ArticleMedical physics2025
Entry skin dose reduction in an inline MRI-linac using an electron contamination deflector coupled with a helium volume.
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 2 papers.
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.
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.
Who cites it
2 citing papers in PubMed.
- A Review of the Australian MRI Linac Program: From Pie in the Sky to Research Milestone.Journal of medical imaging and radiation oncology · 2026Review
- Entry skin dose reduction in an inline MRI-linac using an electron contamination deflector coupled with a helium volume.Medical physics · 2025Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
6 authors.
Funding
Abstract
backgroundA unique feature of inline MRI-linac prototype systems is the changes to entry surface or skin doses. For the high field (1 T) Australian MRI-linac prototype, a strong surface dose increase is observed. This is a by-product of secondary electron contamination being focused down the MRI bore due to the magnetic field being parallel with the x-ray beam direction. It has been anticipated that future clinical treatments will utilize a 2 cm thick water equivalent bolus layer in air above the patient's skin to absorb the electron contamination that causes the large dose hot spot. However, this will reduce the maximum dose rate of the beam and negate the skin dose-sparing effect typical of MV x-ray beams. PURPOSE: To explore through Monte Carlo (MC) modeling and experimental (Exp) measurements, the skin dose changes when employing a small bespoke permanent magnet electron contamination deflector (ECD) in combination with a helium gas volume (HV) located in the MRI bore. The ECD will purge electron contamination from the beam before it reaches the MRI bore, while the HV minimizes the reintroduction of the contamination above the patient.
methods3D magnetic field models of the Australian MRI-linac coupled with and without the ECD were created in COMSOL Multiphysics, and the magnetic field maps were imported into Geant4 MC simulations. The Geant4 simulations included the 6 MV linac, multileaf collimator (MLC), ECD, HV and a 30
resultsThe skin dose hot spot maximum is measured to be 122.5% (2.4
conclusionsThe inclusion of an ECD coupled with a HV in an inline MRI-linac prototype system has significantly reduced the intensity of the skin dose increases. It appears to be superior solution over a generic 2 cm water bolus for all field sizes and also will retain some skin dose-sparing effect. The methods used in this work are expected to be feasible with other inline MRI-linac designs.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
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.