Validation and IMRT/VMAT delivery quality of a preconfigured fast‐rotating O‐ring linac system

Roover, Robin De; Crijns, Wouter; Poels, Kenneth; Michiels, Steven; Nulens, A.; Vanstraelen, Bianca; Petillion, S.; Brabandere, Marisol De; Haustermans, Karin; Depuydt, Tom

doi:10.1002/mp.13282

Cited by 43 publications

(62 citation statements)

References 39 publications

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“…Thus, exhaustive end‐to‐end tests and initial characterization of a large range of patient‐specific quality assurance tests may be more reflective of beam model verification. Other work that also details clinically acceptable agreement of validation measurements with the pre‐defined TPS is described by Roover et al and employs end‐end tests, IMRT/VMAT validation, and external dosimetric audits on the Halcyon system . We did not examine the minimum data requirements for spot‐checking this system, and should be the focus of future work.…”

Section: Discussionmentioning

confidence: 99%

“…Other work that also details clinically acceptable agreement of validation measurements with the pre-defined TPS is described by Roover et al and employs end-end tests, IMRT/VMAT validation, and external dosimetric audits on the Halcyon system. 19 We did not examine the minimum data requirements for spot-checking this system, and should be the focus of future work. Since the completion of this work, ongoing quality assurance has not indicated the need to change any of the pre-determined beam data in the clinical system.…”

Section: Discussionmentioning

confidence: 99%

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Experience in commissioning the halcyon linac

Netherton

Gao

et al. 2019

Medical Physics

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Purpose This manuscript describes the experience of two institutions in commissioning the new HalcyonTM platform. Its purpose is to: (a) validate the pre‐defined beam data, (b) compare relevant commissioning data acquired independently by two separate institutions, and (c) report on any significant differences in commissioning between the Halcyon linear accelerator and other medical linear accelerators. Methods Extensive beam measurements, testing of mechanical and imaging systems, including the multi‐leaf collimator (MLC), were performed at the two institutions independently. The results were compared with published recommendations as well. When changes in standard practice were necessitated by the design of the new system, the efficacy of such changes was evaluated as compared to published approaches (guidelines or vendor documentation). Results Given the proper choice of detectors, good agreement was found between the respective experimental data and the treatment planning system calculations, and between independent measurements by the two institutions. MLC testing, MV imaging, and mechanical system showed unique characteristics that are different from the traditional C‐arm linacs. Although the same methodologies and physics equipment can generally be used for commissioning the Halcyon, some adaptation of previous practices and development of new methods were also necessary. Conclusions We have shown that the vendor pre‐loaded data agree well with the independent measured ones during the commission process. This verifies that a data validation instead of a full‐data commissioning process may be a more efficient approach for the Halcyon. Measurement results could be used as a reference for future Halcyon users.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Experience in commissioning the halcyon linac

Netherton

Gao

et al. 2019

Medical Physics

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“…Halcyon plans: The Halcyon is a ring-based delivery system [13,[22][23][24]. It consists of a linear accelerator capable of producing a 6MV flattening filter-free (FFF) photon beam delivering (when calibrated to deliver 1.0Gy per 100 monitor units (MU) at the reference conditions of source-surface distance (SSD) 100 cm at d max depth of 1.3 cm) a maximum dose rate of 800MU/min.…”

Section: The Treatment Planning Techniques and Featuresmentioning

confidence: 99%

Treatment planning comparison of volumetric modulated arc therapy employing a dual-layer stacked multi-leaf collimator and helical tomotherapy for cervix uteri

et al. 2020

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Purpose: To ascertain the dosimetric performance of a new delivery system (the Halcyon system, H) equipped with dual-layer stacked multi-leaf collimator (MLC) for risk-adapted targets in cervix uteri cancer patients compared to another ring-based system in clinical operation (Helical Tomotherapy, HT). Methods: Twenty patients were retrospectively included in a treatment planning study (10 with positive lymph nodes and 10 without). The dose prescription (45Gy to the primary tumour volume and a simultaneously integrated boost up to 55Gy for the positive patients) and the clinical planning objectives were defined consistently as recommended by an ongoing multicentric clinical trial. Halcyon plans were optimised for the volumetric modulated arc therapy. The plan comparison was performed employing the quantitative analysis of the dose-volume histograms.Results: The coverage of the primary and nodal target volumes was comparable for both techniques and both subsets of patients. The primary planning target volume (PTV) receiving at least 95% of the prescription isodose ranged from 97.2 ± 1.1% (node-negative) to 99.1 ± 1.2% (node-positive) for H and from 96.5 ± 1.9% (node-negative) to 98.3 ± 0.9% (node-positive) for HT. The uncertainty is expressed at one standard deviation from the cohort of patient per each group. For the nodal clinical target volumes, the dose received by 98% of the planning target volume ranged 55.5 ± 0.1 to 56.0 ± 0.8Gy for H and HT, respectively. The only significant and potentially relevant differences were observed for the bowels. In this case, V 40Gy resulted 226.3 ± 35.9 and 186.9 ± 115.9 cm 3 for the node-positive and node-negative patients respectively for Halcyon. The corresponding findings for HT were: 258.9 ± 60.5 and 224.9 ± 102.2 cm 3 . On the contrary, V 15Gy resulted 1279.7 ± 296.5 and 1557.2 ± 359.9 cm 3 for HT and H respectively for node-positive and 1010.8 ± 320.9 versus 1203.8 ± 332.8 cm 3 for node-negative. Conclusion: This retrospective treatment planning study, based on the dose constraints derived from the Embrace II study protocol, suggested the essential equivalence between Halcyon based and Helical Tomotherapy based plans for the intensity-modulated rotational treatment of cervix uteri cancer. Different levels of sparing were observed for the bowels with H better protecting in the high-dose region and HT in the mid-low dose regions. The clinical impact of these differences should be further addressed.

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“…There are a number of publications that either evaluate the operation of the Halcyon or provide recommendations on its clinical use . A recent publication provided a risk assessment of Halcyon acceptance testing and commissioning processes using the TG‐100 methodology .…”

Section: Introductionmentioning

confidence: 99%

“…There are a number of publications that either evaluate the operation of the Halcyon or provide recommendations on its clinical use. [1][2][3][4][5][6][7][8][9][10][11] A recent publication provided a risk assessment of Halcyon acceptance testing and commissioning processes using the TG-100 methodology. 12 In that work, 142 failure modes were identified with the top risk priority number (RPN) values ranging from 85.5 to 95.0 for the acceptance testing and commissioning, respectively.…”

Section: Introductionmentioning

confidence: 99%

Clinical safety assessment of the Halcyon system

et al. 2019

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Purpose The Halcyon consists of precommissioned linear accelerator and treatment planning algorithms that were designed to simplify the acceptance, commissioning, and clinical workflow for image‐guided intensity‐modulated radiotherapy. The purpose of this work was to perform a comprehensive safety assessment for the clinical use of the Halcyon. Methods Systems‐Theoretic Process Analysis was used as the safety assessment tool. As part of the analysis, a number of control loops and control actions are created to describe system function. Safety is assessed by determining unsafe control actions and a corresponding list of causal scenarios that leads to accidents. The scope of the analysis was from the acceptance of the Halcyon to routine patient treatments. All aspects of treating patients were considered including the roles of physicians, physicists, dosimetrists, and therapists. The analysis was completed by four physicists with input from other members of the radiation therapy team. The causal scenarios were summarized using the causality categories from the consensus recommendations for incident learning database structures in radiation oncology (Med Phys, Vol. 39, No. 12, Dec 2012). Results Twenty‐three (23) control loops containing 52 control actions were created for the clinical use of the Halcyon. One hundred forty‐four (144) unsafe control actions were identified with 385 associated causal scenarios. Twenty‐seven percent (27%) of the causal scenarios were related to equipment technical issues, while 73% of the causal scenarios were predominantly related to procedural issues, human behavior, and organizational management. Conclusions For routine clinical use of closed or largely automated radiation therapy equipment, the majority of safety concerns is related to nontechnical issues. The Halcyon and other similar systems may present opportunities to streamline, reduce, or eliminate some traditional equipment commissioning and routine quality assurance activities in exchange for an increased focus on issues related to organizational management, procedures, and human behavior.

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Validation and IMRT/VMAT delivery quality of a preconfigured fast‐rotating O‐ring linac system

Cited by 43 publications

References 39 publications

Experience in commissioning the halcyon linac

Experience in commissioning the halcyon linac

Treatment planning comparison of volumetric modulated arc therapy employing a dual-layer stacked multi-leaf collimator and helical tomotherapy for cervix uteri

Clinical safety assessment of the Halcyon system

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