Determination of the optimal tolerance for MLC positioning in sliding window and VMAT techniques

Hernandez, V.; Abella, Raúl; Calvo, J.F.; urado-Bruggeman, D.; Sancho, I.; Carrasco, P.

doi:10.1016/s0167-8140(15)40245-2

Cited by 4 publications

(4 citation statements)

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“…To verify the predictions from the emulator they were compared to results from log files for both Elekta and Varian linacs. Varian log files were analysed with in-house software [21] and log files from Elekta were recorded with the service graphing module of the linac controller (Integrity 1.2).…”

Section: Methodsmentioning

confidence: 99%

Comparison of complexity metrics for multi-institutional evaluations of treatment plans in radiotherapy

Hernández

Saez

Pasler³

et al. 2018

Physics and Imaging in Radiation Oncology

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Background and purpose: It is known that intensity-modulated radiotherapy plans that are highly complex might be less accurate in dose calculation and treatment delivery. Multiple complexity metrics have been proposed, but the relationships between them have not been thoroughly investigated. This study investigated these relationships in multi-institutional comparisons of treatment plans, where plans from multiple treatment planning systems (TPSs) are typically evaluated. Materials and methods: A program was developed to compute several complexity indices and provide analysis of dynamic plan parameters. This in-house software was used to analyse plans from a recent multi-institutional audit. Additionally, 100 clinical volumetric modulated arc therapy (VMAT) plans from two institutions using different TPSs were analysed. Results: All plans produced satisfactory pre-treatment verification results and, hence, complexity metrics could not be used to predict plans failing QA. Regarding the relationship among complexity indices, some very strong correlations were found (r > 0.9 with p < 0.01). However, some relevant discrepancies between complexity indices were obtained, even with negative correlation coefficients (r ∼ −0.6) which were expected to be positive. These discrepancies could be explained because each complexity index focused on different features of the plan and different TPSs prioritised modulation of different plan parameters. Conclusions: Some complexity indices provided similar information and can be considered equivalent. However, indices that focused on different plan parameters yielded different results and it was unclear which complexity index should be used. Careful consideration should be given to the use of complexity metrics in multi-institutional studies.

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Section: Methodsmentioning

confidence: 99%

Comparison of complexity metrics for multi-institutional evaluations of treatment plans in radiotherapy

Hernández

Saez

Pasler³

et al. 2018

Physics and Imaging in Radiation Oncology

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“…In summary, various studies were conducted in this area and revealed different results regarding the correlation between plan complexity indices and QA metrics [65][66][67][68][69][70][71][72][73][74][75][76][77][78][79]. We believe, these differences may depend on the linac model and its commissioning plus TPS limitations such as beam model, dose engine, and algorithm [71,80,81].…”

Section: Modulation Indicesmentioning

confidence: 92%

Parameters Affecting Pre-Treatment Dosimetry Verification

Parsai¹,

Salari²

2022

Dosimetry

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To assure the accuracy and safety of radiation delivery, it is highly recommended to perform pretreatment verification for complex treatment methods such as intensity-modulated radiation therapy (IMRT) or volumetric-modulated arc therapy (VMAT) to detect any potential errors in the treatment planning process and machine deliverability. It is expected that a qualified medical physicist is aware of the underlying scientific principles of imaging and therapeutic processes to perform or supervise technical aspects of pretreatment procedures to ensure safe and effective delivery of the treatment. For this purpose, several guidelines have been published to help direct medical physicists to evaluate the accuracy of treatment planning system (TPS) in the calculation of radiation dose, and dosimetry equipment to avoid possible errors. This will require a clear understanding of abilities as well as the limitations of each TPS, the dosimetry equipment at hand, and the gamma index to perform a comprehensive pre-treatment verification.

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“…Multi-institutional studies demonstrated how log file evaluation can be used for inter-departmental comparison [99] , [100] , [101] , [102] . Results from log file analysis can help to identify sources of errors during treatment delivery and were shown to correlate with time-resolved gamma analysis [101] .…”

Section: Phantom-less Methods For Dosimetry Auditsmentioning

confidence: 99%

Novel methodologies for dosimetry audits: Adapting to advanced radiotherapy techniques

Pasler¹,

Hernández

Jornet

et al. 2018

Physics and Imaging in Radiation Oncology

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With new radiotherapy techniques, treatment delivery is becoming more complex and accordingly, these treatment techniques require dosimetry audits to test advanced aspects of the delivery to ensure best practice and safe patient treatment. This review of novel methodologies for dosimetry audits for advanced radiotherapy techniques includes recent developments and future techniques to be applied in dosimetry audits. Phantom-based methods (i.e. phantom-detector combinations) including independent audit equipment and local measurement equipment as well as phantom-less methods (i.e. portal dosimetry, transmission detectors and log files) are presented and discussed. Methodologies for both conventional linear accelerator (linacs) and new types of delivery units, i.e. Tomotherapy, stereotactic devices and MR-linacs, are reviewed. Novel dosimetry audit techniques such as portal dosimetry or log file evaluation have the potential to allow parallel auditing (i.e. performing an audit at multiple institutions at the same time), automation of data analysis and evaluation of multiple steps of the radiotherapy treatment chain. These methods could also significantly reduce the time needed for audit and increase the information gained. However, to maximise the potential, further development and harmonisation of dosimetry audit techniques are required before these novel methodologies can be applied.

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Determination of the optimal tolerance for MLC positioning in sliding window and VMAT techniques

Cited by 4 publications

References 0 publications

Comparison of complexity metrics for multi-institutional evaluations of treatment plans in radiotherapy

Comparison of complexity metrics for multi-institutional evaluations of treatment plans in radiotherapy

Parameters Affecting Pre-Treatment Dosimetry Verification

Novel methodologies for dosimetry audits: Adapting to advanced radiotherapy techniques

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