X-Tream dosimetry of synchrotron radiation with the PTW microDiamond

Davis, Joel; Petasecca, Marco; Cullen, Ashley; Paino, Jason; Archer, James; Rosenfeld, Anatoly; Lerch, Michael L. F

doi:10.1088/1748-0221/14/10/p10037

Cited by 15 publications

(15 citation statements)

References 12 publications

(16 reference statements)

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“…Despite these limitations for dosimetry applications the microDiamond remains an area of interest for QA with its response having recently been characterized for use in an MRI linac 24 and for the MRI-associated surface dose from electron contamination. 25 One of the key advantages of the PTW microDiamond is its high spatial resolution when operating in edge-on orientation, 21,26,27 however, the IAEA TRS-483 CoP requirement of a face-on orientation for all QA measurements means that this micron scale spatial resolution is unrealized. The edge-on and face-on orientation are referred to by the terms perpendicular and parallel orientation in the CoP, respectively.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the PTW microDiamond in edge‐on orientation for dosimetry in small fields

Brace

Alhujaili

Paino

et al. 2020

J Applied Clin Med Phys

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Purpose: The PTW microDiamond has an enhanced spatial resolution when operated in an edge-on orientation but is not typically utilized in this orientation due to the specifications of the IAEA TRS-483 code of practice for small field dosimetry. In this work the suitability of an edge-on orientation and advantages over the recommended face-on orientation will be presented. Methods: The PTW microDiamond in both orientations was compared on a Varian TrueBeam linac for: machine output factor (OF), percentage depth dose (PDD), and beam profile measurements from 10 × 10 cm 2 to a 0.5 × 0.5 cm 2 field size for 6X and 6FFF beam energies in a water tank. A quantification of the stem effect was performed in edge-on orientation along with tissue to phantom ratio (TPR) measurements. An extensive angular dependence study for the two orientations was also undertaken within two custom PMMA plastic cylindrical phantoms. Results: The OF of the PTW microDiamond in both orientations agrees within 1% down to the 2 × 2 cm 2 field size. The edge-on orientation overresponds in the build-up region but provides improved penumbra and has a maximum observed stem effect of 1%. In the edge-on orientation there is an angular independent response with a maximum of 2% variation down to a 2 × 2 cm 2 field. The PTW microDiamond in edge-on orientation for TPR measurements agreed to the CC01 ionization chamber within 1% for all field sizes. Conclusions: The microDiamond was shown to be suitable for small field dosimetry when operated in edge-on orientation. When edge-on, a significantly reduced angular dependence is observed with no significant stem effect, making it a more versatile QA instrument for rotational delivery techniques.

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Section: Introductionmentioning

confidence: 99%

Evaluation of the PTW microDiamond in edge‐on orientation for dosimetry in small fields

Brace

Alhujaili

Paino

et al. 2020

J Applied Clin Med Phys

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“…In vitro experiments, dosimetry and treatment verification. The dosimetric protocol for SBB and MRT at the IMBL is outlined in previous publications [25][26][27][28][29][30][31] . Briefly, it involves characterizing the pre-filtered SBB uniform in custom designed RMI-457 Gammex Solid Water ® phantoms (Gammex-RMI, Middleton, WI, USA) using a PinPoint ionization chamber (IC) (PTW 31014, Freiburg, Germany), calibrated to a traceable standard.…”

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confidence: 99%

Toward personalized synchrotron microbeam radiation therapy

Engels

Davis

et al. 2020

Sci Rep

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Synchrotron facilities produce ultra-high dose rate X-rays that can be used for selective cancer treatment when combined with micron-sized beams. Synchrotron microbeam radiation therapy (MRT) has been shown to inhibit cancer growth in small animals, whilst preserving healthy tissue function. However, the underlying mechanisms that produce successful MRT outcomes are not well understood, either in vitro or in vivo. this study provides new insights into the relationships between dosimetry, radiation transport simulations, in vitro cell response, and pre-clinical brain cancer survival using intracerebral gliosarcoma (9LGS) bearing rats. As part of this groundbreaking research, a new image-guided MRT technique was implemented for accurate tumor targeting combined with a pioneering assessment of tumor dose-coverage; an essential parameter for clinical radiotherapy. Based on the results of our study, we can now (for the first time) present clear and reproducible relationships between the in vitro cell response, tumor dose-volume coverage and survival post MRT irradiation of an aggressive and radioresistant brain cancer in a rodent model. our innovative and interdisciplinary approach is illustrated by the results of the first long-term MRT pre-clinical trial in Australia. Implementing personalized synchrotron MRT for brain cancer treatment will advance this international research effort towards clinical trials.

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“…At present there are a limited number of detector systems which are able to fulfil the aforementioned requirements, with the most notable of these being solid state in nature, such as silicon-based MOSFETs, strip detectors (Rosenfeld et al, 1999(Rosenfeld et al, , 2005Lerch et al, 2011;Petasecca et al, 2012;Fournier et al, 2017;Davis et al, 2018;Cameron et al, 2019) and commercial diamond-based detectors (PTW, 2019;Livingstone et al, 2016;Butler et al, 2018;Davis et al, 2019). Dosimetry protocols for synchrotron-based radiotherapy and synchrotron-based MRT can be found in the work presented by Prezado et al (2011) and Davis et al (2021), respectively.…”

Section: Introductionmentioning

confidence: 99%

“…In the case of the IMBL, the capability to connect a suitable detector directly to the control system of the fast safety shutter (FSS) enables personnel to limit exposure time to that of the FSS activation time, i.e. $15 to 20 ms (Livingstone et al, 2017;Davis et al, 2019). Such a setup would inherently link real-time beam monitoring to treatment QA and ensure the safety of an MRT patient as best practice dictates.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of silicon strip detectors in transmission mode for online beam monitoring in microbeam radiation therapy at the Australian Synchrotron

Davis¹,

Dipuglia²,

Cameron³

et al. 2022

J Synchrotron Rad

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Successful transition of synchrotron-based microbeam radiation therapy (MRT) from pre-clinical animal studies to human trials is dependent upon ensuring that there are sufficient and adequate measures in place for quality assurance purposes. Transmission detectors provide researchers and clinicians with a real-time quality assurance and beam-monitoring instrument to ensure safe and accurate dose delivery. In this work, the effect of transmission detectors of different thicknesses (10 and 375 µm) upon the photon energy spectra and dose deposition of spatially fractionated synchrotron radiation is quantified experimentally and by means of a dedicated Geant4 simulation study. The simulation and experimental results confirm that the presence of the 375 µm thick transmission detector results in an approximately 1–6% decrease in broad-beam and microbeam peak dose. The capability to account for the reduction in dose and change to the peak-to-valley dose ratio justifies the use of transmission detectors as thick as 375 µm in MRT provided that treatment planning systems are able to account for their presence. The simulation and experimental results confirm that the presence of the 10 µm thick transmission detector shows a negligible impact (<0.5%) on the photon energy spectra, dose delivery and microbeam structure for both broad-beam and microbeam cases. Whilst the use of 375 µm thick detectors would certainly be appropriate, based upon the idea of best practice the authors recommend that 10 µm thick transmission detectors of this sort be utilized as a real-time quality assurance and beam-monitoring tool during MRT.

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X-Tream dosimetry of synchrotron radiation with the PTW microDiamond

Cited by 15 publications

References 12 publications

Evaluation of the PTW microDiamond in edge‐on orientation for dosimetry in small fields

Evaluation of the PTW microDiamond in edge‐on orientation for dosimetry in small fields

Toward personalized synchrotron microbeam radiation therapy

Evaluation of silicon strip detectors in transmission mode for online beam monitoring in microbeam radiation therapy at the Australian Synchrotron

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