English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

MRI offers outstanding soft tissue contrast that may reduce uncertainties intarget and organ-at-risk delineation and enable online adaptive image-guidedtreatment. Spatial distortions resulting from non-linearities in the gradientfields and non-uniformity in the main magnetic field must be accounted foracross the imaging field-of-view to prevent systematic errors during treatmentdelivery. This work presents a modular phantom and software application tocharacterize geometric distortion (GD) within the large field-of-view MRIimages required for radiation therapy simulation. The modular phantom isassembled from a series of rectangular foam blocks containing high-contrastfiducial markers in a known configuration. The modular phantom designfacilitates transportation of the phantom between different MR scanners andMR-guided linear accelerators and allows the phantom to be adapted to fitdifferent sized bores or coils. The phantom was evaluated using a 1.5TMR-guided linear accelerator (MR-Linac) and 1.5T and 3.0T diagnostic scanners.Performance was assessed by varying acquisition parameters to induce imagedistortions in a known manner. Imaging was performed using T1 and T2 weightedpulse sequences with 2D and 3D distortion correction algorithms and thereceiver bandwidth (BW) varied as 250-815 Hz/pixel. Phantom set-upreproducibility was evaluated across independent set-ups. The software wasvalidated by comparison with a non-modular phantom. Average geometricdistortion was 0.94+/-0.58 mm for the MR-Linac, 0.90+/-0.53 mm for the 1.5 Tscanner, and 1.15+/-0.62 mm for the 3.0T scanner, for a 400 mm diametervolume-of-interest. GD increased, as expected, with decreasing BW, and with the2D versus 3D correction algorithm. Differences in GD attributed to phantomset-up were 0.13 mm or less. Differences in GD for the two softwareapplications were less than 0.07 mm.

A modular phantom and software to characterize 3D geometric distortion in MRI