A commissioning protocol for portal imaging-based radiotherapy in vivo dosimetry systems
Esposito, M. (S.O.C. Fisica Sanitaria- Azienda Sanitaria USL Toscana Centro)
Baldoni, R. (U.OC-Fisica Medica e alte tecnologie. AST Pesaro Urbino)
Bossuyt, E. (Iridium Netwerk)
Bresciani, S. (Candiolo Cancer Institute-FPO IRCCS)
Clark, C.H (National Physical Laboratory (Londres, Regne Unit))
Jones, M. (Royal Surrey NHS Foundation Trust)
Kry, S. (The University of Texas M.D. Anderson Cancer Center)
Perry, J. (Royal Surrey NHS Foundation Trust)
van de Kamer, J. (The Netherlands Cancer Institute (NKI) (Netherlands))
Verellen, Dirk (Antwerp University)
Jornet, Nuria (Institut de Recerca Sant Pau)
Universitat Autònoma de Barcelona

Date:	2024
Abstract:	Background and Purpose: With the availability of commercial electronic portal imaging detector-based in vivo dosimetry (EPID-based IVD) solutions, many radiotherapy departments are adopting this technology. However, comprehensive commissioning guidance is lacking. This study aims to provide a protocol for testing the accuracy and sensitivity of EPID-based IVD systems. Material and methods: The protocol was tested across four institutions using two different systems. Accuracy was evaluated with homogeneous slab phantoms using different square regular fields, and clinical plans in a CIRS lung phantom. Multiple forward and back-projected algorithm implementations were assessed for different energies. Sensitivity analysis in the lung phantom examined responses to setup errors, anatomical variations, and delivery errors. Results: In homogeneous phantoms, over 85 % of pixels passed the 5 %/2mm gamma criteria, except for the 2x2 cm field. In the lung phantom, all systems and implementations achieved over 95 %-pixel pass rates at the 2 %/2mm criterion for volumetric modulated arc therapy (VMAT) plans. For conformal radiation therapy (3DCRT) plans, one system implementation showed poor accuracy, with over 90 % agreement only at the 5 %/2mm criterion. Considering all systems and implementations, average sensitivity and specificity for CRT plans ranged from 0. 92 and 0. 42 (at 2 %/2mm) to 0. 71 and 0. 52 (at 5 %/2mm), while for VMAT plans ranged from 0. 41 and 0. 81 (at 2 %2mm) to 0. 37 and 0. 81 (at 5 %/2mm). Conclusion: We successfully developed a protocol to commission EPID IDV systems. It was found that not all systems and implementations achieved satisfactory accuracy and sensitivity, emphasising the need for thorough commissioning and benchmarking.
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Dosimetry ; EPID ; QA ; "In vivo" dose measurements
Published in:	Physics and Imaging in Radiation Oncology, Vol. 32 (october 2024) , p. 100666, ISSN 2405-6316

DOI: 10.1016/j.phro.2024.100666
PMID: 39624392

8 p, 1.4 MB

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Articles > Research articles
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