Mechanical evaluation of the Bravos afterloader system for HDR brachytherapy

Bellezzo, Murillo; Baeza, J.A.; Voncken, Robert; Reniers, Brigitte; Verhaegen, Frank; Fonseca, Gabriel Paiva

doi:10.1016/j.brachy.2019.06.005

Cited by 12 publications

(22 citation statements)

References 14 publications

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“…Some clinics do not accept treatment plan dwell times shorter than 0.5 s due to the time it takes for the source to move between dwell positions (transit time) [61,62]. In addition, in modern afterloaders, the minimum dwell time depends on the distance between dwell positions [63]. The aim of measuring time is to ensure that the dwell times are correct.…”

Section: Dwell Time Measurementsmentioning

confidence: 99%

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In vivo dosimetry in brachytherapy: Requirements and future directions for research, development, and clinical practice

Fonseca

Johansen

Smith

et al. 2020

Physics and Imaging in Radiation Oncology

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Brachytherapy can deliver high doses to the target while sparing healthy tissues due to its steep dose gradient leading to excellent clinical outcome. Treatment accuracy depends on several manual steps making brachytherapy susceptible to operational mistakes. Currently, treatment delivery verification is not routinely available and has led, in some cases, to systematic errors going unnoticed for years. The brachytherapy community promoted developments in in vivo dosimetry (IVD) through research groups and small companies. Although very few of the systems have been used clinically, it was demonstrated that the likelihood of detecting deviations from the treatment plan increases significantly with time-resolved methods. Time-resolved methods could interrupt a treatment avoiding gross errors which is not possible with time-integrated dosimetry. In addition, lower experimental uncertainties can be achieved by using source-tracking instead of direct dose measurements. However, the detector position in relation to the patient anatomy remains a main source of uncertainty. The next steps towards clinical implementation will require clinical trials and systematic reporting of errors and nearmisses. It is of utmost importance for each IVD system that its sensitivity to different types of errors is well understood, so that end-users can select the most suitable method for their needs. This report aims to formulate requirements for the stakeholders (clinics, vendors, and researchers) to facilitate increased clinical use of IVD in brachytherapy. The report focuses on high dose-rate IVD in brachytherapy providing an overview and outlining the need for further development and research. ☆ During the 1st ESTRO Physics Workshop celebrated in November 2017 in Glasgow, Scotland, a task group was created to stimulate the wider adoption of in vivo dosimetry for radiotherapy. The members of this task group, authors of this report, were selected on the basis of their expertise to contribute relevant input to the area of study and their long-term experience in the clinical implementation of in vivo dosimetry systems.

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Section: Dwell Time Measurementsmentioning

confidence: 99%

“…However, dwell time corrections (e.g. rescaling due to air-kerma strength, transit time and minimum dwell time) [61,63] are applied just before the treatment by the treatment console. Therefore, measurements should be compared to the plan executed by the afterloader and this information should be accessible.…”

Section: Export Of Dwell Positions and Timesmentioning

confidence: 99%

In vivo dosimetry in brachytherapy: Requirements and future directions for research, development, and clinical practice

Fonseca

Johansen

Smith

et al. 2020

Physics and Imaging in Radiation Oncology

Self Cite

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show abstract

“…Afterloader QA can adopt video cameras instead of radiochromic films, allowing more precise dwell positions verification and also dwell times measurements. As an example, Varian Medical Systems (Palo Alto, CA) implemented a camera-based QA device (CamScale) to the Bravos afterloading system released in 2018 [25,26], which is not time resolved but already allows to easily perform multiple dwell position measurements and system recalibration when necessary (more on this topic in section 4.5.1). Studies have shown that the source cable movement can be measured using regular video cameras [27][28][29] and high speed cameras [25,30] .…”

Section: Advanced Treatment Workflow Methodsmentioning

confidence: 99%

“…As an example, Varian Medical Systems (Palo Alto, CA) implemented a camera-based QA device (CamScale) to the Bravos afterloading system released in 2018 [25,26], which is not time resolved but already allows to easily perform multiple dwell position measurements and system recalibration when necessary (more on this topic in section 4.5.1). Studies have shown that the source cable movement can be measured using regular video cameras [27][28][29] and high speed cameras [25,30] . Although such techniques are not practical for daily QA, the latter offers a precise and accurate method to evaluate dwell positions, dwell times and source speed profiles, which can be used to evaluate transit time dosimetry.…”

Section: Advanced Treatment Workflow Methodsmentioning

confidence: 99%

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Advanced methods for quality assurance and dose distribution improvement for high dose rate brachytherapy

Bellezzo¹

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People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:

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Practical experience commissioning MRI‐compatible tandem and ring applicators for use with the Bravos HDR afterloader

Fagerstrom

2023

J Applied Clin Med Phys

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Five complete MR‐conditionally approved ring sets, including fifteen tandems, and two additional rings, were commissioned at an institution intending to use them in an MRI planning environment with a Bravos HDR brachytherapy remote afterloader. Channel length, radiograph, autoradiograph, ring offset, and treatment interrupt measurements were performed, and applicators were assessed in both CT and MRI. During commissioning, one ring was found to be defective and was returned to the manufacturer for a replacement. The eventual complete applicator suite (including the replacement ring) was found to follow the manufacturer‐provided specifications, including those delineated in vendor‐provided 3D virtual models and those defined within the manufacturer's instructions for use documentation. Based on this work, an offset correction of −0.4 cm will be used for all tested rings using the Bravos system's internal distal dwell position correction feature during treatment preparation. This study reiterated the requirement for careful commissioning of each applicator intended for clinical service considering the intended use and the planned clinical environment and work processes.

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Mechanical evaluation of the Bravos afterloader system for HDR brachytherapy

Cited by 12 publications

References 14 publications

In vivo dosimetry in brachytherapy: Requirements and future directions for research, development, and clinical practice

In vivo dosimetry in brachytherapy: Requirements and future directions for research, development, and clinical practice

Advanced methods for quality assurance and dose distribution improvement for high dose rate brachytherapy

Practical experience commissioning MRI‐compatible tandem and ring applicators for use with the Bravos HDR afterloader

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