Clinical rationale for in vivo portal dosimetry in magnetic resonance guided online adaptive radiotherapy

Maiques, Begoña Vivas; Ruiz, Igor Olaciregui; Janssen, Tomas; Mans, A.

doi:10.1016/j.phro.2022.06.005

Cited by 6 publications

(2 citation statements)

References 33 publications

(39 reference statements)

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“…The possibility of real-time imaging gives the opportunity for intra-fraction adaptations [30] , which opens the door to dose guided optimisation. The delivered dose could be determined using real-time methods to determine the dose, such as Electronic Portal Imaging Device and logfiles [31] , [32] . The delivered dose should be accumulated for these intra-fraction adaptations on changing anatomies, probably using DIR [33] .…”

Section: Discussionmentioning

confidence: 99%

Experimental validation of multi-fraction online adaptations in magnetic resonance guided radiotherapy

van den Dobbelsteen,

Hackett,

van Asselen

et al. 2023

Physics and Imaging in Radiation Oncology

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Section: Discussionmentioning

confidence: 99%

Experimental validation of multi-fraction online adaptations in magnetic resonance guided radiotherapy

van den Dobbelsteen,

Hackett,

van Asselen

et al. 2023

Physics and Imaging in Radiation Oncology

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“…The direction of OTM is to become a clinical tool for adaptive plan decision making. Even for advanced imaging workflows such as the MR-linac, OTM has an argued role which provides assurances in the daily delivered dose (Maiques et al 2022).…”

Section: Rationale For Online Treatment Monitoringmentioning

confidence: 99%

IPEM topical report: guidance for the clinical implementation of online treatment monitoring solutions for IMRT/VMAT

Stevens

Moloney

Blackmore³

et al. 2023

Phys. Med. Biol.

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This report provides guidance for the implementation of online treatment monitoring (OTM) solutions in radiotherapy (RT), with a focus on modulated treatments. Support is provided covering the implementation process, from identification of an OTM solution to local implementation strategy. Guidance has been developed by a RT special interest group (RTSIG) working party (WP) on behalf of the Institute of Physics and Engineering in Medicine (IPEM). Recommendations within the report are derived from the experience of the WP members (in consultation with manufacturers, vendors and user groups), existing guidance or legislation and a UK survey conducted in 2020 (Stevens et al., 2021).OTM is an inclusive term representing any system capable of providing a direct or inferred measurement of the delivered dose to a RT patient. Information on each type of OTM is provided but, commensurate with UK demand, guidance is largely influenced by in vivo dosimetry (IVD) methods utilising the electronic portal imager device (EPID).Sections are included on the choice of OTM solutions, acceptance and commissioning methods with recommendations on routine quality control, analytical methods and tolerance setting, clinical introduction and staffing/resource requirements. The guidance aims to give a practical solution to sensitivity and specificity testing. Functionality is provided for the user to introduce known errors into treatment plans for local testing. Receiver operating characteristic (ROC) analysis is discussed as a tool to performance assess OTM systems. OTM solutions can help verify the correct delivery of radiotherapy treatment. Furthermore, modern systems are increasingly capable of providing clinical decision-making information which can impact the course of a patient’s treatment. However, technical limitations persist. It is not within the scope of this guidance to critique each available solution, but the user is encouraged to carefully consider workflow and engage with manufacturers in resolving compatibility issues. 

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Which failures do patient‐specific quality assurance systems need to catch?

O'Daniel,

Masgrau,

Clark

et al. 2024

Medical Physics

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BackgroundThe Joint AAPM‐ESTRO TG‐360 is developing a quantitative framework to evaluate treatment verification systems used for patient‐specific quality assurance (PSQA). A subgroup was commissioned to determine which potential failure modes had the greatest risk to treatment quality and safety, and therefore should be evaluated as part of the PSQA verification.PurposeTo create an extensive database of potential radiotherapy failure modes that should be detected by PSQA and to determine their relative importance for maximizing treatment quality.MethodsThe subgroup consisted of eight physicists from seven countries, including representatives from three international quality assurance groups. We collected error reports from RO‐ILS, SAFRON, AAPM TG publications, and other literature, including international audits. We focused on the subset of failure modes that impact whether the planned dose matches the dose received by the patient. We performed a failure‐mode‐and‐effects analysis (FMEA), estimating the severity (S), occurrence (O), and detectability (D) of each failure mode. Detectability was scored assuming that PSQA was not done but other routine clinical QA was performed, which allowed us to see the importance of PSQA for detecting each specific failure mode. We analyzed the risk priority number (RPN = O*S*D), O*S, and severity rankings to determine the priority of each failure mode.ResultsWe collected 394 error reports, which we categorized into 33 failure modes that underwent FMEA. Five failure modes were in the top ranks for both RPN and O*S analysis: four involving treatment planning system (TPS) commissioning and one regarding patient model errors. The highest‐ranking RPN failure modes were: TPS algorithm limitations, TPS commissioning errors [multileaf collimator (MLC) modeling, output factor, percent‐depth‐dose/tissue‐maximum‐ratio (PDD/TMR), off‐axis factor], and patient weight variation. The highest O*S failure modes were similar, with the addition of external patient position variation and incorrect linear accelerator isocenter and cGy/monitor units calibration. RPN and O*S analyses prioritized failure modes that impacted multiple patients with high occurrence and detectability scores, while severity analysis gave higher priority to single‐patient modes with high severity scores. The highest‐ranking severity modes were MLC sequence deletion, collision, and TPS isocenter incorrect.ConclusionWe have developed a list of failure modes critical to be detected during PSQA and ranked them in order of importance. The top failure modes emphasize the importance of utilizing a variety of treatment verification systems for PSQA, from secondary dose calculation through in‐vivo dosimetry, in order to detect all possible errors. For failure modes in the top quartile, PSQA is critical. Without adequate PSQA, these errors may go undetected unless caught by an external audit. This analysis can be useful for optimizing PSQA workflows and for designing evaluations of treatment verification systems, and will be used by the Joint AAPM‐ESTRO TG‐360 to determine an appropriate validation strategy.

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Clinical rationale for in vivo portal dosimetry in magnetic resonance guided online adaptive radiotherapy

Cited by 6 publications

References 33 publications

Experimental validation of multi-fraction online adaptations in magnetic resonance guided radiotherapy

Experimental validation of multi-fraction online adaptations in magnetic resonance guided radiotherapy

IPEM topical report: guidance for the clinical implementation of online treatment monitoring solutions for IMRT/VMAT

Which failures do patient‐specific quality assurance systems need to catch?

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