Evidence map›Paper›PMID 35870154›Full record

ArticleMedical physics2022

Generation of synthetic megavoltage CT for MRI-only radiotherapy treatment planning using a 3D deep convolutional neural network.

Jessica E Scholey, Abhejit Rajagopal, Elena Grace Vasquez, Atchar Sudhyadhom, Peder Eric Zufall Larson

Abstract read
In one paragraph

Article in Medical physics, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 8 papers, 2 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
8citing papers in PubMed, 2 pooled it
–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

8 citing papers in PubMed, 2 syntheses or guidelines pooled it.

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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

5 authors.

Jessica E ScholeyDepartment of Radiation Oncology, The University of California, San Francisco, San Francisco, California, USA.
Abhejit RajagopalDepartment of Radiology and Biomedical Imaging, The University of California, San Francisco, San Francisco, California, USA.
Elena Grace VasquezDepartment of Physics, The University of California, Berkeley, Berkeley, California, USA.
Atchar SudhyadhomDepartment of Radiation Oncology, Brigham & Women's Hospital/Dana-Farber Cancer Institute/Harvard Medical School, Boston, Massachusetts, USA.
Peder Eric Zufall LarsonDepartment of Radiology and Biomedical Imaging, The University of California, San Francisco, San Francisco, California, USA.

Funding

A Multimodal Imaging Approach Towards the Reduction of Proton Beam Range UncertaintiesR21EB026086 · NIBIB · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · PI SUDHYADHOM, ATCHAR · 2018 to 2020
$594k
NIBIB NIH HHS R21 EB026086NIBIB of the National Institutes of Health R21EB026086
6 · The paper itself

Abstract

backgroundMegavoltage computed tomography (MVCT) has been implemented on many radiotherapy treatment machines for on-board anatomical visualization, localization, and adaptive dose calculation. Implementing an MR-only workflow by synthesizing MVCT from magnetic resonance imaging (MRI) would offer numerous advantages for treatment planning and online adaptation. PURPOSE: In this work, we sought to synthesize MVCT (sMVCT) datasets from MRI using deep learning to demonstrate the feasibility of MRI-MVCT only treatment planning.

methodsMVCTs and T1-weighted MRIs for 120 patients treated for head-and-neck cancer were retrospectively acquired and co-registered. A deep neural network based on a fully-convolutional 3D U-Net architecture was implemented to map MRI intensity to MVCT HU. Input to the model were volumetric patches generated from paired MRI and MVCT datasets. The U-Net was initialized with random parameters and trained on a mean absolute error (MAE) objective function. Model accuracy was evaluated on 18 withheld test exams. sMVCTs were compared to respective MVCTs. Intensity-modulated volumetric radiotherapy (IMRT) plans were generated on MVCTs of four different disease sites and compared to plans calculated onto corresponding sMVCTs using the gamma metric and dose-volume-histograms (DVHs).

resultsMAE values between sMVCT and MVCT datasets were 93.3 ± 27.5, 78.2 ± 27.5, and 138.0 ± 43.4 HU for whole body, soft tissue, and bone volumes, respectively. Overall, there was good agreement between sMVCT and MVCT, with bone and air posing the greatest challenges. The retrospective dataset introduced additional deviations due to sinus filling or tumor growth/shrinkage between scans, differences in external contours due to variability in patient positioning, or when immobilization devices were absent from diagnostic MRIs. Dose distributions of IMRT plans evaluated for four test cases showed close agreement between sMVCT and MVCT images when evaluated using DVHs and gamma dose metrics, which averaged to 98.9 ± 1.0% and 96.8 ± 2.6% analyzed at 3%/3 mm and 2%/2 mm, respectively.

conclusionsMVCT datasets can be generated from T1-weighted MRI using a 3D deep convolutional neural network with dose calculation on a sample sMVCT in close agreement with the MVCT. These results demonstrate the feasibility of using MRI-derived sMVCT in an MR-only treatment planning workflow.

Indexed as

Radiotherapy Planning, Computer-AssistedTomography, X-Ray ComputedHumansMagnetic Resonance ImagingNeural Networks, ComputerRadiotherapy DosageRetrospective Studiesdose calculation for radiotherapymagnetic resonance imagingquantitative imaging

Identifiers

PMID35870154
PMCPMC9588542

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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.