ESTRO 2025 - Abstract Book

S3061

Physics - Image acquisition and processing

ESTRO 2025

Conclusion: HS CBCT has been shown previously to have superior imaging quality over TB CBCT (1) which we show translates into meaningful improved confidence with image matching. Despite studies showing comparable imaging quality of HS CBCT to FBCT (2), such as HU accuracy, we show an inferiority in clinicians’ confidence in contouring selected structures, indicating a need for further improvements in CBCT image quality.

Keywords: CBCT image quality

References: 1 - Kunnen B, et. al. The added value of a new high-performance ring-gantry CBCT imaging system for prostate cancer patients. Radiother Oncol. 2024 Nov;200:110458. doi: 10.1016/j.radonc.2024.110458. Epub 2024 Jul 26. PMID: 39069089. 2 - Robar JL et. al. Novel Technology Allowing Cone Beam Computed Tomography in 6 Seconds: A Patient Study of Comparative Image Quality. Pract Radiat Oncol. 2024 May-Jun;14(3):277-286. doi: 10.1016/j.prro.2023.10.014. Epub 2023 Nov 7. PMID: 37939844.

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Poster Discussion Experimental proton and helium pencil beam radiographs with clinical scanner prototype for range guidance in ion therapy Alexander Pryanichnikov 1,2 , Jennifer Hardt 3,4,5 , Lukas Martin 1,4 , Christina Stengl 3,6 , Ethan DeJongh 7 , Fritz DeJongh 7 , Stephan Brons 8 , Oliver Jäkel 3,6,8 , Niklas Wahl 3,5 , Joao Seco 1,4 1 Division of Biomedical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany. 2 Institute of Biomedical Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany. 3 Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany. 4 Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany. 5 Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany. 6 Medical Faculty of Heidelberg, Heidelberg University, Heidelberg, Germany. 7 Research and Development, ProtonVDA LLC, Naperville, USA. 8 Heidelberg Ion-Beam Therapy Centre (HIT), Heidelberg University Hospital, Heidelberg, Germany Purpose/Objective: The HELIOS (HELium Imaging Oncology Scanner) project aims to enhance the precision of ion therapy for lung and abdominal cancers by developing helium radiography using existing proton imaging technologies [1] adapted for mixed helium-carbon beams [2]. As part of this initiative, a prototype clinical proton radiography system was installed at the Heidelberg Ion-Beam Therapy Center (HIT). The primary objectives of this initial phase were twofold: (1) to adapt the prototype to proton and helium beams at HIT; (2) to evaluate the feasibility of single-event proton and helium radiography with single-plane position tracking. Material/Methods: The low-intensity extraction mode of the HIT synchrotron was employed to deliver proton and helium beams, which were used for imaging with the ProtonVDA scanner [1]. A variety of phantoms were utilized for data acquisition, including simple PMMA phantoms, 3D-printed plastic phantoms with line and holes to evaluate spatial resolution, a custom motion phantom to assess the motion reconstruction capabilities, and a calibration cylindrical PMMA phantom with nine tissue-equivalent inserts to evaluate the water-equivalent thickness (WET) reconstruction precision. Moreover, a motorized anthropomorphic abdominal phantom [3] was employed to assess all the mentioned above imaging characteristics in close to real patient geometry (Figure 1).