Field output correction factors using a fully characterized plastic scintillation detector (HYPERSCINT)

1. Small-Field Dosimetry, 7. Commissioning, 9. Advanced Dosimetry, MeV Electron, MV Photon, Beam characterization, Commissioning, Detector comparaison, Energy Dependency, Monte Carlo Simulations, Quality Assurance Show more

As small fields become increasingly important in radiation therapy, accurate dosimetry is essential for ensuring precise dose calculation and treatment optimization. Despite the availability of small volume detectors, small field dosimetry remains challenging. The new plastic scintillation detector (PSD) from the HYPERCINT RP-200 platform from Medscint offers a promising solution with minimal correction requirements for small field measurements.

This study focused on characterizing the field output correction factors of the PSD across a wide range of field sizes and demonstrating its potential for determining correction factors for other small field detectors. Monte Carlo simulations and experimental comparisons were used to assess the system’s performance. The PSD exhibited near-unity correction factors (1.002 to 0.999) across field sizes between 0.6×0.6 cm² and 30×30 cm², with an impressive total uncertainty of 0.5%.

The PSD is shown to be a highly accurate and reliable detector for small field dosimetry, and it can also be used to determine correction factors for other dosimeters with great precision.

MEDICAL PHYSICS (AAPM)
Luc Gingras (1,2), Yunuen Cervantes (1,2,3), Frederic Beaulieu (1,2), Magali Besnier (1,2), Benjamin Coté (4), Simon Lambert-Girard (4), Danahé LeBlanc (4), Yoan LeChasseur (4), François Therriault-Proulx (4), Luc Beaulieu (1,2,3), Louis Archambault (1,2,3) | 1. CHU de Québec–Université Laval, Québec – Canada, 2. Centre de recherche du CHU de Québec, Québec – Canada, 3. Université Laval, Québec – Canada, 4. Medscint, Québec – Canada

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

Temporal, spatial, and motion-included scintillation-based QA for an MR-linac

2. Adaptive-RT (ex. MR-LINAC), 3. Treatment Plan (End-to-End) QA, 7. Commissioning, 9. Advanced Dosimetry, MeV Electron, MV Photon, Adaptive-RT, Multi-point Dosimetry, Phantom QA, Quality Assurance, Real-time Dosimetry Show more

Modern adaptive radiotherapy techniques enhance healthy tissue sparing but introduce increased treatment complexity, requiring precise dosimetric validation. To address this, the MRI⁴ᴰ scintillator cassette in collaboration with IBA QUASAR and MEDSCINT is an innovative device integrating four MR-compatible plastic scintillation detectors (PSDs) and a radiochromic film. This device seamlessly works with the IBA QUASAR MRI⁴ᴰ Motion Phantom for comprehensive spatial, temporal, and motion-included dosimetry.

In this webinar, Prescilla Uijtewaal, PhD
explains her experience with the solution, showcasing the performance of the HYPERSCINT RP-200 scintillation dosimetry research platform in a 1.5T MR-linac and demonstrate the capabilities of the MRI⁴ᴰ scintillator cassette, and more.

WEBINAR – Physics World Magazine
Prescilla Uijtewaal, Martin Fast | University Medical Center Utrecht (UMCU) – Netherlands

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

Experimental dosimetric verification of the intra-fraction drift correction on the 1.5 T MR-linac

2. Adaptive-RT (ex. MR-LINAC), 7. Commissioning, MV Photon, Adaptive-RT, Commissioning, Multi-point Dosimetry, Quality Assurance, Real-time Dosimetry Show more

MRI-guided online adaptive treatments can improve tumor targeting by adjusting treatment plans in real-time based on cine MR-scans. And to correct the intra-fraction motion, Elekta AB introduced the intra-fraction drift correction (IDC) functionality for the 1.5 T Unity MR-linac.

The IDC is a valuable functionality for fast intra-fraction adaptations and this research experimentally verifies the geometric and dosimetric accuracy of the IDC process using film, scintillation, and diode dosimetry.

ESTRO 2024 Annual Congress
Madelon van den Dobbelsteen, Sara L. Hackett, Stijn Oolbekkink, Bram van Asselen, Prescilla Uijtewaal, Martin F. Fast, Bas W. Raaymakers | University Medical Center Utrecht, Radiotherapy, Utrecht, Netherlands

Evaluation of the HYPERSCINT scintillation dosimetry platform for small-field characterization of a Leksell GAMMA KNIFE

1. Small-Field Dosimetry, 7. Commissioning, MV Photon, Beam characterization, Commissioning, Phantom QA, Quality Assurance Show more

The performance of the HYPERSCINT RP-200 with the 0.5mm x 0.5mm detector was evaluated for the characterization of small radiation fields administered using a Leksell Gamma Knife Perfexion radiosurgery device. Overall, our results show that the detector response was in close agreement with Gamma Knife Monte Carlo reference data and film measurements. Based on the obtained results, the plastic scintillation detector shows the potential for rapid validation of output factors and validation of film measurements as well its use in challenging small-field situations encountered with the Gamma Knife.

ISRS 2024 – New York
Mathieu GUILLOT (1), Patrick DELAGE (1), Vincent HUBERT-TREMBLAY (1), Francois THERRIAULT-PROULX (2), Danahé LEBLANC (2) | CHUS – Sherbrooke, Canada, Medscint – Québec, Canada

Performance characterization of a novel hybrid dosimetry insert for simultaneous spatial, temporal, and motion-included dosimetry for MR-linac

2. Adaptive-RT (ex. MR-LINAC), 3. Treatment Plan (End-to-End) QA, 7. Commissioning, MeV Electron, MV Photon, Adaptive-RT, Commissioning, Multi-point Dosimetry, Phantom QA, Real-time Dosimetry Show more

The increased treatment complexity and the motion-delivery interplay during stereotactic body radiotherapy (SBRT) on an MR-linac treatments require MR-compatible motion phantoms with time-resolved dosimeters to validate end-to-end workflows. This study demonstrates the excellent suitability of a the Medscint novel hybrid film-scintillators cassette for simultaneous multi-spatial, temporal, and motion-included dosimetry.

MEDICAL PHYSICS
Prescilla Uijtewaal (1), Pim Borman (1), Benjamin Côté (2), Yoan LeChasseur (2), François Therriault-Proulx (2), Rocco Flores (3), Stephanie Smith (3), Grant Koenig (3), Bas Raaymakers (1), Martin Fast (1) | 1. Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands, 2. Medscint, Québec, Quebec, Canada, 3. Modus QA, London, Ontario, Canada

Comparison Between the HYPERSCINT RP200 Scintillation Detector and Other Small Field Detectors for 10MV FFF SRS Beam Modelling On a VersaHD Linear Accelerator

1. Small-Field Dosimetry, 7. Commissioning, MV Photon, Angular dependancy, Beam characterization, Commissioning, Detector comparaison, Energy Dependency, Quality Assurance Show more

Plastic scintillation detectors (PSDs) have advantageous dosimetric properties, including small size and energy independence, which make them ideal candidates for small field dosimetry.

2021 AAPM ANNUAL MEETING
J.Morin, JF.Cabana, M.Goulet, D.Theriault | CISSS – Chaudiere-Appalaches, Lévis, QC, CA

Characterization of the HYPERSCINT Dosimetry System for Real-Time Dosimetry Measurements with the Varian TrueBeamLinac

7. Commissioning, MV Photon, Adaptive-RT, Quality Assurance, Real-time Dosimetry Show more

Plastic scintillator/optical fibre dosimetry systems are advantageous due to their near water equivalence, waterproof construction, linear dose response, and good spatial resolution due to their small size. The nanosecond decay times of plastic scintillators enable the possibility of real-time dosimetry. We tested the new HYPERSCINT fibre detector system to determine if, in addition to the expected dose and field size responses, this system can provide real-time dose information. The HYPERSCINT system is suitable after appropriate calibration to be used to measure relative dose delivered in cGy as well as indicate changing dose conditions within 0.3 seconds.

2020 AAPM AM
C.Penner (1,2), C.Hoehr (2), C.Mendez (1), C.Duzenli (1) | BC Cancer, Vancouver, BC, CA, TRIUMF, Vancouver, BC, CA

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