Evidence map›Paper›PMID 34612567›Full record

ArticleJournal of applied clinical medical physics2021

First clinical experience of correcting phantom-based image distortion related to gantry position on a 0.35T MR-Linac.

Benjamin C Lewis, Jaeik Shin, Benjamin Quinn, Enzo Barberi, Domenic Sievert, Jin Sung Kim, Taeho Kim

Open access · goldAbstract read
In one paragraph

Article in Journal of applied clinical medical physics, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
1.9field-weighted citation impact, top 14% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

2 citing papers in PubMed, 7 citations in OpenAlex.

  1. Article
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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

7 authors at 3 institutions in 3 countries.

Benjamin C LewisDepartment of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri, USA.
Jaeik ShinDepartment of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri, USA.
Benjamin QuinnDepartment for the Modus Medical, Modus Medical Devices Inc., London, Ontario, Canada.
Enzo BarberiDepartment for the Modus Medical, Modus Medical Devices Inc., London, Ontario, Canada.
Domenic SievertDepartment of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri, USA.
Jin Sung KimDepartment of Radiation Oncology, Yonsei University College of Medicine, Seoul, Republic of Korea.
Taeho KimDepartment of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri, USA.
Washington University in St. Louis · USMarch of Dimes Canada · CAYonsei University · KR

Funding

Korean Government (MSIT) 2020R1A4A101661911
6 · The paper itself

Abstract

MR-guided radiotherapy requires strong imaging spatial integrity to deliver high quality plans and provide accurate dose calculation. The MRI system, however, can be compromised by the integrated linear accelerator (Linac), resulting in inaccurate imaging isocenter position and geometric distortion. Dependence on gantry position further complicates the correction of distortions. This work presents a new clinical application of a commercial phantom and software system that quantifies isocenter alignment and geometric distortion, as well as providing a deformation vector field (DVF). A large distortion phantom and a smaller grid phantom were imaged at multiple gantry angles from 0 to 330° on a 0.35 T integrated MR-Linac. The software package was used to assess geometric distortion and generate DVFs to correct distortions within the phantom volume. The DVFs were applied to the grid phantom with resampling software then evaluated using structural similarity index measure (SSIM). Scans were also performed with a ferromagnetic clip near the phantom to investigate the correction of more severe artifacts. The mean magnitude isocenter shift was 0.67 mm, ranging from 0.25 to 1.04 mm across all angles. The DVF had a mean component value of 0.27 ± 0.02, 0.24 ± 0.01, and 0.19 ± 0.01 mm in the right-left (RL), anterior-posterior (AP), and superior-inferior (SI) directions. The ferromagnetic clip increased isocenter position error from 1.98 mm to 2.20 mm and increased mean DVF component values in the RL and AP directions. The resampled grid phantom had an increased SSIM for all gantry angles compared to original images, increasing from 0.26 ± 0.001 to 0.70 ± 0.004. Through this clinical assessment, we were able to correct geometric distortion and isocenter shift related to gantry position on a 0.35 T MR-Linac using the distortion phantom and software package. This provides encouragement that it could be used for quality assurance and clinically to correct systematic distortion caused by imaging at different gantry angles.

Indexed as

Magnetic Resonance ImagingParticle AcceleratorsHumansPhantoms, ImagingRadionuclide ImagingSoftwaredistortion correctionMRgRTMR-Linac

Identifiers

PMID34612567
PMCPMC8598146
OpenAlexW3204713471

What OpenQuestion holds

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LicenceCC BY
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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.