Evidence map›Paper›PMID 34231963›Full record

ArticleJournal of applied clinical medical physics2021

Clinical assessment of geometric distortion for a 0.35T MR-guided radiotherapy system.

John Neylon, Kiri A Cook, Yingli Yang, Dongsu Du, Ke Sheng, Robert K Chin, Amar U Kishan, James M Lamb, Daniel A Low, Minsong Cao

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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 5 papers.

0numbers the graph read from it
0cells of the map it votes in
5citing papers in PubMed
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1 · What the graph read from it

What it found

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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

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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

5 citing papers in PubMed.

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4 · The record

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5 · Who and what money

Authors and funding

10 authors.

John NeylonDepartment of Radiation Oncology, University of California, Los Angeles (UCLA), Los Angeles, CA, USA.
Kiri A CookDepartment of Radiation Medicine, Oregon Health & Science University, Oregon, Portland, OR, USA.
Yingli YangDepartment of Radiation Oncology, University of California, Los Angeles (UCLA), Los Angeles, CA, USA.
Dongsu DuDepartment of Radiation Oncology, City of Hope Cancer Center, Los Angeles, CA, USA.
Ke ShengDepartment of Radiation Oncology, University of California, Los Angeles (UCLA), Los Angeles, CA, USA.
Robert K ChinDepartment of Radiation Oncology, University of California, Los Angeles (UCLA), Los Angeles, CA, USA.
Amar U KishanDepartment of Radiation Oncology, University of California, Los Angeles (UCLA), Los Angeles, CA, USA.
James M LambDepartment of Radiation Oncology, University of California, Los Angeles (UCLA), Los Angeles, CA, USA.
Daniel A LowDepartment of Radiation Oncology, University of California, Los Angeles (UCLA), Los Angeles, CA, USA.
Minsong CaoDepartment of Radiation Oncology, University of California, Los Angeles (UCLA), Los Angeles, CA, USA.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

purposeTo estimate the overall spatial distortion on clinical patient images for a 0.35 T MR-guided radiotherapy system.

methodsTen patients with head-and-neck cancer underwent CT and MR simulations with identical immobilization. The MR images underwent the standard systematic distortion correction post-processing. The images were rigidly registered and landmark-based analysis was performed by an anatomical expert. Distortion was quantified using Euclidean distance between each landmark pair and tagged by tissue interface: bone-tissue, soft tissue, or air-tissue. For baseline comparisons, an anthropomorphic phantom was imaged and analyzed.

resultsThe average spatial discrepancy between CT and MR landmarks was 1.15 ± 1.14 mm for the phantom and 1.46 ± 1.78 mm for patients. The error histogram peaked at 0-1 mm. 66% of the discrepancies were <2 mm and 51% <1 mm. In the patient data, statistically significant differences (p-values < 0.0001) were found between the different tissue interfaces with averages of 0.88 ± 1.24 mm, 2.01 ± 2.20 mm, and 1.41 ± 1.56 mm for the air/tissue, bone/tissue, and soft tissue, respectively. The distortion generally correlated with the in-plane radial distance from the image center along the longitudinal axis of the MR.

conclusionSpatial distortion remains in the MR images after systematic distortion corrections. Although the average errors were relatively small, large distortions observed at bone/tissue interfaces emphasize the need for quantitative methods for assessing and correcting patient-specific spatial distortions.

Indexed as

Magnetic Resonance ImagingRadiotherapy Planning, Computer-AssistedHumansPhantoms, Imaginggeometric distortionMRgRTMR-guided radiotherapypatient-specific distortion

Identifiers

PMID34231963
PMCPMC8364259

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