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Experimental Comparison of Fiducial Markers Used in Proton Therapy: Study of Different Imaging Modalities and Proton Fluence Perturbations Measured With CMOS Pixel Sensors

Reidel, Claire-Anne ; Horst, Felix ; Schuy, Christoph ; Jäkel, Oliver ; Ecker, Swantje ; Henkner, Katrin ; Brons, Stephan ; Durante, Marco ; Weber, Uli (2022):
Experimental Comparison of Fiducial Markers Used in Proton Therapy: Study of Different Imaging Modalities and Proton Fluence Perturbations Measured With CMOS Pixel Sensors. (Publisher's Version)
In: Frontiers in Oncology, 12, Frontiers Media S.A., e-ISSN 2234-943X,
DOI: 10.26083/tuprints-00021125,
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Item Type: Article
Origin: Secondary publication DeepGreen
Status: Publisher's Version
Title: Experimental Comparison of Fiducial Markers Used in Proton Therapy: Study of Different Imaging Modalities and Proton Fluence Perturbations Measured With CMOS Pixel Sensors
Language: English
Abstract:

Fiducial markers are used for image guidance to verify the correct positioning of the target for the case of tumors that can suffer interfractional motion during proton therapy. The markers should be visible on daily imaging, but at the same time, they should produce minimal streak artifacts in the CT scans for treatment planning and induce only slight dose perturbations during particle therapy. In this work, these three criteria were experimentally investigated at the Heidelberg Ion Beam Therapy Center. Several small fiducial markers with different geometries and materials (gold, platinum, and carbon-coated ZrO₂) were evaluated. The streak artifacts on treatment planning CT were measured with and without iMAR correction, showing significantly smaller artifacts from markers lighter than 6 mg and a clear improvement with iMAR correction. Daily imaging as X-ray projections and in-room mobile CT were also performed. Markers heavier than 6 mg showed a better contrast in the X-ray projections, whereas on the images from the in-room mobile CT, all markers were clearly visible. In the other part of this work, fluence perturbations of proton beams were measured for the same markers by using a tracker system of several high spatial resolution CMOS pixel sensors. The measurements were performed for single-energy beams, as well as for a spread-out Bragg peak. Three-dimensional fluence distributions were computed after reconstructing all particle trajectories. These measurements clearly showed that the ZrO₂ markers and the low-mass gold/platinum markers (0.35mm diameter) induce perturbations being 2–3 times lower than the heavier gold or platinum markers of 0.5mm diameter. Monte Carlo simulations, using the FLUKA code, were used to compute dose distributions and showed good agreement with the experimental data after adjusting the phase space of the simulated proton beam compared to the experimental beam.

Journal or Publication Title: Frontiers in Oncology
Volume of the journal: 12
Place of Publication: Darmstadt
Publisher: Frontiers Media S.A.
Collation: 18 Seiten
Uncontrolled Keywords: fiducial marker, dose perturbation, proton therapy, CMOS pixel sensor, image guidance, streak artifacts, Monte Carlo simulation
Classification DDC: 500 Naturwissenschaften und Mathematik > 530 Physik
500 Naturwissenschaften und Mathematik > 570 Biowissenschaften, Biologie
600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin, Gesundheit
Divisions: 05 Department of Physics > Institute for Condensed Matter Physics > Biophysics
Date Deposited: 09 May 2022 13:37
Last Modified: 30 Sep 2022 06:24
DOI: 10.26083/tuprints-00021125
Corresponding Links:
URN: urn:nbn:de:tuda-tuprints-211254
SWORD Depositor: Deep Green
URI: https://tuprints.ulb.tu-darmstadt.de/id/eprint/21125
PPN: 499795679
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