ESTRO 2024 - Abstract Book

S3768

Physics - Image acquisition and processing

ESTRO 2024

relation was used to map retinal locations to a fundus image, using a simplified camera model consisting of a single aspherical lens.

Conclusion:

The second nodal point proves to be a suitable, patient-specific, reference point to correlate optical fundus images to 3D geometrical data such as MRI, with small, sub-degree errors. This opens the path to accurately incorporate fundus photography in ocular PT planning, as has been proposed by different studies as an essential step to improve its accuracy.

Keywords: uveal melanoma, proton therapy, optical imaging

References:

[1] L. van Vught et al., “ZOSPy: optical ray tracing in Python through OpticStudio”, J. Open Source Softw., 2023.

[2] L. van Vught et al., “MRI-based 3D retinal shape determination,” BMJ Open Ophthalmol., Nov. 2021, doi: 10.1136/bmjophth-2021-000855.

[3] I. K. Daftari et al., “Fundus image fusion in EYEPLAN software: An evaluation of a novel technique for ocular melanoma radiation treatment planning”, Med. Phys., 2010, doi: 10.1118/1.3488891.

[4] A. T. Corcoran, “Ultra-widefield optical coherence tomography of the human retina”, EngD, University of Glasgow, 2015. Accessed: Jun. 01, 2023. [Online]. Available: https://eleanor.lib.gla.ac.uk/record=b3155173

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Digital Poster

A simplistic site-specific approach to fanbeam CBCT HU calibration for RT planning using Elekta XVI.

Dominika I Oborska-Kumaszynska, Julian Liu, Arun Jaganathan, Edis Dedovic, Ching Choi

Nuffield Health Cancer Centre London, Physics, London, United Kingdom

Purpose/Objective:

The aim of this study is to calibrate the Elekta XVI (version R.5.0.6) kilovoltage cone-beam computed tomography (kV CBCT) imaging system in order to introduce a CBCT calibration curve for radiotherapy (RT) treatment (re)planning. This curve essentially provides a way to convert HU to CBCT pixel values into a meaningful way to measure of equivalent dose which is crucial for dose verification.