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

Development and first implementation of a novel multi-modality cardiac motion and dosimetry phantom for radiotherapy applications

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

Magnetic resonance guided radiation therapy (MRgRT) for real-time gating around the heart for treating ventricular tachycardia (VT) are rapidly advancing. A novel, multi-modality modular heart phantom was developed and utilized in gated radiotherapy experiments on a 0.35 T MR-linac. This phantom can simulate cardiac, cardio-respiratory, and respiratory motions, and perform dosimetric evaluations using ionization chamber and plastic scintillation detectors (PSD from MEDSCINT) configurations.

Due to their small sensitive volumes, time-resolved PSDs are effective for low-amplitude/high-frequency movements and multi-point data acquisition, enhancing dosimetric capabilities. This advancement in VT planning and delivery illustrates the phantom’s potential to meet the growing demands of cardiac applications in radiotherapy.

MEDICAL PHYSICS
Kenneth W. Gregg (1,2), Chase Ruff (1,2), Grant Koenig (3), Kalin I. Penev (3), Andrew Shepard (1), Grace Kreissler (4), Margo Amatuzio (4), Cameron Owens (4), Prashant Nagpal (5), Carri K. Glide-Hurst (1,2) | 1. Department of Human Oncology, University of Wisconsin–Madison, Madison, Wisconsin, USA, 2. Department of Medical Physics, University of Wisconsin–Madison, Madison, Wisconsin, USA, 3. Modus Medical Devices, Inc. (IBA QUASAR),London, Ontario, Canada, 4. Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, Wisconsin, USA, 5. Department of Radiology, University of Wisconsin–Madison, Madison, Wisconsin, USA

MLC tracking and dose accumulation validation on the MR-linac using a real-time deformable dosimeter

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

Online MRI on the MR-linac captures detailed anatomical movements, improving real-time radiotherapy adaptations. However, the lack of a suitable MRI-compatible phantom hinders workflow validation. This study introduces a deformable phantom with integrated real-time scintillation dosimeters, validating accuracy in MLC tracking and dose accumulation using the ELEKTA Unity MR-linac.

This study demonstrates the vast potential of this novel prototype deformable phantom with integrated PSDs for real-time dosimetry measurements on an MR-linac.

2024 ESTRO Annual Congress
Madelon van den Dobbelsteen (1), Pim T.S. Borman (1), Laurie J.M. de Vries (1), Sara L. Hackett (1), Kalin Penev (1), Rocco Flores (2), Stephanie Smith (2), Yoan LeChasseur (3), Simon Lambert-Girard (3), Benjamin Côté (3) , Peter L. Woodhead (1)(4), Lando S. Bosma (1), Cornel Zachiu (1), Bas W. Raaymakers (1), Martin F. Fast (1) | 1 University Medical Center Utrecht, Radiotherapy, Utrecht, Netherlands., 2 IBA QUASAR, Modus Medical Devices Inc. London ON, Canada. , 3 Medscint, -, Quebec City, Canada. , 4 Elekta AB, -, Stockholm, Sweden.

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

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

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

Patient Specific QA for External Beam Radiotherapy Using the HYPERSCINT Plastic Scintillation Detector

3. Treatment Plan (End-to-End) QA, MV Photon, Detector comparaison, Phantom QA, Quality Assurance Show more

Plastic scintillation detectors have interesting dosimetric properties, including small size and energy independence. These advantages make them well suited for VMAT patient-specific QA, either alone or in conjunction with a detector matrix. This work aims to determine if the HYPERSCINT scintillation dosimetry research platform can replace the classic ion chamber in a clinical patient-specific QA workflow.

2020 AAPM AM
M.Goulet | CISSS – Chaudiere-Appalaches, Lévis, QC, CA

Small field dosimetry of a Varian TrueBeam High Definition MLC linear accelerator using theHyperscint RP200 scintillation detector.

1. Small-Field Dosimetry, 7. Commissioning, MeV Electron, MV Photon, Angular dependancy, Energy Dependency, Phantom QA, Quality Assurance Show more

Small field dosimetry of a Varian TrueBeam High Definition MLC linear accelerator using the Hyperscint RP200 scintillation detector.

Purpose: To evaluate the performance of the new Hyperscint RP200 plastic scintillator for small field measurements of a Varian TrueBeam linear accelerator in comparison with the current state-of-the-art methodology in the clinic.

Methods: Small field measurements were performed using different detectors: a diamond detector (microDiamond, PTW), a diode (Razor, IBA), a compact ion chamber (Razor, IBA), and a 1mm x 1mm
plastic scintillation detector (Hyperscint RP200, Medscint). Correction factors based on measured field sizes, following TRS483 recommendations, were applied to all measurements. Output factors of a
TrueBeam linear accelerator were measured for field sizes of 0.5 cm to 2 cm for jaws and MLC configurations for 6-MV, 6-MV FFF and 10-MV FFF photon beams. Output factors for different circular collimators (0.4 cm to 2 cm) were also obtained at 10-MV FFF. Scintillator measurements were compared to the small-field dosimetry methodology used clinically.

Results: No correction factors were necessary for the plastic scintillation detector measurements. Scintillator measurements were within 1.1% of the standard methodology for all the small field geometries studied. Average relative differences were (0.3±0.5)%, (0.7±0.3)%, and (0.2±0.2)% for the 6-MV, 6-MV FFF, and 10-MV FFF, respectively. Output factors of circular field sizes down to 0.4-cm diameter were obtained with an average relative difference of (0.1±0.4)%, including a maximum difference of 0.7% for the smallest field.

Conclusion: This new scintillation dosimetry research platform shows great promises for small field dosimetry. It has the potential to be used as part of a single-detector no-correction-factor methodology.

2021 COMP ASM
L.Gingras, B.Côté, F.Berthiaume, S.Lambert-Girard, D.Leblanc, L.Archambault, L.Beaulieu, F.Therriault-Proulx | CHU de Quebec – Universite Laval, QC, CA, Département de radio-oncologie et Axe Oncologie du CRCHU de Québec, QC, CA, MedScint, QC, CA