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 multi-point scintillation dosimetry research platform for a low-field MR-Linac

2. Adaptive-RT (ex. MR-LINAC), 5. In Vivo Dosimetry, 7. Commissioning, MV Photon, Adaptive-RT, Angular dependancy, Beam characterization, Commissioning, Quality Assurance, Real-time Dosimetry Show more

Plastic scintillation detectors (PSDs) are attractive for enhancing MRI-guided radiation therapy (MRgRT). A study evaluating the HYPERSCINT RP-200, a multi-probe PSD system, demonstrated excellent repeatability and minimal deviation in performance metrics such as detector response and percent depth dose (PDD). PSDs maintained consistent linearity across a broad range of monitor units and showcased high accuracy in gating experiments (ex. gating experiments where 400 cGy were delivered to isocenter : < 0.8 cGy variation for central axis measures and < 0.7 cGy for the gradient sampled region). These results highlight PSDs' huge potential in improving the precision and reliability of MRgRT, especially in complex real-time applications.

MEDICAL PHYSICS
Jennie Crosby (1), Chase Ruff (1), Ken Gregg (1), Jonathan Turcotte (2), Carri Glide-Hurst (1) | 1. Department of Human Oncology, University of Wisconsin-Madison, Madison, Wisconsin, USA, 2. Medscint, Québec, Quebec, Canada

Development of End-to-End Preclinical Treatment Verification Procedures, Traceable to NPL Air Kerma Primary Standard

1. Small-Field Dosimetry, 3. Treatment Plan (End-to-End) QA, 5. In Vivo Dosimetry, kV Photon, Adaptive-RT, Fundamental Research, Phantom QA, Quality Assurance, Rabiobiology, Real-time Dosimetry Show more

Dosimetry audits are an important tool to improve quality of reported results and to support standardization of preclinical radiation research. This work presents how the combination of passive and active detectors, such as the real-time HYPERSCINT scintillation dosimetry solution, with anatomically correct mouse phantoms are adequate for the development of End-to-End dosimetry audits for the independent verification of preclinical radiation treatments.

The traceability of the detectors’ calibration to primary standards strengthens the dosimetry chain in the validation of preclinical plans, and it is consistent with the current practice for dose traceability of clinical radiotherapy treatments. Their implementation at national and regional levels could lead to databases of anonymised records, which will positively impact the dissemination of best practices and sharing of validated results.

6th Conference on small animal precision image-guided radiotherapy
Ileana Silvestre Patallo (1), Rebecca Carter (2)(3), Andrew Nisbet (2), Anna Subiel (1), Giuseppe Schettino (1) | 1. National Physical Laboratory, UK, 2. University College London, UK, 3. Cancer Institut, UK

Investigation of temperature dependence of inorganic scintillators using the HYPERSCINT research platform

5. In Vivo Dosimetry, 6. Brachytherapy, 9. Advanced Dosimetry, MV Photon, Advanced Optical Dosimetry, Detector comparaison, Fundamental Research, Real-time Dosimetry Show more

The temperature dependence of four inorganic scintillation detectors was examined spectrally using the HYPERSCINT Research Platform 200 under 6 MV photon irradiations from a LINAC. After varying only the temperature of the detectors, all scintillators demonstrated linearity when the change in photon counts with temperature in the full-width at half maximum of their spectrum are integrated. Establishing the magnitude of the temperature dependence of the materials is critical to decide whether correction factors are required. This is especially true in applications such as brachytherapy, where detectors equilibrise to body temperature.

Radiation Measurements
Owen McLaughlin (1), Michael Martyn (1,2), Christoph Kleefeld (1), Mark Foley (1) | 1. Physics Unit, School of Natural Sciences, University of Galway, Galway, Ireland, 2. Galway Clinic, Doughiska, Galway, Ireland

Pre-clinical and clinical evaluation of the HYPERSCINT plastic scintillation dosimetry research platform for in vivo dosimetry during radiotherapy

5. In Vivo Dosimetry, MV Photon, Quality Assurance, Real-time Dosimetry Show more

The purpose of this work is to evaluate the HYPERSCINT HS-RP100 scintillation dosimetry research platform designed for clinical quality assurance (QA) for use in in vivo dosimetry measurements. The device correctly detected the treatment error when the heads were intentionally laterally shifted. In three canine clinical patients treated in multiple fractions.

J Appl Clin Med Phys. 2022
I.Schoepper (1), S.Dieterich (2), E.Alonzo Trestrail (3), M.Sean Kent (1) | Department of Radiation Oncology, University of California Davis School of Veterinary Medicine, Davis, California, USA, Department of Radiation Oncology, University of California Davis, Medical Center, Sacramento, California, USA, Pacific Crest Medical Physics, Chico, California, USA

Brachytherapy Technique Commissioning Using the HYPERSCINT Plastic Scintillation Detector

5. In Vivo Dosimetry, 6. Brachytherapy, 7. Commissioning, kV Photon, Commissioning, Detector comparaison, Quality Assurance Show more

Accurate dosimetry in brachytherapy is not an easy task, as most detectors exhibit volume averaging or energy dependence reducing their usability. Free from these limitations are plastic scintillation detectors, which makes them well suited for brachytherapy applications, either for in vivo dosimetry or commissioning. This work aims to determine if the HYPERSCINT scintillation dosimetry research platform can be used for brachytherapy dose measurement in the context of commissioning a new brachytherapy technique.

2020 AAPM ANNUAL MEETING
M.Goulet, N.Octave, P.Duguay-drouin | CISSS – Chaudiere-Appalaches, Lévis, QC, CA

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

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

On the use of a single-fiber multipoint plastic scintillation detector for 192Ir high-dose-rate brachytherapy

5. In Vivo Dosimetry, 6. Brachytherapy, 9. Advanced Dosimetry, kV Photon, Fundamental Research, Real-time Dosimetry Show more

The goal of this study was to prove the feasibility of using a single-fiber multipoint plastic scintillation detector as an in vivo verification tool during (192)Ir high-dose-rate brachytherapy treatments. The use of a multipoint plastic scintillation detector for high-dose-rate brachytherapy dosimetry is feasible. This detector shows great promise for development of in vivo applications for real-time verification of treatment delivery.

MEDICAL PHYSICS
F.Therriault-Proulx, S.Beddar, L.Beaulieu | Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA