X-Tream dosimetry of highly brilliant X-ray microbeams in the MRT hutch of the Australian Synchrotron

et al. 2019

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Microbeam radiation therapy is a novel pre-clinical external beam therapy that uses high-brilliance synchrotron X-rays to deliver the necessary high dose rates. The unique conditions of high dose rate and high spatial fractionation demand a new class of detector to experimentally measure important beam quality parameters. Here we demonstrate the highest spatial resolution plastic scintillator fibre-optic dosimeter found in the literature to date and tested it on the Imaging and Medical Beam-Line at the Australian Synchrotron in a X-ray beam where the irradiation dose rate was 4435 Gy/s. With a one-dimensional spatial resolution of 10 μ m the detector is able to resolve the individual microbeams (53.7 ± 0.4 μ m wide), and measure the peak-to-valley dose ratio to be 55 ± 17. We also investigate the role of radioluminescence in the optical fibre used to transport the scintillation photons, and conclude that it creates a significant contribution to the total light detected.

Section: Resultsmentioning

confidence: 96%

High spatial resolution scintillator dosimetry of synchrotron microbeams

Archer

et al. 2019

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“…The 50 µm Single Strip Detector (SSD) designed at CMRP and fabricated at SPA-BIT, Kiev, Ukraine has been previously shown to be a promising candidate. It has successfully measured FWHM and PVDR of microbeams in real time, making it ideal as an dosimetric analysis tool [15]. However, in order to achieve the necessary spatial resolution for microbeam profiling the device must be operated in edge-on mode which may lead to measured profile artefacts [16] [17].…”

Section: Introductionmentioning

confidence: 99%

Characterisation and evaluation of a PNP strip detector for synchrotron microbeam radiation therapy

Biomed. Phys. Eng. Express

Paino

Dipuglia

et al. 2018

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The Quality Assurance requirements of detectors for Synchrotron Micro-beam Radiation Therapy are such that there are limited commercial systems available. The high intensity and spatial fractionation of synchrotron microbeams requires detectors be radiation hard and capable of measuring high dose gradients with high spatial resolution sensitivity. Silicon single strip detectors are a promising candidate for such applications. The PNP strip detector is an alternative design of an already proven technology and is assessed on its contextual viability. In this study, the electrical and charge collection efficiency properties of the device are characterised. In addition, a dedicated TCAD model is used to support ion beam induced charge measurements to determine the spatial resolution of the detector. Lastly, the detector was used to measure the full width half maximum and peak to valley dose ratio for microbeams with only a slight over response. With the exception of radiation hardness the PNP detector is a promising candidate for quality assurance in microbeam radiation therapy.

“…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.…”

mentioning

confidence: 99%

“…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. A micron-scale spatial resolution X-Tream dosimeter 27,28 was then calibrated at the same reference conditions: 20 × 20 mm 2 SBB field at a 20 mm depth. After the insertion of the MSC, the MRT field was characterized using the X-Tream system at 20 mm depth.…”

mentioning

confidence: 99%

Toward personalized synchrotron microbeam radiation therapy

Engels

et al. 2020

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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.