedWork W2086305836 @default.
• W2955476465 hasRelatedWork W2097389888 @default.
• W2955476465 hasRelatedWork W2129409738 @default.
• W2955476465 hasRelatedWork W2536883988 @default.
• W2955476465 hasRelatedWork W2594367499 @default.
• W2955476465 hasRelatedWork W2922054235 @default.
• W2955476465 hasRelatedWork W2922166939 @default.
• W2955476465 hasRelatedWork W3043676508 @default.
• W2955476465 hasRelatedWork W3055822614 @default.
• W2955476465 hasRelatedWork W3195230218 @default.
• W2955476465 hasRelatedWork W3214479709 @default.
• W2955476465 hasVolume "60" @default.
• W2955476465 isParatext "false" @default.
• W2955476465 isRetracted "false" @default.
• W2955476465 magId "2955476465" @default.
• W2955476465 workType "article" @default.