MRI and FUNDUS image fusion for improved ocular biometry in Ocular Proton Therapy. (September 2022)

• Record Type: Journal Article
• Authors: Via, Riccardo; Pica, Alessia; Antonioli, Luca; Paganelli, Chiara; Fattori, Giovanni; Spaccapaniccia, Chiara; Lomax, Antony; Weber, Damien Charles; Schalenbourg, Ann; Baroni, Guido; Hrbacek, Jan
• Is Part Of: Radiotherapy and oncology. Volume 174(2022)
• Page Start: 16
• Page End: 22
• Publication Date: 2022-09
• Subjects: Ocular Proton Therapy -- Magnetic resonance imaging -- Panoramic Fundus Photography -- Multi-modality Image Fusion -- Target Volume Definition; Oncology -- Periodicals; Radiotherapy -- Periodicals; Tumors -- Periodicals; Medical Oncology -- Periodicals; Neoplasms -- radiotherapy -- Periodicals; Radiotherapy -- Periodicals; Radiothérapie -- Périodiques; Cancérologie -- Périodiques; Tumeurs -- Périodiques; Electronic journals; 616.9940642
• DOI: 10.1016/j.radonc.2022.06.021
• Languages: English
• ISSNs: 0167-8140

Abstract

Highlights: A multi-modality imaging approach for ocular biometry in Proton Therapy is presented. The chosen ophthalmological imaging modality were MRI and panoramic fundus photography . Eighteen uveal melanoma patients were included in this comparative analysis. Image fusion allows to identify of the shallowest parts of the tumour. A significant improvement in the personalisation of the eye model is achieved. Abstract: Introduction: Ocular biometry in Ocular Proton Therapy (OPT) currently relies on a generic geometrical eye model built by referencing surgically implanted markers. An alternative approach based on image fusion of volumetric Magnetic Resonance Imaging (MRI) and panoramic fundus photography was investigated. Materials and methods: Eighteen non-consecutive uveal melanoma (UM) patients, who consented for an MRI and had their tumour base visible on panoramic fundus photography, were included in this comparative analysis. Through generating digitally-reconstructed projections from MRI images using the Lambert azimuthal equal-area projection, 2D-3D image fusion between fundus photography and an eye model delineated on MRI scans was achieved and allowed for a novel definition of the target base (MRI + FCTV ). MRI + FCTV was compared with MRI-only delineation (MRIGTV ) and the conventional (EyePlan) target definition (EPCTV ). Results: The combined use of fundus photography and MRI to define tumour volumes reduced the average discrepancies by almost 65% with respect to the MRI only tumour definitions when comparing with the conventionally planned EPCTV . With the proposed method, shallow sub-retinal tumour infiltration, otherwise invisible on MRI, can be included in the target volume definition. Moreover, a novel definition of the fovea location improves the accuracy and personalisation of the 3D eye model. Conclusion: MRI and fundus image fusion overcomes some of the limitations of ophthalmological MRI for tumour volume definition in OPT. This novel eye tumour modelling method might improve treatment planning personalisation, allowing to better anticipate which patients could benefit from prophylactic treatment protocols for radiation induced maculopathy.