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

FLASH-RT, Fundamental research, SMALL-FIELD, MeV Electron, MV Photon, Beam characterization, Fundamental Research, LINAC Pulse Counting, 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

FLASH-RT, 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)

FLASH-RT, 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

FLASH-RT, 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

FLASH-RT, MeV Electron, LINAC Pulse Counting, 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

FLASH-RT, In Vivo Dosimetry, MeV Electron, Energy Dependency, LINAC Pulse Counting, 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

Investigation of the HyperscintTM Plastic Scintillation Dosimetry System Performance in a 15 MeV electron beam at FLASH dose rates

FLASH-RT, MeV Electron, Energy Dependency, Real-time Dosimetry Show more

The performance of the HYPERSCINT plastic scintillation dosimetry system in a 15 MeV electron beam operating at FLASH dose rates was investigated. The linac produced a 15 MeV electron FLASH beam with an average dose rate of ~250 Gy/s and dose per pulse between 1 Gy and 1.7 Gy, at the level just above the multi-leaf collimator. The HYPERSCINT plastic scintillator detector system agreed with OSLDs within 3.5% for 10 to 20 pulse FLASH deliveries using the standard dose rate calibration for both dosimeters.

2021 COMP ANNUAL SCIENTIFIC MEETING
C.Mendez, P.Petric, T.Karan, C.Duzenli | BC Cancer, Vancouver, BC, CA

EFLASH Dosimetry On a Conventional Linac Using Pulse-Gated Delivery

FLASH-RT, Fundamental research, MeV Electron, Detector comparaison, Energy Dependency, Fundamental Research, LINAC Pulse Counting, Real-time Dosimetry Show more

To build on previous experiments and improve reproducibility of electron FLASH delivery on a conventional linear accelerator, a pulse-gating circuit was constructed and tested with several dosimeters including : a 0.01cc volume ion chamber, optically stimulated luminescence dosimeters (OSLDs), Gafchromic MD film and a novel plastic scintillation detector with spectral analysis (HYPERSCINT).

2021 AAPM ANNUAL MEETING
C.Duzenli, C.Mendez, M.Petric, J.Sweeney, D.Ta, T.Karan | BC Cancer, Vancouver, BC, CANADA

On the nature of the light produced within PMMA optical light guides in scintillation fiber-optic dosimetry

Advanced Optical Dosimetry, Fundamental research, MeV Electron, MV Photon, Advanced Optical Dosimetry, Cherenkov, Energy Dependency, Fundamental Research Show more

The goal of this study was to evaluate the nature of the stem effect light produced within an optical fiber, to quantify its composition, and to evaluate the efficiency of the chromatic technique to remove the stem effect. The chromatic stem effect removal technique is accurate in most of the situations. However, noticeable differences were obtained between very specific high-energy irradiation conditions. It would be advantageous to implement an additional channel in the chromatic stem effect removal chain or implement a spectral approach to independently remove the Cerenkov and the fluorescence components from the signal of interest. This would increase the accuracy and versatility of the actual chromatic stem effect removal technique.

PHYSICS IN MEDICINE & BIOLOGY
F.Therriault-Proulx (1)(2), L.Beaulieu (2)(3), L.Archambault (2)(3), S.Beddar (4)(1) | 1- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA, 2- Département de Physique, de Génie Physique et d’Optique, Université Laval, Québec, Québec, Canada, 3- Département de Radio-Oncologie, Hôtel-Dieu de Québec, Centre Hospitalier Universitaire de Québec, Québec, Canada

Review of plastic and liquid scintillation dosimetry for photon, electron, and proton therapy

Fundamental research, kV Photon, MeV Electron, MV Photon, Proton, Fundamental Research Show more

While scintillation dosimetry has been around for decades, the need for a dosimeter tailored to the reality of modern radiation therapy-in particular a real-time, water-equivalent, energy-independent dosimeter with high spatial resolution-has generated renewed interest in scintillators over the last 10 years. This topical review is intended to provide the medical physics community with a wide overview of scintillation physics, related optical concepts, and applications of plastic scintillation dosimetry.

PHYSICS IN MEDICINE & BIOLOGY
L Beaulieu (1,2), S Beddar (3,4) | 1- Département de physique, génie physique et optique, et Centre de recherche sur le cancer, Université Laval, Québec, CA , 2- Département de radio-oncologie et Axe Oncologie du CRCHU de Québec, QC, CA, 3- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA, 4- The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, USA