Radioluminescence-based fibre-optic dosimeters in radiotherapy: a review (incl. HYPERSCINT)

1. Small-Field Dosimetry, 2. Adaptive-RT (ex. MR-LINAC), 3. Treatment Plan (End-to-End) QA, 4. FLASH-RT / UHDR, 5. In Vivo Dosimetry, 6. Brachytherapy, 7. Commissioning, 8. Cherenkov Dosimetry, 9. Advanced Dosimetry, kV Photon, MeV Electron, MV Photon, Proton (and other Particules), Adaptive-RT, Advanced Optical Dosimetry, Custom Probe Development, Detector comparaison, Fundamental Research, LINAC Pulse Discrimination, Multi-point Dosimetry, Quality Assurance, Real-time Dosimetry Show more

In their comprehensive review, Veronese et al. examine the evolution and clinical application of radioluminescence-based fiber-optic dosimeters (FODs) in radiotherapy. These dosimeters have become essential tools in modern radiotherapy due to their capability for real-time, high-resolution dose measurements with minimal perturbation of the radiation field.

The authors discuss a wide range of scintillating materials, their properties, and dosimetric performance. They provide a thorough comparison of various solutions for addressing the stem-effect, a critical issue in fiber-optic dosimetry. Solutions reviewed include the hyperspectral approach (utilized by Medscint’s HYPERSCINT system), twin-fiber subtraction, optical filtering, dual-channel spectral discrimination, temporal gating, air-core light guides, and real-time Optically Stimulated Luminescence (rtOSL). Notably, the hyperspectral technology employed by HYPERSCINT represents a major advancement, effectively overcoming many limitations of other approaches by offering superior accuracy, simplified calibration procedures, and enhanced robustness, particularly valuable in complex clinical scenarios.

The review also emphasizes the growing adoption and diverse clinical applications of FODs, highlighting their significant role in improving treatment precision and patient safety. Clinical applications addressed in the review include small-field dosimetry, brachytherapy and in vivo dosimetry; advanced radiotherapy modalities such as intensity-modulated radiation therapy (IMRT), magnetic resonance-guided radiotherapy (MRgRT), hadron and proton therapies; and finally a special attention to MRI-Linac dosimetry and ultra-high dose rate (UHDR) or FLASH radiotherapy.

Radiation Measurements
Ivan Veronese (1), Claus E. Andersen (2), Enbang Li (3), Levi Madden (4), Alexandre M.C. Santos (5, 6, 7) | Department of Physics, University of Milan and National Institute for Nuclear Physics, Milano Unit, Italy, Department of Health Technology, Technical University of Denmark, Denmark, School of Physics, Faculty of Engineering and Information Sciences, University of Wollongong, Australia, Northern Sydney Cancer Centre, Royal North Shore Hospital, Australia, Australian Bragg Centre for Proton Therapy and Research, Australia, Radiation Oncology, Central Adelaide Local Heath Network, Australia, School of Physics, Chemistry and Earth Sciences, The University of Adelaide, Australia

High-throughput, low-cost FLASH: irradiation of Drosophila melanogaster with low-Energy X-rays using time structures spanning ConvDR and UHDR

4. FLASH-RT / UHDR, 5. In Vivo Dosimetry, kV Photon, Fundamental Research, Rabiobiology, Real-time Dosimetry Show more

This article explores the potential of using low-energy X-rays to deliver ultrahigh dose-rate (UHDR) FLASH radiotherapy using Drosophila melanogaster as a model. For this they have compared the effects of UHDR (210 Gy/s) and conventional dose rates (0.2–0.4 Gy/s) on the eclosion and lifespan of fly larvae. The results showed that larvae treated with UHDR had higher survival rates and longer lifespans, particularly at intermediate doses, indicating a normal tissue-sparing FLASH effect.

The Medscint scintillation dosimetry detector was used to measure the response to X-rays at a very high sampling rate to confirm the time structure of the delivered radiation (i.e. the pulse width and inter-pulse spacing). Along with film measurements, they also confirmed that the doses delivered with UHDR and CONV agreed within 0.1%.

Journal of Radiation Research
Alexander Hart (1), Jan P Dudzic (1), Jameson W Clarke (1), Jonathan Eby (2), Steve J Perlman (1), Magdalena Bazalova-Carter (1) | 1. University of Victoria, BC – CANADA, 2. University of Toronto, ON – CANADA

Characterization of a novel time-resolved, real-time scintillation dosimetry system (HYPERSCINT RP-FLASH) for ultra-high dose rate radiation therapy applications

4. FLASH-RT / UHDR, MeV Electron, Beam characterization, Commissioning, Detector comparaison, Energy Dependency, LINAC Pulse Discrimination, Quality Assurance, Real-time Dosimetry Show more

This study evaluates a novel scintillation dosimetry solution developed by Medscint for ultra-high dose rate (UHDR) radiotherapy, the HYPERSCINT RP-FLASH. The system was tested on an UHDR electron beamline, demonstrating dose linearity and independence from dose rate (1.8–1341 Gy/s) and dose per pulse (0.005–7.68 Gy) within ±3% tolerance. The system accurately measured doses per pulse up to 120 Hz.

With daily calibrations and specific correction factors, the system provides real-time, millisecond-resolved dosimetric measurements for pulsed conventional and UHDR beams, showing promise for applications in FLASH-RT.

PREPRINT
Alexander Baikalov (1,2,3), Daline Tho (1), Kevin Liu (1,4), Stefan Bartzsch (2,3), Sam Beddar (1,4), Emil Schüler (1,4) | 1. University of Texas MD Anderson Cancer Center, Houston, TX – USA, 2. Technical University of Munich – Germany, 3. German Research Center for Environmental Health, Neuherberg – Germany, 4. The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX – USA

Plastic scintillator dosimetry of ultrahigh dose-rate 200 MeV electrons at CLEAR

4. FLASH-RT / UHDR, MeV Electron, Custom Probe Development, Fundamental Research, Real-time Dosimetry Show more

Very high energy electron (VHEE) beams with energies greater than 100 MeV may be promising candidates for FLASH radiotherapy due to their favourable dose distributions and accessibility of ultrahigh dose-rates (UHDR). The standard dosimeters used for conventional radiotherapy, including ionization chambers and film, have limited application to UHDR radiotherapy due to deficits in dose rate independence and temporal resolution. The performance of PSDs in this work suggest they may be useful real-time dosimeters for applications in UHDR VHEE radiotherapy.

IEEE Xplore
Alexander Hart (1), Cloé Giguère (2,6), Joseph Bateman (3,4), Pierre Korysko (3,4), Wilfrid Farabolini (3), Vilde Rieker (3,5), Nolan Esplen (1), Roberto Corsini (3), Manjit Dosanjh (3,4), Luc Beaulieu(2,6), Magdalena Bazalova-Carter (1) | 1. Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada, 2. Département de Physique, de génie Physique et d’optique et Centre de Recherche sur le Cancer, Université Laval, Quebec, QC, Canada, 3. CERN, Geneva, Switzerland, 4. Department of Physics, University of Oxford, Oxford, United Kingdom, 5. Department of Physics, University of Oslo, Oslo, Norway, 6. Département de radio-oncologie et Axe Oncologie duCRCHUde Québec, CHUde Québec – Universit é Laval, Quebec, QC, Canada

Plastic scintillation detectors ready to shine as FLASH radiotherapy gathers momentum.

1. Small-Field Dosimetry, 4. FLASH-RT / UHDR, 9. Advanced Dosimetry, MeV Electron, MV Photon, Beam characterization, Fundamental Research, LINAC Pulse Discrimination, Quality Assurance, Real-time Dosimetry Show more

The team of University of Victoria’s XCITE Lab are using plastic scintillation detectors to provide real-time, small-field dosimetry in their FLASH radiotherapy experiments.

PHYSICS WORLD
| University of Victoria – XCITE Lab, Medscint

Implementation and validation of beam current transformer for Mobetron ultra-high dose rate electron beam monitoring using multi-detector approach

4. FLASH-RT / UHDR, MeV Electron, Beam characterization, Commissioning, Quality Assurance, Real-time Dosimetry Show more

To evaluate the performance of a custom beam current transformer (BCT) as a beam monitoring tool for the Mobetron electron radiation therapy system at ultra-high dose rates (UHDR) using a multi-detector comparison (plastic scintillators, ion chamber and film).

2022 COMP ANNUAL SCIENTIFIC MEETING
G.Famulari (1), K.Zerouali (1), J.Renaud (2), B.Muir (1), JF.Aubry (1), F.DeBlois (1), JF.Carrier (1) | 1 – Centre Hospitalier de l’Universite de Montreal (CHUM), Montreal, QC, CA, 2 – National Research Council Canada, Montreal, QC, CA

Technical note: Characterization and practical applications of a novel plastic scintillator for online dosimetry for an ultrahigh dose rate (FLASH)

4. FLASH-RT / UHDR, MeV Electron, Commissioning, Detector comparaison, Rabiobiology, Real-time Dosimetry Show more

Although FLASH radiation therapy is a promising novel technique, the ultrahigh pulsed dose rates mean that experimental dosimetry is very challenging. The plastic scintillator shows a linear and reproducible response and is able to accurately measure the radiation absorbed dose delivered by 16-MeV electrons at UHPDR. The dose is measured accurately in real time with a greater level of precision than that achieved with a radiochromic film.

Med Phys. 2022
Y.Poirier (1,2), J.Xu (1), S.Mossahebi (1), F.Therriault-Proulx (3), A.Sawant (1) | 1- Department of Radiation Oncology, University of Maryland School of Medicine, Maryland, USA, 2- Department of Medical Physics, McGill University, Quebec, Canada, 3- MEDSCINT, Quebec, Canada

Characterization of a Novel Plastic Scintillator for Instant Real- Time Dosimetry in Electron FLASH-RT

4. FLASH-RT / UHDR, 5. In Vivo Dosimetry, MeV Electron, Energy Dependency, Real-time Dosimetry Show more

Purpose was to characterize and validate the novel HYPERSCINT RP100 plastic dosimeter as a direct pulse counter and investigate its use as a real-time in-vivo dosimeter in FLASH-RT radiobiological experiments. In conclusions, the HYPERSCINT RP100 dosimeter accurately measured the delivered radiation absorbed dose under both characterization and biological experimental conditions, with a higher degree of reliability than conventional radiochromic film. Furthermore, its 500 Hz measurement frequency could directly and accurately measure the number of pulses delivered in real time. This shows its potential for real-time in-vivo dosimetry to verify accurate delivery during biological experiments and clinical treatments.

2021 COMP ANNUAL SCIENTIFIC MEETING
Y.Poirier (1), J.Xu (1), A.Ahmady (1), S.Mossahebi (1), H.Zhang (1), F.Therriault-Proulx (2), A.Sawant (1) | 1- University of Maryland School of Medicine, MD, USA , 2- McGill University, QC, Canada, 3- MEDSCINT, QC, Canada

Precise Pulse Delivery Control Using Monitor Units in Electron FLASH-RT

4. FLASH-RT / UHDR, MeV Electron, LINAC Pulse Discrimination, Real-time Dosimetry Show more

In electron FLASH-RT, precise delivery of the correct number of pulses is critical to accurate dose administration in preclinical radiobiological studies. This work investigates the use of LINAC monitor ion chambers to most precisely control FLASH pulse delivery. Calibrated plastic scintillation detector and EBT-XD Gafchromic films were used for online and passive dosimetry, respectively. The plastic scintillation detector also served as a direct pulse counter.

2021 AAPM ANNUAL MEETING
J.Xu, Y.Poirier, A.Sawant | University of Maryland School of Medicine, MD, USA

Novel Plastic Scintillator for Online Dosimetry in Electron FLASH-RT

4. FLASH-RT / UHDR, 5. In Vivo Dosimetry, MeV Electron, Energy Dependency, LINAC Pulse Discrimination, Rabiobiology, Real-time Dosimetry Show more

The accurate delivery of electrons at FLASH-RT dose rates in radiobiological experiments require new dosimeters that are capable of accurately measuring the radiation dose delivered at >0.55 Gy per pulse (>100 Gy/s) in real-time. The novel HYPERSCINT RP100 plastic dosimeter was able to accurately measure the delivered radiation absorbed dose under characterization and biological experimental conditions, with a higher degree of reliability than conventional radiochromic film. Furthermore, it was shown to directly and accurately measure the number of pulses delivered in real time. This shows potential for use as a real-time in-vivo dosimeter during biological experiments, as well as potential clinical applications.

2021 AAPM ANNUAL MEETING
Y.Poirier (1), J.Xu (1), A.Ahmady (1), S.Mossahebi (1), H.Zhang (1), F.Therriault-Proulx (2), A.Sawant (1) | 1- University of Maryland School of Medicine, Baltimore, MD, USA , 2- MEDSCINT, QC, CANADA