Varian TrueBeam Auto Beam Hold

Varian’s Advanced IGRT & Motion package includes the Auto Beam Hold (ABH) feature. ABH is an imaging technique that monitors the patient during radiation treatments. This is achieved by detecting implanted fiducials in radiographic images acquired during treatment. The treatment beam is paused when ABH observes a discrepancy between the planned marker positions and the detected positions. Learn more

A recent study of 132 prostate cancer patients, with Gold Anchor markers automatically detected on TrueBeam, showed that:

  • Across 2659 fractions, intrafraction motion correction was performed 582 times, in 463 fractions (17%);
  • 77% of the patients had at least one shift during their treatment course; the median shift was 3.6 mm; and
  • 36% of the patients had shifts with an average magnitude of at least 5 mm.

– ASTRO 2023 abstract from The University of Chicago Comprehensive Cancer Center

We believe that the combination of Gold Anchor and ABH creates unprecedented opportunities to provide safe and economical radiotherapy with high accuracy and precision.

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“We used the Gold Anchor ducial markers in this feasibility study because these markers were our standard, as they can be deployed with a smaller 22G preloaded needle compared to other markers. The ability to deploy a crumpled marker has also been suggested to improve localization stability due to irregular folding within tissue. […] Periodic kV imaging with automatic detection of motion during VMAT prostate treatments is commercially available, and can be successfully implemented to mitigate effects of intrafraction motion with careful attention to software settings.”
– Article from University of Chicago Medical Center.

“Triggered imaging seems to perform satisfactorily when used in combination with well-separated and compressed Gold Anchor fiducials.”
– Abstract from Sahlgrenska University Hospital, Gothenburg, Sweden.

Gold Anchor markers detected by Truebeam in prostate
Gold Anchor fiducial markers in prostate.

Gold Anchor markers detected by Truebeam in liver
Gold Anchor fiducial markers in liver.

Gold Anchor fiducial markers in prostate, automatically detected by Varian TrueBeam®. Images courtesy of the Sahlgrenska University Hospital.

Note: Varian and Varian Medical Systems are registered trademarks, and TrueBeam® is a trademark of Varian Medical Systems, Inc.

We have used Gold Anchor with TrueBeam triggered images in prostate and liver since the spring of 2019. By implementing automatic marker detection with periodic kV imaging we can now monitor intrafraction motion during radiotherapy. This provides a new level of confidence when adopting more hypofractionated treatments.

Magnus Gustafsson

1st Medical Physicist, Sahlgrenska University Hospital, Gothenburg, Sweden