Evidence map›Paper›PMID 41458175›Full record

ArticleAdvances in radiation oncology2026

Is Ultrahigh Dose Rate Critical for the Effectiveness of Microbeam Radiation Therapy in a Broad-Beam Combined Treatment?

Elette Engels, Helen B Forrester, Verdiana Trappetti, Kellie Mouchemore, Mitzi Klein, Alice H Sprung, Kirsty Brunt, Micah J Barnes, Matthew Cameron, Vincent de Rover and 6 more

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In one paragraph

Article in Advances in radiation oncology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing 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

1 citing paper in PubMed.

  1. Article
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

16 authors.

Elette EngelsCentre of Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, New South Wales, Australia.
Helen B ForresterCentre of Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, New South Wales, Australia.
Verdiana TrappettiInstitute of Anatomy, University of Bern, Bern, Switzerland.
Kellie MouchemoreOlivia Newton John Cancer Research Institute (ONJCRI), Heidelberg, Victoria, Australia.
Mitzi KleinAustralian Synchrotron, Australian Nuclear Science and Technology Organisation (ANSTO), Clayton, Victoria, Australia.
Alice H SprungSchool of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia.
Kirsty BruntAustralian Synchrotron, Australian Nuclear Science and Technology Organisation (ANSTO), Clayton, Victoria, Australia.
Micah J BarnesCentre of Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, New South Wales, Australia.
Matthew CameronAustralian Synchrotron, Australian Nuclear Science and Technology Organisation (ANSTO), Clayton, Victoria, Australia.
Vincent de RoverCentre of Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, New South Wales, Australia.
Bettina de Breuyn DietlerInstitute of Anatomy, University of Bern, Bern, Switzerland.
Anatoly B RosenfeldCentre of Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, New South Wales, Australia.
Michael L F LerchCentre of Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, New South Wales, Australia.
Robin L AndersonOlivia Newton John Cancer Research Institute (ONJCRI), Heidelberg, Victoria, Australia.
Olga A MartinCentre of Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, New South Wales, Australia.
Valentin G DjonovInstitute of Anatomy, University of Bern, Bern, Switzerland.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Purpose: The superior therapeutic index of preclinical synchrotron microbeam radiation therapy (MRT) over conventional broad-beam (BB) radiation therapy (RT) has been clearly established. Published data demonstrate that a combination of 1 MRT session with 2 consecutive daily BB-RT sessions effectively controls the primary tumor and triggers an antitumor immune response. Here, we aimed to establish whether an ultrahigh dose rate of MRT, available exclusively on the synchrotron, is essential for effective treatment of murine triple-negative mammary carcinoma. Methods and Materials: The in vitro response of mammary tumor cells was investigated using a clonogenic survival assay at different MRT dose rates (∼1000, 100, or 10 Gy/s). The in vivo tumor responses at the same dose rates, with an MRT/BB/BB treatment schedule, were evaluated by measuring tumor volume and the induced immune response. Animal survival and normal skin reactions were also assessed. Results: Clonogenic survival decreased with decreasing MRT dose rate, with most cell sparing at the highest dose rate (1000 Gy/s), indicating that lower dose rates could be more effective against tumors. However, no significant differences in in vivo tumor growth delay were observed in response to dose-rate variations. Decreased infiltration of irradiated tumors with leucocytes and their subpopulations was observed at the lower dose rates, including decreased expression of immune checkpoints PD-1/PD-L1 and prognostic marker CD103, which could impact the overall tumor response in vivo. The higher dose rates were associated with increased antitumor immunity. Early euthanasia of mice, as dictated by ethical endpoints, prevented long-term observation of differences in animal survival. Skin toxicity in the vicinity of irradiated tumors was mild and developed later at the highest MRT dose rate. Overall, MRT at 10 to 1000 Gy/s was tolerated similarly, despite dramatic changes in the dose rate. Conclusions: These findings are promising for the clinical translation of MRT in combination with conventional RT, using emerging compact x-ray MRT sources with dose rates lower than those delivered by synchrotron sources.

Identifiers

PMID41458175
PMCPMC12741283

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