ESTRO 2024 - Abstract Book

S3852

Physics - Image acquisition and processing

ESTRO 2024

GTV delineations based only on anatomical MR imaging tend to overestimate the tumor volume. The availability of DW-SPLICE MRI leads to a smaller delineated volume with an increased PPV while maintaining adequate tumor coverage (sensitivity). However, the inter-observer delineation variability did not improve when DW-SPLICE MRI was available.

Keywords: GTV validation, Diffusion weighted imaging

References:

1. Schakel T, Hoogduin JM, Terhaard CHJ, Philippens MEP. Technical Note: Diffusion-weighted MRI with minimal distortion in head-and-neck radiotherapy using a turbo spin echo acquisition method: Diffusion-weighted. Med Phys. 2017;44(8):4188-4193. doi:10.1002/mp.12363

2. Caldas-Magalhaes J, Kasperts N, Kooij N, et al. Validation of imaging with pathology in laryngeal cancer: Accuracy of the registration methodology. Int J Radiat Oncol Biol Phys. 2012;82(2). doi:10.1016/j.ijrobp.2011.05.004

3. Kouwenhoven E, Giezen M, Struikmans H. Measuring the similarity of target volume delineations independent of the number of observers. Phys Med Biol. 2009;54(9):2863-2873. doi:10.1088/0031-9155/54/9/018

1617

Proffered Paper

A comparison of carbon ions versus protons for integrated mode ion imaging

Mikaël Simard 1 , Ryan Fullarton 1 , Lennart Volz 2 , Christoph Schuy 2 , Daniel Robertson 3 , Allison Toltz 4 , Colin Baker 4 , Sam Beddar 5 , Christian Graeff 2 , Charles-Antoine Collins-Fekete 1 1 University College London, Medical Physics and Biomedical Engineering, London, United Kingdom. 2 GSI Helmholtz Centre for Heavy Ion Research GmbH, Biophysics, Darmstadt, Germany. 3 Mayo Clinic Arizona, Division of Medical Physics, Department of Radiation Oncology, Phoenix, USA. 4 University College London Hospital, Department of Radiotherapy Physics, London, United Kingdom. 5 The University of Texas MD Anderson Cancer Center, Department of Radiation Physics, Houston, USA

Purpose/Objective:

Ion beam therapy presents many advantages over conventional radiotherapy. However, uncertainties in beam range estimation can hinder the capacity of delivering the planned dose distribution, limiting the potential of ion beam therapy. Using the treatment source to capture transmission ion radiographs (iRads) is a promising avenue to limit uncertainties in ion beam therapy. For instance, ion radiographs could be used for indirect in-vivo range verification, and low-dose image guidance at the treatment site [1]. The latter may include online adaptive radiotherapy for cancers such as non-small cell lung cancer [2]. For establishing the potential benefits of ion image guidance, it is critical to evaluate the image quality of ion radiography systems.