Evidence map›Paper›PMID 39475282›Full record

ArticleMedical physics2025

Monte Carlo modeling of the origin of contaminant electrons on a 0.5T bi-planar Linac-MR.

Michael Reynolds, Patricia A K Oliver, Tania Wood, Eugene Yip, Shima Y Tari, Keith Wachowicz, Ben Burke, B Gino Fallone

Abstract read
In one paragraph

Article in Medical physics, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 3 papers.

0numbers the graph read from it
0cells of the map it votes in
3citing papers in PubMed
–field-weighted citation impact
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

3 citing papers in PubMed.

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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

8 authors.

Michael ReynoldsDepartment of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada.
Patricia A K OliverUniversity of Alberta, Department of Oncology, Division of Medical Physics, Edmonton, Alberta, Canada.
Tania WoodDepartment of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada.
Eugene YipDepartment of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada.
Shima Y TariDepartment of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada.
Keith WachowiczDepartment of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada.
Ben BurkeDepartment of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada.
B Gino FalloneDepartment of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

introductionIn the last decade, hybrid linear accelerator magnetic resonance imaging (Linac-MR) devices have evolved into FDA-cleared clinical tools, facilitating magnetic resonance guided radiotherapy (MRgRT). The addition of a magnetic field to radiation therapy has previously demonstrated dosimetric and electron effects regardless of magnetic field orientation. PURPOSE: This study uses Monte Carlo simulations to investigate the importance and efficacy of the magnetic field design in mitigating surface dose enhancement in the Aurora-RT, focusing specifically on contaminant electrons, their origin, and energy spectrum.

methodsThe Aurora-RT 0.5 T Biplanar Linac-MR device was modeled using the BEAMnrc package using the updated EM macros, a magnetic field map generated from Opera 3D. Simulation generated phasespace data at the distal side of the first magnetic pole plate (89 cm) and at machine isocenter (120 cm) were analyzed with respect to electron energy spectra and electron creation origins, both with and without the static magnetic field.

resultsThe presence of the main magnetic field was verified to affect the origin and distribution of contaminant electrons, removing them from the air column up to 60 cm from the target, and focusing them along the CAX within the region below. Analysis of the remaining electron energy fluence reveals the net removal of electrons with energies > 2 MeV and generation of electrons with energies < 2 MeV in the presence of the static magnetic field as compared to no magnetic field. Moreover, in the presence of the magnetic field the integral energy contained in the contaminant electrons increases from 89 cm to isocenter but is still 15% less overall than the integral energy contained in contaminant electrons without the magnetic field.

conclusionThis study provides an analysis of contaminant electrons in the Aurora-RT 0.5 T Linac-MR, emphasizing the role of magnetic field design in successfully minimizing electron contaminants.

Indexed as

ElectronsMagnetic Resonance ImagingMonte Carlo MethodParticle AcceleratorsMagnetic FieldsRadiotherapy, Image-Guidedelectron contaminationMR‐Linacsurface dose

Identifiers

PMID39475282
PMCPMC11788252

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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.