Design and testing of a phantom and instrumented gynecological applicator based on GaN dosimeter for use in high dose rate brachytherapy quality assurance

Guiral, Pierrick; Ribouton, J.; Jalade, P.; Wang, R.; Galvan, Jean‐Marc; Lu, Guo‐Neng; Pittet, Patrick; Rivoire, A.; Gindraux, L.

doi:10.1118/1.4961393

Cited by 26 publications

(51 citation statements)

References 34 publications

(39 reference statements)

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“…Measurements for dwell time verification in Ref. 26 were done for a 24 dwell-position protocol with a 5-s dwell time covering 60 mm of distances to the source. The findings in Ref.…”

Section: E Planned Vs Measured Dwell Timementioning

confidence: 99%

“…Furthermore, the effect of having a 2.5-mm dwell position step in Ref. 26 produces a more pronounced dose gradient between two subsequent dwell positions, and as a result, an easier detection. In this study, a 1-mm step between two dwell positions was used.…”

Section: E Planned Vs Measured Dwell Timementioning

confidence: 99%

“…Additionally, previous work explored the sourcetracking capacity of different detectors in HDR brachytherapy. [23][24][25][26][27][28] Some studies used an array of dosimeters placed on the patient's skin, and others a flat-panel detector. In a study of source-position tracking with a single-point detector in HDR brachytherapy, Johansen et al 24 used the dose values from the treatment planning system to develop a method to determine average source shifts within catheters.…”

Section: Introductionmentioning

confidence: 99%

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Dosimetric performance of a multipoint plastic scintillator dosimeter as a tool for real‐time source tracking in high dose rate Ir brachytherapy

et al. 2020

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This study aims to present the performance of a multipoint plastic scintillation detector (mPSD) as a tool for real-time dose measurements (covering three orders of magnitude in dose rate), source-position triangulation, and dwell time assessment in high dose rate (HDR) brachytherapy. Methods: A previously characterized and optimized three-point sensor system was used for HDR brachytherapy measurements. The detector was composed of three scintillators: BCF60, BCF12, and BCF10. Scintillation light was transmitted through a single 1-mm-diameter clear optical fiber and read by a compact assembly of photomultiplier tubes (PMTs). Each component was numerically optimized to allow for signal deconvolution using a multispectral approach, taking care of the Cerenkov stem effect as well as extracting the dose from each scintillator. The PMTs were read simultaneously using a data acquisition board at a rate of 100 KHz and controlled with in-house software based on Python. An 192 Ir source (Flexitron, Elekta-Brachy) was remotely controlled and sent to various positions in a in-house PMMA holder, ensuring 0.1 mm positional accuracy. Dose measurements covering a range of 10 cm of source movement were carried out according to TG-43 U1 recommendations. Water measurements were performed in order to: (a) characterize the system's response in terms of angular dependence; (b) obtain the relative contribution of positioning and measurement uncertainties to the total system uncertainty; (c) assess the system's temporal resolution; and (d) track the source position in real time. The triangulation principle was applied to report the source position in three-dimensional space. Results: As expected, the positioning uncertainty dominated close to the source, whereas the measurement uncertainty dominated at larger distances. A maximum measurement uncertainty of 17 % was observed for the BCF60 scintillator at 10 cm from the source. Based on the uncertainty chain, the best compromises between positioning and measurement uncertainties were reached at 17.2, 17.4, and 17.5 mm for the BCF10, BCF12, and BCF60 scintillators, respectively, which also corresponded to the recommended optimal distances to the source for calibration purposes. The detector further exhibited no angular dependence. All dose values were found to be within 2% of the dose value at 90. In the experiments performed for source-position determination, the system provided an average location with a standard deviation under 1.7 mm. The maximum observed differences between measured and expected values were 1.82 and 1.8 mm in the x-and z-directions, respectively. Deviations between the mPSD measurements and expected TG-43 values were below 5% in all the explored measurement conditions. With regard to dwell time measurement accuracy, the maximum deviation observed at all distances was 0.56 AE 0.25 s, with a weighted average of the three scintillators below 0.33 AE 0.37 s at all distances covered in this study. Conclusions: Real-time HDR brachytherapy measurements were performed with a...

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“…Measurements for dwell time verification in Ref. 26 were done for a 24 dwell-position protocol with a 5-s dwell time covering 60 mm of distances to the source. The findings in Ref.…”

Section: E Planned Vs Measured Dwell Timementioning

confidence: 99%

Section: E Planned Vs Measured Dwell Timementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dosimetric performance of a multipoint plastic scintillator dosimeter as a tool for real‐time source tracking in high dose rate Ir brachytherapy

et al. 2020

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“…To the best of our knowledge, it is the first time ever that such a system is presented in literature. In fact, Wang et al [23] and Guiral et al [24] also equipped a commercial MVC applicator with four GaN-based dosimeters. They respectively.…”

Section: Discussionmentioning

confidence: 99%

An innovative gynecological HDR brachytherapy applicator system for treatment delivery and real-time verification

et al. 2019

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“…Dose rate at dwell position level: Verification of the dose and dose rate is the most basic level of feedback available from time-resolved IVD. Acquisition with a subsecond rate enables measurement of the dose rate for each dwell position [26]. Hence, a direct comparison of the expected and measured dose rate can be made at the dwell position level.…”

Section: Time-resolved Point/multipoint Dosimetrymentioning

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

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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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Design and testing of a phantom and instrumented gynecological applicator based on GaN dosimeter for use in high dose rate brachytherapy quality assurance

Cited by 26 publications

References 34 publications

Dosimetric performance of a multipoint plastic scintillator dosimeter as a tool for real‐time source tracking in high dose rate Ir brachytherapy

Dosimetric performance of a multipoint plastic scintillator dosimeter as a tool for real‐time source tracking in high dose rate Ir brachytherapy

An innovative gynecological HDR brachytherapy applicator system for treatment delivery and real-time verification

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

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