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Ashraf MR, Melemenidis S, Liu K, Grilj V, Jansen J, Velasquez B, Connell L, Schulz JB, Bailat C, Libed A, Manjappa R, Dutt S, Soto L, Lau B, Garza A, Larsen W, Skinner L, Yu AS, Surucu M, Graves EE, Maxim PG, Kry SF, Vozenin MC, Schüler E, Loo BW. Multi-Institutional Audit of FLASH and Conventional Dosimetry With a 3D Printed Anatomically Realistic Mouse Phantom. Int J Radiat Oncol Biol Phys 2024:S0360-3016(24)00433-4. [PMID: 38493902 DOI: 10.1016/j.ijrobp.2024.03.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 03/03/2024] [Accepted: 03/10/2024] [Indexed: 03/19/2024]
Abstract
PURPOSE We conducted a multi-institutional dosimetric audit between FLASH and conventional dose rate (CONV) electron irradiations by using an anatomically realistic 3-dimensional (3D) printed mouse phantom. METHODS AND MATERIALS A computed tomography (CT) scan of a live mouse was used to create a 3D model of bony anatomy, lungs, and soft tissue. A dual-nozzle 3D printer was used to print the mouse phantom using acrylonitrile butadiene styrene (∼1.02 g/cm3) and polylactic acid (∼1.24 g/cm3) simultaneously to simulate soft tissue and bone densities, respectively. The lungs were printed separately using lightweight polylactic acid (∼0.64 g/cm3). Hounsfield units (HU), densities, and print-to-print stability of the phantoms were assessed. Three institutions were each provided a phantom and each institution performed 2 replicates of irradiations at selected anatomic regions. The average dose difference between FLASH and CONV dose distributions and deviation from the prescribed dose were measured with radiochromic film. RESULTS Compared with the reference CT scan, CT scans of the phantom demonstrated mass density differences of 0.10 g/cm3 for bone, 0.12 g/cm3 for lung, and 0.03 g/cm3 for soft tissue regions. Differences in HU between phantoms were <10 HU for soft tissue and bone, with lung showing the most variation (54 HU), but with minimal effect on dose distribution (<0.5%). Mean differences between FLASH and CONV decreased from the first to the second replicate (4.3%-1.2%), and differences from the prescribed dose decreased for both CONV (3.6%-2.5%) and FLASH (6.4%-2.7%). Total dose accuracy suggests consistent pulse dose and pulse number, although these were not specifically assessed. Positioning variability was observed, likely due to the absence of robust positioning aids or image guidance. CONCLUSIONS This study marks the first dosimetric audit for FLASH using a nonhomogeneous phantom, challenging conventional calibration practices reliant on homogeneous phantoms. The comparison protocol offers a framework for credentialing multi-institutional studies in FLASH preclinical research to enhance reproducibility of biologic findings.
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Affiliation(s)
- M Ramish Ashraf
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Stavros Melemenidis
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Kevin Liu
- Department of Radiation Physics, Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Veljko Grilj
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Jeannette Jansen
- Radiation Oncology Laboratory, Department of Radiation Oncology, Lausanne, University Hospital and University of Lausanne, Switzerland
| | - Brett Velasquez
- Department of Radiation Physics, Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Luke Connell
- Department of Radiation Physics, Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Joseph B Schulz
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Aaron Libed
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Rakesh Manjappa
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Suparna Dutt
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Luis Soto
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Brianna Lau
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Aaron Garza
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - William Larsen
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Lawrie Skinner
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Amy S Yu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Murat Surucu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Edward E Graves
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California
| | - Peter G Maxim
- Department of Radiation Oncology, University of California, Irvine, California
| | - Stephen F Kry
- Department of Radiation Physics, Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas; Imaging and Radiation Oncology Core, MD Anderson Cancer Center, Houston, USA
| | - Marie-Catherine Vozenin
- Radiation Oncology Laboratory, Department of Radiation Oncology, Lausanne, University Hospital and University of Lausanne, Switzerland; Radiotherapy and Radiobiology Sector, Radiation Therapy Service, University Hospital of Geneva, Geneva, Switzerland.
| | - Emil Schüler
- Department of Radiation Physics, Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
| | - Billy W Loo
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California.
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Leavitt RJ, Almeida A, Grilj V, Montay-Gruel P, Godfroid C, Petit B, Bailat C, Limoli CL, Vozenin MC. Acute Hypoxia Does Not Alter Tumor Sensitivity to FLASH Radiation Therapy. Int J Radiat Oncol Biol Phys 2024:S0360-3016(24)00320-1. [PMID: 38387809 DOI: 10.1016/j.ijrobp.2024.02.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 01/10/2024] [Accepted: 02/08/2024] [Indexed: 02/24/2024]
Abstract
PURPOSE Tumor hypoxia is a major cause of treatment resistance, especially to radiation therapy at conventional dose rate (CONV), and we wanted to assess whether hypoxia does alter tumor sensitivity to FLASH. METHODS AND MATERIALS We engrafted several tumor types (glioblastoma [GBM], head and neck cancer, and lung adenocarcinoma) subcutaneously in mice to provide a reliable and rigorous way to modulate oxygen supply via vascular clamping or carbogen breathing. We irradiated tumors using a single 20-Gy fraction at either CONV or FLASH, measured oxygen tension, monitored tumor growth, and sampled tumors for bulk RNAseq and pimonidazole analysis. Next, we inhibited glycolysis with trametinib in GBM tumors to enhance FLASH efficacy. RESULTS Using various subcutaneous tumor models, and in contrast to CONV, FLASH retained antitumor efficacy under acute hypoxia. These findings show that in addition to normal tissue sparing, FLASH could overcome hypoxia-mediated tumor resistance. Follow-up molecular analysis using RNAseq profiling uncovered a FLASH-specific profile in human GBM that involved cell-cycle arrest, decreased ribosomal biogenesis, and a switch from oxidative phosphorylation to glycolysis. Glycolysis inhibition by trametinib enhanced FLASH efficacy in both normal and clamped conditions. CONCLUSIONS These data provide new and specific insights showing the efficacy of FLASH in a radiation-resistant context, proving an additional benefit of FLASH over CONV.
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Affiliation(s)
- Ron J Leavitt
- Radiation Oncology Laboratory, Department of Radiation Oncology, Lausanne, University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Aymeric Almeida
- Radiation Oncology Laboratory, Department of Radiation Oncology, Lausanne, University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Veljko Grilj
- Institute of Radiation Physics, University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Pierre Montay-Gruel
- Radiation Oncology Laboratory, Department of Radiation Oncology, Lausanne, University Hospital and University of Lausanne, Lausanne, Switzerland; Radiation Oncology Department, Iridium Netwerk, Wilrijk (Antwerp), Belgium; Antwerp Research in Radiation Oncology (AReRO), Center for Oncological Research (CORE), University of Antwerp, Antwerp, Belgium
| | - Céline Godfroid
- Radiation Oncology Laboratory, Department of Radiation Oncology, Lausanne, University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Benoit Petit
- Radiation Oncology Laboratory, Department of Radiation Oncology, Lausanne, University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Charles L Limoli
- Department of Radiation Oncology, University of California, Irvine, California
| | - Marie-Catherine Vozenin
- Radiation Oncology Laboratory, Department of Radiation Oncology, Lausanne, University Hospital and University of Lausanne, Lausanne, Switzerland.
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Oesterle R, Bailat C, Buhlmann D, Bochud F, Grilj V. Construction and dosimetric characterization of a motorized scanning-slit system for electron FLASH experiments. Med Phys 2024; 51:1396-1404. [PMID: 37439505 PMCID: PMC10787038 DOI: 10.1002/mp.16610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 06/18/2023] [Accepted: 06/21/2023] [Indexed: 07/14/2023] Open
Abstract
BACKGROUND Beam scanning is a useful technique for the treatment of large tumors when the primary beam size is limited, which is the case with radiation beams used in FLASH radiotherapy. PURPOSE To optimize beam scanning as a dose delivery method for FLASH radiotherapy, it is necessary to first understand the effects of beam scanning on the FLASH effect. To do so, biological FLASH experiments need to be done using defined beam parameters with beam scanning and compared to the situation without beam scanning. In this regard, we propose implementation of a simple slit scanning system with an electron FLASH beam to obtain a scanned radiation field that closely resembles a static field. METHODS A pulsed electron linear accelerator (linac) was used in combination with a scanning slit system in order to simulate a scanned electron beam. Three configurations that produced homogeneous lateral profiles and high enough doses per pulse for FLASH experiments were established. The optimal scanning parameters were found for each configuration by examining the flatness of the obtained lateral dose profiles. Using the optimal scanning parameters, the scanned FLASH beams were dosimetrically characterized and compared to non-scanned open field beam. RESULTS A final electron FLASH beam scanning configuration was found for a 1 mm wide slit at a distance of 350 mm from the linac and a 2 mm wide slit at distances of 350 and 490 mm from the linac. The lateral profiles for these final configurations were found to have a homogeneity that is comparable to the open field profiles. The percentage depth dose (PDD) values found for these final configurations closely matched (by a few percentage) the PDD of the open field beam. CONCLUSIONS Three electron FLASH beam scanning configurations achieved by the motorized slit system were found to produce radiation fields similar to a non-scanned open field electron beam. These final configurations can therefore be used in future biological FLASH experiments to compare to non-scanned beam experiments in order to optimize beam scanning as a technique permitting the treatment of larger tumors with FLASH radiotherapy.
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Affiliation(s)
- Roxane Oesterle
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland
| | - Damien Buhlmann
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland
| | - Francois Bochud
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland
| | - Veljko Grilj
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland
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Vozenin MC, Alaghband Y, Drayson OGG, Piaget F, Leavitt R, Allen BD, Doan NL, Rostomyan T, Stabilini A, Reggiani D, Hajdas W, Yukihara EG, Norbury JW, Bailat C, Desorgher L, Baulch JE, Limoli CL. More May Not be Better: Enhanced Spacecraft Shielding May Exacerbate Cognitive Decrements by Increasing Pion Exposures during Deep Space Exploration. Radiat Res 2024; 201:93-103. [PMID: 38171489 DOI: 10.1667/rade-23-00241.1.s1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 12/15/2023] [Indexed: 01/05/2024]
Abstract
The pervasiveness of deep space radiation remains a confounding factor for the transit of humans through our solar system. Spacecraft shielding both protects astronauts but also contributes to absorbed dose through galactic cosmic ray interactions that produce secondary particles. The resultant biological effects drop to a minimum for aluminum shielding around 20 g/cm2 but increase with additional shielding. The present work evaluates for the first time, the impact of secondary pions on central nervous system functionality. The fractional pion dose emanating from thicker shielded spacecraft regions could contribute up to 10% of the total absorbed radiation dose. New results from the Paul Scherrer Institute have revealed that low dose exposures to 150 MeV positive and negative pions, akin to a Mars mission, result in significant, long-lasting cognitive impairments. These surprising findings emphasize the need to carefully evaluate shielding configurations to optimize safe exposure limits for astronauts during deep space travel.
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Affiliation(s)
- Marie-Catherine Vozenin
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Yasaman Alaghband
- Department of Radiation Oncology, University of California, Irvine, California 92697-2695
| | - Olivia G G Drayson
- Department of Radiation Oncology, University of California, Irvine, California 92697-2695
| | - Filippo Piaget
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Ron Leavitt
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Barrett D Allen
- Department of Radiation Oncology, University of California, Irvine, California 92697-2695
| | - Ngoc-Lien Doan
- Department of Radiation Oncology, University of California, Irvine, California 92697-2695
| | | | | | | | | | | | | | - Claude Bailat
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Laurent Desorgher
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Janet E Baulch
- Department of Radiation Oncology, University of California, Irvine, California 92697-2695
| | - Charles L Limoli
- Department of Radiation Oncology, University of California, Irvine, California 92697-2695
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Almeida A, Togno M, Ballesteros-Zebadua P, Franco-Perez J, Geyer R, Schaefer R, Petit B, Grilj V, Meer D, Safai S, Lomax T, Weber DC, Bailat C, Psoroulas S, Vozenin MC. Dosimetric and biologic intercomparison between electron and proton FLASH beams. Radiother Oncol 2024; 190:109953. [PMID: 37839557 DOI: 10.1016/j.radonc.2023.109953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 10/07/2023] [Accepted: 10/11/2023] [Indexed: 10/17/2023]
Abstract
BACKGROUND AND PURPOSE The FLASH effect has been validated in different preclinical experiments with electrons (eFLASH) and protons (pFLASH) operating at an average dose rate above 40 Gy/s. However, no systematic intercomparison of the FLASH effect produced by eFLASHvs. pFLASH has yet been performed and constitutes the aim of the present study. MATERIALS AND METHODS The electron eRT6/Oriatron/CHUV/5.5 MeV and proton Gantry1/PSI/170 MeV were used to deliver conventional (0.1 Gy/s eCONV and pCONV) and FLASH (≥110 Gy/s eFLASH and pFLASH) dose rates. Protons were delivered in transmission. Dosimetric and biologic intercomparisons were performed using previously validated dosimetric approaches and experimental murine models. RESULTS The difference between the average absorbed dose measured at Gantry 1 with PSI reference dosimeters and with CHUV/IRA dosimeters was -1.9 % (0.1 Gy/s) and + 2.5 % (110 Gy/s). The neurocognitive capacity of eFLASH and pFLASH irradiated mice was indistinguishable from the control, while both eCONV and pCONV irradiated cohorts showed cognitive decrements. Complete tumor response was obtained after an ablative dose of 20 Gy delivered with the two beams at CONV and FLASH dose rates. Tumor rejection upon rechallenge indicates that anti-tumor immunity was activated independently of the beam-type and the dose-rate. CONCLUSION Despite major differences in the temporal microstructure of proton and electron beams, this study shows that dosimetric standards can be established. Normal brain protection and tumor control were produced by the two beams. More specifically, normal brain protection was achieved when a single dose of 10 Gy was delivered in 90 ms or less, suggesting that the most important physical parameter driving the FLASH sparing effect might be the mean dose rate. In addition, a systemic anti-tumor immunological memory response was observed in mice exposed to high ablative dose of electron and proton delivered at CONV and FLASH dose rate.
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Affiliation(s)
- A Almeida
- Laboratory of Radiation Oncology/Radiation Oncology Service/Department of Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - M Togno
- Center for Proton Therapy, Paul Scherrer Institute, 5323, Villigen, Switzerland
| | - P Ballesteros-Zebadua
- Laboratory of Radiation Oncology/Radiation Oncology Service/Department of Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland; Instituto Nacional de Neurología y Neurocirugía MVS, Mexico City, Mexico
| | - J Franco-Perez
- Laboratory of Radiation Oncology/Radiation Oncology Service/Department of Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland; Instituto Nacional de Neurología y Neurocirugía MVS, Mexico City, Mexico
| | - R Geyer
- Department of Radiation Oncology, lnselspital, Bern University Hospital, University of Bern, Switzerland
| | - R Schaefer
- Center for Proton Therapy, Paul Scherrer Institute, 5323, Villigen, Switzerland
| | - B Petit
- Laboratory of Radiation Oncology/Radiation Oncology Service/Department of Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - V Grilj
- Institute of Radiation Physics (IRA)/CHUV, Lausanne University Hospital, Lausanne, Switzerland
| | - D Meer
- Center for Proton Therapy, Paul Scherrer Institute, 5323, Villigen, Switzerland
| | - S Safai
- Center for Proton Therapy, Paul Scherrer Institute, 5323, Villigen, Switzerland
| | - T Lomax
- Center for Proton Therapy, Paul Scherrer Institute, 5323, Villigen, Switzerland
| | - D C Weber
- Center for Proton Therapy, Paul Scherrer Institute, 5323, Villigen, Switzerland; Department of Radiation Oncology, lnselspital, Bern University Hospital, University of Bern, Switzerland; Department of Radiation Oncology, University Hospital of Zurich, Switzerland
| | - C Bailat
- Institute of Radiation Physics (IRA)/CHUV, Lausanne University Hospital, Lausanne, Switzerland
| | - S Psoroulas
- Center for Proton Therapy, Paul Scherrer Institute, 5323, Villigen, Switzerland
| | - Marie-Catherine Vozenin
- Laboratory of Radiation Oncology/Radiation Oncology Service/Department of Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland; Radiotherapy and Radiobiology sector, Radiation Therapy service, University hospital of Geneva, Geneva, Switzerland.
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Juget F, van Dijk M, Maugeri EA, Schumann MD, Heinitz S, Boyarsky A, Köster U, Shchutska L, Bailat C. Measurement of the 171Tm beta spectrum. Appl Radiat Isot 2023; 202:111058. [PMID: 37797449 DOI: 10.1016/j.apradiso.2023.111058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 09/24/2023] [Accepted: 09/26/2023] [Indexed: 10/07/2023]
Abstract
The beta spectrum of the main transition of the β- decay of 171Tm was measured using a double focalizing spectrometer. The instrument was lately improved in order to reduce its low energy threshold to 34 keV. We used the spectrometer to measure the beta spectrum end-point energy of the main transition of 171Tm decay using the Kurie plot formalism. We report a new value of 97.60(38) keV, which is in agreement with previous measurements. In addition, the spectrum shape was compared with the ξ-approximation calculation where the shape factor is equal to 1 and good agreement was found between the theory and the measurement at the 1% level.
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Affiliation(s)
| | - Maarten van Dijk
- Laboratoire de Physique des Hautes Energies, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | | | | | | | - Alexey Boyarsky
- Laboratoire de Physique des Hautes Energies, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; Instituut Lorentz, Leiden University, Leiden, the Netherlands
| | | | - Lesya Shchutska
- Laboratoire de Physique des Hautes Energies, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne, Switzerland
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Nedjadi Y, Durán MT, Juget F, Bochud F, Veicht M, Schumann D, Mihalcea I, Kossert K, Bailat C. Activity standardisation of 32Si at IRA-METAS. Appl Radiat Isot 2023; 202:111041. [PMID: 37776633 DOI: 10.1016/j.apradiso.2023.111041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 09/22/2023] [Accepted: 09/22/2023] [Indexed: 10/02/2023]
Abstract
This work explores the primary activity standardisation of 32Si as part of the SINCHRON project that aims at filling the geochronological dating gap by making a new precise measurement of the half-life of this nuclide. The stability of some of the radioactive test solutions, providing 32Si as hexafluorosilicic acid (H232SiF6), was monitored over long periods, pointing to the adequate sample composition and vial type to ensure stability. These solutions were standardised using liquid scintillation counting with the triple to double coincidence ratio (TDCR) technique and the CIEMAT-NIST efficiency tracing (CNET) method. Complementary backup measurements, using 4πβ-γ coincidence counting with 60Co as a tracer, were performed with both liquid and plastic scintillation for beta detection. While 60Co coincidence tracing with a liquid scintillator predicted activities in agreement with the TDCR and CNET determinations, using plastic scintillation turned out to be unfeasible as the addition of lanthanum nitrate and ammonia to fix the silicon during the drying process generated large crystals that compromised the linearity of the efficiency function.
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Affiliation(s)
| | | | | | | | - Mario Veicht
- Laboratory of Radiochemistry, Paul Scherrer Institut, Villigen-PSI, Switzerland
| | - Dorothea Schumann
- Laboratory of Radiochemistry, Paul Scherrer Institut, Villigen-PSI, Switzerland
| | - Ionut Mihalcea
- Laboratory of Radiochemistry, Paul Scherrer Institut, Villigen-PSI, Switzerland
| | - Karsten Kossert
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
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Böhlen TT, Germond JF, Petersson K, Ozsahin EM, Herrera FG, Bailat C, Bochud F, Bourhis J, Moeckli R, Adrian G. Effect of Conventional and Ultrahigh Dose Rate FLASH Irradiations on Preclinical Tumor Models: A Systematic Analysis. Int J Radiat Oncol Biol Phys 2023; 117:1007-1017. [PMID: 37276928 DOI: 10.1016/j.ijrobp.2023.05.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 04/19/2023] [Accepted: 05/26/2023] [Indexed: 06/07/2023]
Abstract
PURPOSE Compared with conventional dose rate irradiation (CONV), ultrahigh dose rate irradiation (UHDR) has shown superior normal tissue sparing. However, a clinically relevant widening of the therapeutic window by UHDR, termed "FLASH effect," also depends on the tumor toxicity obtained by UHDR. Based on a combined analysis of published literature, the current study examined the hypothesis of tumor isoefficacy for UHDR versus CONV and aimed to identify potential knowledge gaps to inspire future in vivo studies. METHODS AND MATERIALS A systematic literature search identified publications assessing in vivo tumor responses comparing UHDR and CONV. Qualitative and quantitative analyses were performed, including combined analyses of tumor growth and survival data. RESULTS We identified 66 data sets from 15 publications that compared UHDR and CONV for tumor efficacy. The median number of animals per group was 9 (range 3-15) and the median follow-up period was 30.5 days (range 11-230) after the first irradiation. Tumor growth assays were the predominant model used. Combined statistical analyses of tumor growth and survival data are consistent with UHDR isoefficacy compared with CONV. Only 1 study determined tumor-controlling dose (TCD50) and reported statistically nonsignificant differences. CONCLUSIONS The combined quantitative analyses of tumor responses support the assumption of UHDR isoefficacy compared with CONV. However, the comparisons are primarily based on heterogeneous tumor growth assays with limited numbers of animals and short follow-up, and most studies do not assess long-term tumor control probability. Therefore, the assays may be insensitive in resolving smaller response differences, such as responses of radioresistant tumor subclones. Hence, tumor cure experiments, including additional TCD50 experiments, are needed to confirm the assumption of isoeffectiveness in curative settings.
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Affiliation(s)
- Till Tobias Böhlen
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Jean-François Germond
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Kristoffer Petersson
- Department of Hematology, Oncology, and Radiation Physics, Skåne University Hospital, Lund, Sweden; MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Esat Mahmut Ozsahin
- Department of Radiation Oncology, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Fernanda G Herrera
- Department of Radiation Oncology, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - François Bochud
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Jean Bourhis
- Department of Radiation Oncology, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Raphaël Moeckli
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland.
| | - Gabriel Adrian
- Department of Hematology, Oncology, and Radiation Physics, Skåne University Hospital, Lund, Sweden; Division of Oncology and Pathology, Department of Clinical Sciences, Skåne University Hospital, Lund University, Lund, Sweden
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9
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Juget F, Talip Z, Buchillier T, Durán MT, Nedjadi Y, Desorgher L, Bochud F, Grundler P, van der Meulen NP, Bailat C. Corrigendum to "Determination of the gamma and X-ray emission intensities of terbium-161" [Appl. Radiat. Isot. 174 (2021) 109770]. Appl Radiat Isot 2023; 200:110955. [PMID: 37516578 DOI: 10.1016/j.apradiso.2023.110955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/31/2023]
Affiliation(s)
| | - Zeynep Talip
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland
| | | | | | | | | | | | - Pascal Grundler
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland
| | - Nicholas P van der Meulen
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland; Laboratory of Radiochemistry, Paul Scherrer Institute, Villigen-PSI, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne, Switzerland
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Desorgher L, Stabilini A, Rostomyan T, Reggiani D, Hajdas W, Marcinkowski RM, Vozenin MC, Limoli CL, Yukihara EG, Bailat C. Dosimetry of the PIM1 Pion Beam at the Paul Scherrer Institute for Radiobiological Studies of Mice. Radiat Res 2023; 200:357-365. [PMID: 37702413 DOI: 10.1667/rade-23-00029.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 07/31/2023] [Indexed: 09/14/2023]
Abstract
Significant past work has identified unexpected risks of central nervous system (CNS) exposure to the space radiation environment, where long-lasting functional decrements have been associated with multiple ion species delivered at low doses and dose rates. As shielding is the only established intervention capable of limiting exposure to the dangerous radiation fields in space, the recent discovery that pions, emanating from regions of enhanced shielding, can contribute significantly to the total absorbed dose on a deep space mission poses additional concerns. As a prerequisite to biological studies evaluating pion dose equivalents for various CNS exposure scenarios of mice, a careful dosimetric validation study is required. Within our ultimate goal of evaluating the functional consequences of defined pion exposures to CNS functionality, we report in this article the detailed dosimetry of the PiMI pion beam line at the Paul Scherrer Institute, which was developed in support of radiobiological experiments. Beam profiles and contamination of the beam by protons, electrons, positrons and muons were characterized prior to the mice irradiations. The dose to the back and top of the mice was measured using thermoluminescent dosimeters (TLD) and optically simulated luminescence (OSL) to cross-validate the dosimetry results. Geant4 Monte Carlo simulations of radiation exposure of a mouse phantom in water by charged pions were also performed to quantify the difference between the absorbed dose from the OSL and TLD and the absorbed dose to water, using a simple model of the mouse brain. The absorbed dose measured by the OSL dosimeters and TLDs agreed within 5-10%. A 30% difference between the measured absorbed dose and the dose calculated by Geant4 in the dosimeters was obtained, probably due to the approximated Monte Carlo configuration compared to the experiment. A difference of 15-20% between the calculated absorbed dose to water at a 5 mm depth and in the passive dosimeters was obtained, suggesting the need for a correction factor of the measured dose to obtain the absorbed dose in the mouse brain. Finally, based on the comparison of the experimental data and the Monte Carlo calculations, we consider the dose measurement to be accurate to within 15-20%.
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Affiliation(s)
- L Desorgher
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Switzerland
| | - A Stabilini
- Paul Scherrer Institute (PSI), Villigen, Switzerland
| | - T Rostomyan
- Paul Scherrer Institute (PSI), Villigen, Switzerland
| | - D Reggiani
- Paul Scherrer Institute (PSI), Villigen, Switzerland
| | - W Hajdas
- Paul Scherrer Institute (PSI), Villigen, Switzerland
| | - R M Marcinkowski
- Paul Scherrer Institute (PSI), Villigen, Switzerland
- SE2S GMBH, Boppelsen ZH, Switzerland
| | - M-C Vozenin
- CHUV-Radiation-oncology Laboratory, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - C L Limoli
- Department of Radiation Oncology, University of California, Irvine, California
| | - E G Yukihara
- Paul Scherrer Institute (PSI), Villigen, Switzerland
| | - C Bailat
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Switzerland
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11
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Nedjadi Y, Juget F, Durán MT, Desorgher L, Bochud F, Bailat C. Activity standardisation of 177Lu. Appl Radiat Isot 2023; 200:110986. [PMID: 37597267 DOI: 10.1016/j.apradiso.2023.110986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 08/08/2023] [Accepted: 08/14/2023] [Indexed: 08/21/2023]
Abstract
177Lu decays through low-energy β-- and γ-emissions in addition to conversion and Auger electrons. To support the use of this radiopharmaceutical in Switzerland, a 177Lu solution was standardised using the β-γ coincidence technique, as well as the TDCR method. The solution had no 177mLu impurity. Primary coincidence measurements, with plastic scintillators for beta detection, were carried out using both analogue and digital electronics. TDCR measurements using only defocusing were also made. Monte Carlo calculations were used to compute the detection efficiency. The coincidence measurements with both analogue and digital electronics are compatible within one standard uncertainty, but they are lower than (and discrepant with) the TDCR measurements. An ampoule of this solution was submitted to the BIPM as a contribution to the Système International de Référence.
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12
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Ashraf MR, Melemenidis S, Liu K, Grilj V, Jansen J, Velasquez B, Connell L, Schulz JB, Bailat C, Libed A, Manjappa R, Dutt S, Soto L, Lau B, Garza A, Larsen W, Skinner L, Yu AS, Surucu M, Graves EE, Maxim PG, Kry SF, Vozenin MC, Schüler E, Jr BWL. Multi-Institutional Audit of FLASH and Conventional Dosimetry with a 3D-Printed Anatomically Realistic Mouse Phantom. ArXiv 2023:arXiv:2309.16836v1. [PMID: 37808098 PMCID: PMC10557797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
We conducted a multi-institutional audit of dosimetric variability between FLASH and conventional dose rate (CONV) electron irradiations by using an anatomically realistic 3D-printed mouse phantom. A CT scan of a live mouse was used to create a 3D model of bony anatomy, lungs, and soft tissue. A dual-nozzle 3D printer was used to print the mouse phantom using acrylonitrile butadiene styrene ($~1.02 g/cm^3$) and polylactic acid ($~1.24 g/cm^3$) simultaneously to simulate soft tissue and bone densities, respectively. The lungs were printed separately using lightweight polylactic acid ($~0.64 g/cm^3$). Hounsfield units (HU) and densities were compared with the reference CT scan of the live mouse. Print-to-print reproducibility of the phantom was assessed. Three institutions were each provided a phantom, and each institution performed two replicates of irradiations at selected mouse anatomic regions. The average dose difference between FLASH and CONV dose distributions and deviation from the prescribed dose were measured with radiochromic film. Compared to the reference CT scan, CT scans of the phantom demonstrated mass density differences of $0.10 g/cm^3$ for bone, $0.12 g/cm^3$ for lung, and $0.03 g/cm^3$ for soft tissue regions. Between phantoms, the difference in HU for soft tissue and bone was <10 HU from print to print. Lung exhibited the most variation (54 HU) but minimally affected dose distribution (<0.5% dose differences between phantoms). The mean difference between FLASH and CONV from the first replicate to the second decreased from 4.3% to 1.2%, and the mean difference from the prescribed dose decreased from 3.6% to 2.5% for CONV and 6.4% to 2.7% for FLASH. The framework presented here is promising for credentialing of multi-institutional studies of FLASH preclinical research to maximize the reproducibility of biological findings.
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Chappuis F, Tran HN, Zein SA, Bailat C, Incerti S, Bochud F, Desorgher L. The general-purpose Geant4 Monte Carlo toolkit and its Geant4-DNA extension to investigate mechanisms underlying the FLASH effect in radiotherapy: Current status and challenges. Phys Med 2023; 110:102601. [PMID: 37201453 DOI: 10.1016/j.ejmp.2023.102601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/06/2023] [Accepted: 05/01/2023] [Indexed: 05/20/2023] Open
Abstract
FLASH radiotherapy is a promising approach to cancer treatment that offers several advantages over conventional radiotherapy. With this novel technique, high doses of radiation are delivered in a short period of time, inducing the so-called FLASH effect - a phenomenon characterized by healthy tissue sparing without alteration of tumor control. The mechanisms behind the FLASH effect remain unknown. One way to approach this problem is to gain insight into the initial parameters that can distinguish FLASH from conventional irradiation by simulating particle transport in aqueous media using the general-purpose Geant4 Monte Carlo toolkit and its Geant4-DNA extension. This review article discusses the current status of Geant4 and Geant4-DNA simulations to investigate mechanisms underlying the FLASH effect, as well as the challenges faced in this research field. One of the primary challenges is to accurately simulate the experimental irradiation parameters. Another challenge is the temporal extension of the simulations. This review also focuses on two hypotheses to explain the FLASH effect - namely the oxygen depletion hypothesis and the inter-track interactions hypothesis - and discusses how the Geant4 toolkit can be used to investigate them. The aim of this review is to provide an overview of Geant4 and Geant4-DNA simulations for FLASH radiotherapy and to highlight the challenges that need to be overcome in order to better study the FLASH effect.
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Affiliation(s)
- Flore Chappuis
- Institute of Radiation Physics (IRA), Lausanne University Hospital and University of Lausanne, CH-1007 Lausanne, Switzerland
| | - Hoang Ngoc Tran
- Univ. Bordeaux, CNRS, LP2I Bordeaux, UMR 5797, F-33170 Gradignan, France
| | - Sara A Zein
- Univ. Bordeaux, CNRS, LP2I Bordeaux, UMR 5797, F-33170 Gradignan, France
| | - Claude Bailat
- Institute of Radiation Physics (IRA), Lausanne University Hospital and University of Lausanne, CH-1007 Lausanne, Switzerland
| | - Sébastien Incerti
- Univ. Bordeaux, CNRS, LP2I Bordeaux, UMR 5797, F-33170 Gradignan, France
| | - François Bochud
- Institute of Radiation Physics (IRA), Lausanne University Hospital and University of Lausanne, CH-1007 Lausanne, Switzerland
| | - Laurent Desorgher
- Institute of Radiation Physics (IRA), Lausanne University Hospital and University of Lausanne, CH-1007 Lausanne, Switzerland.
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14
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Allen BD, Alaghband Y, Kramár EA, Ru N, Petit B, Grilj V, Petronek MS, Pulliam CF, Kim RY, Doan NL, Baulch JE, Wood MA, Bailat C, Spitz DR, Vozenin MC, Limoli CL. Elucidating the neurological mechanism of the FLASH effect in juvenile mice exposed to hypofractionated radiotherapy. Neuro Oncol 2023; 25:927-939. [PMID: 36334265 PMCID: PMC10158064 DOI: 10.1093/neuonc/noac248] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Ultrahigh dose-rate radiotherapy (FLASH-RT) affords improvements in the therapeutic index by minimizing normal tissue toxicities without compromising antitumor efficacy compared to conventional dose-rate radiotherapy (CONV-RT). To investigate the translational potential of FLASH-RT to a human pediatric medulloblastoma brain tumor, we used a radiosensitive juvenile mouse model to assess adverse long-term neurological outcomes. METHODS Cohorts of 3-week-old male and female C57Bl/6 mice exposed to hypofractionated (2 × 10 Gy, FLASH-RT or CONV-RT) whole brain irradiation and unirradiated controls underwent behavioral testing to ascertain cognitive status four months posttreatment. Animals were sacrificed 6 months post-irradiation and tissues were analyzed for neurological and cerebrovascular decrements. RESULTS The neurological impact of FLASH-RT was analyzed over a 6-month follow-up. FLASH-RT ameliorated neurocognitive decrements induced by CONV-RT and preserved synaptic plasticity and integrity at the electrophysiological (long-term potentiation), molecular (synaptophysin), and structural (Bassoon/Homer-1 bouton) levels in multiple brain regions. The benefits of FLASH-RT were also linked to reduced neuroinflammation (activated microglia) and the preservation of the cerebrovascular structure, by maintaining aquaporin-4 levels and minimizing microglia colocalized to vessels. CONCLUSIONS Hypofractionated FLASH-RT affords significant and long-term normal tissue protection in the radiosensitive juvenile mouse brain when compared to CONV-RT. The capability of FLASH-RT to preserve critical cognitive outcomes and electrophysiological properties over 6-months is noteworthy and highlights its potential for resolving long-standing complications faced by pediatric brain tumor survivors. While care must be exercised before clinical translation is realized, present findings document the marked benefits of FLASH-RT that extend from synapse to cognition and the microvasculature.
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Affiliation(s)
- Barrett D Allen
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Yasaman Alaghband
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Eniko A Kramár
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA
| | - Ning Ru
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Benoit Petit
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Veljko Grilj
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Michael S Petronek
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, University of Iowa, Iowa City, IA 52242, USA
| | - Casey F Pulliam
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, University of Iowa, Iowa City, IA 52242, USA
| | - Rachel Y Kim
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Ngoc-Lien Doan
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Janet E Baulch
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
| | - Marcelo A Wood
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA
| | - Claude Bailat
- Institute of Radiation Physics/CHUV, Lausanne University Hospital, Lausanne, Switzerland
| | - Douglas R Spitz
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, University of Iowa, Iowa City, IA 52242, USA
| | - Marie-Catherine Vozenin
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Charles L Limoli
- Department of Radiation Oncology, University of California, Irvine, CA 92697-2695, USA
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15
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Almeida A, Togno M, Ballesteros-Zebadua P, Franco-Perez J, Geyer R, Schaefer R, Petit B, Grilj V, Meer D, Safai S, Lomax T, Weber DC, Bailat C, Psoroulas S, Vozenin MC. Dosimetric and biologic intercomparison between electron and proton FLASH beams. bioRxiv 2023:2023.04.20.537497. [PMID: 37131769 PMCID: PMC10153243 DOI: 10.1101/2023.04.20.537497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Background and purpose The FLASH effect has been validated in different preclinical experiments with electrons (eFLASH) and protons (pFLASH) operating at a mean dose rate above 40 Gy/s. However, no systematic intercomparison of the FLASH effect produced by e vs. pFLASH has yet been performed and constitutes the aim of the present study. Materials and methods The electron eRT6/Oriatron/CHUV/5.5 MeV and proton Gantry1/PSI/170 MeV were used to deliver conventional (0.1 Gy/s eCONV and pCONV) and FLASH (≥100 Gy/s eFLASH and pFLASH) irradiation. Protons were delivered in transmission. Dosimetric and biologic intercomparisons were performed with previously validated models. Results Doses measured at Gantry1 were in agreement (± 2.5%) with reference dosimeters calibrated at CHUV/IRA. The neurocognitive capacity of e and pFLASH irradiated mice was indistinguishable from the control while both e and pCONV irradiated cohorts showed cognitive decrements. Complete tumor response was obtained with the two beams and was similar between e and pFLASH vs. e and pCONV. Tumor rejection was similar indicating that T-cell memory response is beam-type and dose-rate independent. Conclusion Despite major differences in the temporal microstructure, this study shows that dosimetric standards can be established. The sparing of brain function and tumor control produced by the two beams were similar, suggesting that the most important physical parameter driving the FLASH effect is the overall time of exposure which should be in the range of hundreds of milliseconds for WBI in mice. In addition, we observed that immunological memory response is similar between electron and proton beams and is independent off the dose rate.
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Affiliation(s)
- A Almeida
- Laboratory of Radiation Oncology/Radiation Oncology Service/Department of Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - M Togno
- Center for Proton Therapy, Paul Scherrer Institute, 5323 Villigen PSI, Switzerland
| | - P Ballesteros-Zebadua
- Laboratory of Radiation Oncology/Radiation Oncology Service/Department of Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- Instituto Nacional de Neurología y Neurocirugía MVS, Mexico City, Mexico
| | - J Franco-Perez
- Laboratory of Radiation Oncology/Radiation Oncology Service/Department of Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- Instituto Nacional de Neurología y Neurocirugía MVS, Mexico City, Mexico
| | - R Geyer
- Department of Radiation Oncology, lnselspital, Bern University Hospital, University of Bern, Switzerland
| | - R Schaefer
- Center for Proton Therapy, Paul Scherrer Institute, 5323 Villigen PSI, Switzerland
| | - B Petit
- Laboratory of Radiation Oncology/Radiation Oncology Service/Department of Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - V Grilj
- Institute of Radiation Physics (IRA)/CHUV, Lausanne University Hospital, Lausanne, Switzerland
| | - D Meer
- Center for Proton Therapy, Paul Scherrer Institute, 5323 Villigen PSI, Switzerland
| | - S Safai
- Center for Proton Therapy, Paul Scherrer Institute, 5323 Villigen PSI, Switzerland
| | - T Lomax
- Center for Proton Therapy, Paul Scherrer Institute, 5323 Villigen PSI, Switzerland
| | - D C Weber
- Center for Proton Therapy, Paul Scherrer Institute, 5323 Villigen PSI, Switzerland
- Department of Radiation Oncology, lnselspital, Bern University Hospital, University of Bern, Switzerland
- Department of Radiation Oncology, University Hospital of Zurich, Switzerland
| | - C Bailat
- Institute of Radiation Physics (IRA)/CHUV, Lausanne University Hospital, Lausanne, Switzerland
| | - S Psoroulas
- Center for Proton Therapy, Paul Scherrer Institute, 5323 Villigen PSI, Switzerland
| | - M C Vozenin
- Laboratory of Radiation Oncology/Radiation Oncology Service/Department of Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
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Valdés Zayas A, Kumari N, Liu K, Neill D, Delahoussaye A, Gonçalves Jorge P, Geyer R, Lin SH, Bailat C, Bochud F, Moeckli R, Koong AC, Bourhis J, Taniguchi CM, Herrera FG, Schüler E. Independent Reproduction of the FLASH Effect on the Gastrointestinal Tract: A Multi-Institutional Comparative Study. Cancers (Basel) 2023; 15:cancers15072121. [PMID: 37046782 PMCID: PMC10093322 DOI: 10.3390/cancers15072121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 03/27/2023] [Accepted: 03/31/2023] [Indexed: 04/05/2023] Open
Abstract
FLASH radiation therapy (RT) is a promising new paradigm in radiation oncology. However, a major question that remains is the robustness and reproducibility of the FLASH effect when different irradiators are used on animals or patients with different genetic backgrounds, diets, and microbiomes, all of which can influence the effects of radiation on normal tissues. To address questions of rigor and reproducibility across different centers, we analyzed independent data sets from The University of Texas MD Anderson Cancer Center and from Lausanne University (CHUV). Both centers investigated acute effects after total abdominal irradiation to C57BL/6 animals delivered by the FLASH Mobetron system. The two centers used similar beam parameters but otherwise conducted the studies independently. The FLASH-enabled animal survival and intestinal crypt regeneration after irradiation were comparable between the two centers. These findings, together with previously published data using a converted linear accelerator, show that a robust and reproducible FLASH effect can be induced as long as the same set of irradiation parameters are used.
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Affiliation(s)
- Anet Valdés Zayas
- Radio-Oncology Department, AGORA Cancer Research Institute, Lausanne University Hospital, Lausanne University, Rue du Bugnon 46, CH-1011 Lausanne, Switzerland
| | - Neeraj Kumari
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Kevin Liu
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Graduate School of Biomedical Sciences, The University of Texas, Houston, TX 77030, USA
| | - Denae Neill
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Abagail Delahoussaye
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Patrik Gonçalves Jorge
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne University, Rue du Grand-Pré-1, CH-1007 Lausanne, Switzerland
| | - Reiner Geyer
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne University, Rue du Grand-Pré-1, CH-1007 Lausanne, Switzerland
| | - Steven H. Lin
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Graduate School of Biomedical Sciences, The University of Texas, Houston, TX 77030, USA
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne University, Rue du Grand-Pré-1, CH-1007 Lausanne, Switzerland
| | - François Bochud
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne University, Rue du Grand-Pré-1, CH-1007 Lausanne, Switzerland
| | - Raphael Moeckli
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne University, Rue du Grand-Pré-1, CH-1007 Lausanne, Switzerland
| | - Albert C. Koong
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Graduate School of Biomedical Sciences, The University of Texas, Houston, TX 77030, USA
| | - Jean Bourhis
- Radio-Oncology Department, AGORA Cancer Research Institute, Lausanne University Hospital, Lausanne University, Rue du Bugnon 46, CH-1011 Lausanne, Switzerland
| | - Cullen M. Taniguchi
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Graduate School of Biomedical Sciences, The University of Texas, Houston, TX 77030, USA
| | - Fernanda G. Herrera
- Radio-Oncology Department, AGORA Cancer Research Institute, Lausanne University Hospital, Lausanne University, Rue du Bugnon 46, CH-1011 Lausanne, Switzerland
| | - Emil Schüler
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Graduate School of Biomedical Sciences, The University of Texas, Houston, TX 77030, USA
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Froidevaux P, Grilj V, Bailat C, Geyer WR, Bochud F, Vozenin MC. FLASH irradiation does not induce lipid peroxidation in lipids micelles and liposomes. Radiat Phys Chem Oxf Engl 1993 2023. [DOI: 10.1016/j.radphyschem.2022.110733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Böhlen TT, Germond JF, Bochud F, Bailat C, Moeckli R, Bourhis J, Vozenin MC, Ozsahin EM. In Reply to Horst et al. Int J Radiat Oncol Biol Phys 2023; 115:1007-1009. [PMID: 36822773 DOI: 10.1016/j.ijrobp.2022.11.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 11/06/2022] [Indexed: 02/24/2023]
Affiliation(s)
- Till Tobias Böhlen
- ****Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Jean-François Germond
- ****Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - François Bochud
- ****Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Claude Bailat
- ****Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Raphaël Moeckli
- ****Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland.
| | - Jean Bourhis
- **Department of Radiation Oncology, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Marie-Catherine Vozenin
- **Department of Radiation Oncology, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Esat Mahmut Ozsahin
- **Department of Radiation Oncology, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
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Chappuis F, Grilj V, Tran HN, Zein SA, Bochud F, Bailat C, Incerti S, Desorgher L. Modeling of scavenging systems in water radiolysis with Geant4-DNA. Phys Med 2023; 108:102549. [PMID: 36921424 DOI: 10.1016/j.ejmp.2023.102549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 01/11/2023] [Accepted: 02/13/2023] [Indexed: 03/16/2023] Open
Abstract
PURPOSE This paper presents the capabilities of the Geant4-DNA Monte Carlo toolkit to simulate water radiolysis with scavengers using the step-by-step (SBS) or the independent reaction times (IRT) methods. It features two examples of application areas: (1) computing the escape yield of H2O2 following a 60Co γ-irradiation and (2) computing the oxygen depletion in water irradiated with 1 MeV electrons. METHODS To ease the implementation of the chemical stage in Geant4-DNA, we developed a user interface that helps define the chemical reactions and set the concentration of scavengers. The first application area example required two computational steps to perform water radiolysis using NO2- and NO3- as scavengers and a 60Co irradiation. The oxygen depletion computation technique for the second application area example consisted of simulating track segments of 1 MeV electrons and determining the radio-induced loss and gain of oxygen molecules. RESULTS The production of H2O2 under variable scavenging levels is consistent with the literature; the mean relative difference between the SBS and IRT methods is 7.2 % ± 0.5 %. For the oxygen depletion 1 µs post-irradiation, the mean relative difference between both methods is equal to 9.8 % ± 0.3 %. The results in the microsecond scale depend on the initial partial pressure of oxygen in water. In addition, the computed oxygen depletions agree well with the literature. CONCLUSIONS The Geant4-DNA toolkit makes it possible to simulate water radiolysis in the presence of scavengers. This feature offers perspectives in radiobiology, with the possibility of simulating cell-relevant scavenging mechanisms.
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Affiliation(s)
- Flore Chappuis
- Institute of Radiation Physics (IRA), Lausanne University Hospital and University of Lausanne, CH-1007 Lausanne, Switzerland
| | - Veljko Grilj
- Institute of Radiation Physics (IRA), Lausanne University Hospital and University of Lausanne, CH-1007 Lausanne, Switzerland
| | - Hoang Ngoc Tran
- Univ. Bordeaux, CNRS, LP2I Bordeaux, UMR 5797, F-33170 Gradignan, France
| | - Sara A Zein
- Univ. Bordeaux, CNRS, LP2I Bordeaux, UMR 5797, F-33170 Gradignan, France
| | - François Bochud
- Institute of Radiation Physics (IRA), Lausanne University Hospital and University of Lausanne, CH-1007 Lausanne, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics (IRA), Lausanne University Hospital and University of Lausanne, CH-1007 Lausanne, Switzerland
| | - Sébastien Incerti
- Univ. Bordeaux, CNRS, LP2I Bordeaux, UMR 5797, F-33170 Gradignan, France
| | - Laurent Desorgher
- Institute of Radiation Physics (IRA), Lausanne University Hospital and University of Lausanne, CH-1007 Lausanne, Switzerland.
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Böhlen TT, Germond JF, Bourhis J, Bailat C, Bochud F, Moeckli R. The minimal FLASH sparing effect needed to compensate the increase of radiobiological damage due to hypofractionation for late-reacting tissues. Med Phys 2022; 49:7672-7682. [PMID: 35933554 PMCID: PMC10087769 DOI: 10.1002/mp.15911] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 07/06/2022] [Accepted: 07/28/2022] [Indexed: 12/27/2022] Open
Abstract
PURPOSE Normal tissue (NT) sparing by ultra-high dose rate (UHDR) irradiations compared to conventional dose rate (CONV) irradiations while being isotoxic to the tumor has been termed "FLASH effect" and has been observed when large doses per fraction (d ≳ 5 Gy) have been delivered. Since hypofractionated treatment schedules are known to increase toxicities of late-reacting tissues compared to normofractionated schedules for many clinical scenarios at CONV dose rates, we developed a formalism based on the biologically effective dose (BED) to assess the minimum magnitude of the FLASH effect needed to compensate the loss of late-reacting NT sparing when reducing the number of fractions compared to a normofractionated CONV treatment schedule while remaining isoeffective to the tumor. METHODS By requiring the same BED for the tumor, we derived the "break-even NT sparing weighting factor" WBE for the linear-quadratic (LQ) and LQ-linear (LQ-L) models for an NT region irradiated at a relative dose r (relative to the prescribed dose per fraction d to the tumor). WBE was evaluated numerically for multiple values of d and r, and for different tumor and NT α/β-ratios. WBE was compared against currently available experimental data on the magnitude of the NT sparing provided by the FLASH effect for single fraction doses. RESULTS For many clinically relevant scenarios, WBE decreases steeply initially for d > 2 Gy for late-reacting tissues with (α/β)NT ≈ 3 Gy, implying that a significant NT sparing by the FLASH effect (between 15% and 30%) is required to counteract the increased radiobiological damage experienced by late-reacting NT for hypofractionated treatments with d < 10 Gy compared to normofractionated treatments that are equieffective to the tumor. When using the LQ model with generic α/β-ratios for tumor and late-reacting NT of (α/β)T = 10 Gy and (α/β)NT = 3 Gy, respectively, most currently available experimental evidence about the magnitude of NT sparing by the FLASH effect suggests no net NT sparing benefit for hypofractionated FLASH radiotherapy (RT) in the high-dose region when compared with WBE . Instead, clinical indications with more similar α/β-ratios of the tumor and dose-limiting NT toxicities [i.e., (α/β)T ≈ (α/β)NT ], such as prostate treatments, are generally less penalized by hypofractionated treatments and need consequently smaller magnitudes of NT sparing by the FLASH effect to achieve a net benefit. For strongly hypofractionated treatments (>10-15 Gy/fraction), the LQ-L model predicts, unlike the LQ model, a larger WBE suggesting a possible benefit of strongly hypofractionated FLASH RT, even for generic α/β-ratios of (α/β)T = 10 Gy and (α/β)NT = 3 Gy. However, knowledge on the isoeffect scaling for high doses per fraction (≳10 Gy/fraction) and its modeling is currently limited and impedes accurate and reliable predictions for such strongly hypofractionated treatments. CONCLUSIONS We developed a formalism that quantifies the minimal NT sparing by the FLASH effect needed to compensate for hypofractionation, based on the LQ and LQ-L models. For a given hypofractionated UHDR treatment scenario and magnitude of the FLASH effect, the formalism predicts if a net NT sparing benefit is expected compared to a respective normofractionated CONV treatment.
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Affiliation(s)
- Till Tobias Böhlen
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Jean-François Germond
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Jean Bourhis
- Department of Radiation Oncology, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - François Bochud
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Raphaël Moeckli
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
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21
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Jorge PG, Melemenidis S, Grilj V, Buchillier T, Manjappa R, Viswanathan V, Gondré M, Vozenin MC, Germond JF, Bochud F, Moeckli R, Limoli C, Skinner L, No HJ, Wu YF, Surucu M, Yu AS, Lau B, Wang J, Schüler E, Bush K, Graves EE, Maxim PG, Loo BW, Bailat C. Design and validation of a dosimetric comparison scheme tailored for ultra-high dose-rate electron beams to support multicenter FLASH preclinical studies. Radiother Oncol 2022; 175:203-209. [PMID: 36030934 DOI: 10.1016/j.radonc.2022.08.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 08/18/2022] [Accepted: 08/19/2022] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND PURPOSE We describe a multicenter cross validation of ultra-high dose rate (UHDR) (>= 40 Gy/s) irradiation in order to bring a dosimetric consensus in absorbed dose to water. UHDR refers to dose rates over 100-1000 times those of conventional clinical beams. UHDR irradiations have been a topic of intense investigation as they have been reported to induce the FLASH effect in which normal tissues exhibit reduced toxicity relative to conventional dose rates. The need to establish optimal beam parameters capable of achieving the in vivo FLASH effect has become paramount. It is therefore necessary to validate and replicate dosimetry across multiple sites conducting UHDR studies with distinct beam configurations and experimental set-ups. MATERIALS AND METHODS Using a custom cuboid phantom with a cylindrical cavity (5 mm diameter by 10.4 mm length) designed to contain three type of dosimeters (thermoluminescent dosimeters (TLDs), alanine pellets, and Gafchromic films), irradiations were conducted at expected doses of 7.5 to 16 Gy delivered at UHDR or conventional dose rates using various electron beams at the Radiation Oncology Departments of the CHUV in Lausanne, Switzerland and Stanford University, CA. RESULTS Data obtained between replicate experiments for all dosimeters were in excellent agreement (±3%). In general, films and TLDs were in closer agreement with each other, while alanine provided the closest match between the expected and measured dose, with certain caveats related to absolute reference dose. CONCLUSION In conclusion, successful cross-validation of different electron beams operating under different energies and configurations lays the foundation for establishing dosimetric consensus for UHDR irradiation studies, and, if widely implemented, decrease uncertainty between different sites investigating the mechanistic basis of the FLASH effect.
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Affiliation(s)
- Patrik Gonçalves Jorge
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Stavros Melemenidis
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Veljko Grilj
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Thierry Buchillier
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Rakesh Manjappa
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Vignesh Viswanathan
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Maude Gondré
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Marie-Catherine Vozenin
- CHUV - Radiation-oncology Laboratory, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Jean-François Germond
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - François Bochud
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Raphaël Moeckli
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Charles Limoli
- Department of Radiation Oncology, University of California, Irvine, CA 92697, USA
| | - Lawrie Skinner
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Hyunsoo Joshua No
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yufan Fred Wu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Murat Surucu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Amy S Yu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Brianna Lau
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jinghui Wang
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Emil Schüler
- Department of Radiation Physics, MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Karl Bush
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Edward E Graves
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Peter G Maxim
- Department of Radiation Oncology, University of California, Irvine, CA 92697, USA
| | - Billy W Loo
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
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22
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Böhlen TT, Germond JF, Bourhis J, Vozenin MC, Ozsahin EM, Bochud F, Bailat C, Moeckli R. Normal tissue sparing by FLASH as a function of single fraction dose: A quantitative analysis. Int J Radiat Oncol Biol Phys 2022; 114:1032-1044. [PMID: 35810988 DOI: 10.1016/j.ijrobp.2022.05.038] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 04/26/2022] [Accepted: 05/24/2022] [Indexed: 11/28/2022]
Abstract
PURPOSE The FLASH effect designates normal tissue sparing by ultra-high dose rate (UHDR) compared to conventional dose rate (CONV) irradiation without compromising tumor control. Understanding the magnitude of this effect and its dependency on dose are essential requirements for an optimized clinical translation of FLASH radiation therapy. In this context, we evaluated available experimental data on the magnitudes of normal tissue sparing provided by the FLASH effect as a function of dose, and followed a phenomenological data-driven approach for its parameterization. METHODS We gathered available in vivo data of the normal tissue sparing of CONV compared to UHDR single fraction doses and converted it to a common scale using isoeffect dose ratios, hereafter referred to as FLASH modifying factors (FMF). We then evaluated the suitability of a piecewise linear function with two pieces to parametrize FMF × D as a function of dose D. RESULTS We found that the magnitude of FMF generally decreases (i.e., sparing increases) as function of single fraction dose and that individual data series can be described by the piecewise linear function. The sparing magnitude appears organ specific. Pooled skin reaction data followed a consistent trend as a function of dose. Average FMF values and their standard deviations were 0.95±0.11 for all data below 10 Gy, 0.92±0.06 for mouse gut data between 10-25 Gy, and 0.96±0.07 and 0.71±0.06 for mammalian skin reaction data between 10-25 Gy and >25 Gy, respectively. CONCLUSIONS The magnitude of normal tissue sparing by FLASH is increasing with dose and is dependent on the irradiated tissue. A piecewise linear function can parameterize currently available individual data series.
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Affiliation(s)
- Till Tobias Böhlen
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Jean-François Germond
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Jean Bourhis
- Department of Radiation Oncology, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Marie-Catherine Vozenin
- Department of Radiation Oncology, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Esat Mahmut Ozsahin
- Department of Radiation Oncology, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - François Bochud
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Raphaël Moeckli
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland..
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Cavallone M, Jorge PG, Moeckli R, Bailat C, Flacco A, Prezado Y, Delorme R. Determination of the ion collection efficiency of the Razor Nano Chamber for ultra-high dose-rate electron beams. Med Phys 2022; 49:4731-4742. [PMID: 35441716 PMCID: PMC9539950 DOI: 10.1002/mp.15675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 04/07/2022] [Accepted: 04/12/2022] [Indexed: 11/10/2022] Open
Abstract
Background Ultra‐high dose‐rate (UHDR) irradiations (>40 Gy/s) have recently garnered interest in radiotherapy (RT) as they can trigger the so‐called “FLASH” effect, namely a higher tolerance of normal tissues in comparison with conventional dose rates when a sufficiently high dose is delivered to the tissue. To transfer this to clinical RT treatments, adapted methods and practical tools for online dosimetry need to be developed. Ionization chambers remain the gold standards in RT but the charge recombination effects may be very significant at such high dose rates, limiting the use of some of these dosimeters. The reduction of the sensitive volume size can be an interesting characteristic to reduce such effects. Purpose In that context, we have investigated the charge collection behavior of the recent IBA Razor™ Nano Chamber (RNC) in UHDR pulses to evaluate its potential interest for FLASH RT. Methods In order to quantify the RNC ion collection efficiency (ICE), simultaneous dose measurements were performed under UHDR electron beams with dose‐rate‐independent Gafchromic™ EBT3 films that were used as the dose reference. A dose‐per‐pulse range from 0.01 to 30 Gy was investigated, varying the source‐to‐surface distance, the pulse duration (1 and 3 μs investigated) and the LINAC gun grid tension as irradiation parameters. In addition, the RNC measurements were corrected from the inherent beam shot‐to‐shot variations using an independent current transformer. An empirical logistic model was used to fit the RNC collection efficiency measurements and the results were compared with the Advanced Markus plane parallel ion chamber. Results The RNC ICE was found to decrease as the dose‐per‐pulse increases, starting from doses above 0.2 Gy/pulse and down to 40% of efficiency at 30 Gy/pulse. The RNC resulted in a higher ICE for a given dose‐per‐pulse in comparison with the Markus chamber, with a measured efficiency found higher than 85 and 55% for 1 and 10 Gy/pulse, respectively, whereas the Markus ICE was of 60 and 25% for the same doses. However, the RNC shows a higher sensitivity to the pulse duration than the Advanced Markus chamber, with a lower efficiency found at 1 μs than at 3 μs, suggesting that this chamber could be more sensitive to the dose rate within the pulse. Conclusions The results confirmed that the small sensitive volume of the RNC ensures higher ICE compared with larger chambers. The RNC was thus found to be a promising online dosimetry tool for FLASH RT and we proposed an ion recombination model to correct its response up to extreme dose‐per‐pulses of 30 Gy.
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Affiliation(s)
- Marco Cavallone
- Institut Curie, PSL Research University, Radiation Oncology Department, Proton Therapy Centre, Centre Universitaire, Orsay, 91898, France.,Laboratoire d'Optique Appliquée, ENSTA Paris, École Polytechnique, CNRS-UMR7639, Institut Polytechnique de Paris, Palaiseau Cedex, 91762, France
| | | | - Raphaël Moeckli
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland
| | - Alessandro Flacco
- Laboratoire d'Optique Appliquée, ENSTA Paris, École Polytechnique, CNRS-UMR7639, Institut Polytechnique de Paris, Palaiseau Cedex, 91762, France
| | - Yolanda Prezado
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, Orsay, 91400, France.,Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, Orsay, 91400, France
| | - Rachel Delorme
- University of Grenoble Alpes, CNRS, Grenoble INP, LPSC-IN2P3, Grenoble, 38000, France.,Imagerie et Modélisation en Neurobiologie et Cancérologie (IMNC), CNRS Univ Paris-Sud, Université Paris-Saclay, Orsay, F-91400, France
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24
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Romano F, Bailat C, Jorge PG, Lerch MLF, Darafsheh A. Ultra‐high dose rate dosimetry: challenges and opportunities for FLASH radiation therapy. Med Phys 2022; 49:4912-4932. [PMID: 35404484 PMCID: PMC9544810 DOI: 10.1002/mp.15649] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 02/03/2022] [Accepted: 02/20/2022] [Indexed: 11/11/2022] Open
Affiliation(s)
- Francesco Romano
- Istituto Nazionale di Fisica Nucleare Sezione di Catania Catania Italy
| | - Claude Bailat
- Institute of Radiation Physics Lausanne University Hospital Lausanne University Switzerland
| | - Patrik Gonçalves Jorge
- Institute of Radiation Physics Lausanne University Hospital Lausanne University Switzerland
- Department of Radiation Oncology Lausanne University Hospital Lausanne Switzerland
- Radio‐Oncology Laboratory DO/CHUV Lausanne University Hospital Lausanne Switzerland
| | | | - Arash Darafsheh
- Department of Radiation Oncology Washington University School of Medicine St. Louis MO 63110 USA
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25
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Juget F, Talip Z, Nedjadi Y, Durán MT, Grundler PV, Zeevaart JR, van der Meulen NP, Bailat C. Precise activity measurements of medical radionuclides using an ionization chamber: a case study with Terbium-161. EJNMMI Phys 2022; 9:19. [PMID: 35286498 PMCID: PMC8921384 DOI: 10.1186/s40658-022-00448-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 03/02/2022] [Indexed: 11/10/2022] Open
Abstract
Background 161Tb draws an increasing interest in nuclear medicine for therapeutic applications. More than 99% of the emitted gamma and X-rays of 161Tb have an energy below 100 keV. Consequently, precise activity measurement of 161Tb becomes inaccurate with radionuclide dose calibrators when using inappropriate containers or calibration factors to account for the attenuation of this low energy radiation. To evaluate the ionization chamber response, the sample activity must be well known. This can be performed using standards traceable to the Système International de Référence, which is briefly described as well as the method to standardize the radionuclides. Methods In this study, the response of an ionization chamber using different container types and volumes was assessed using 161Tb. The containers were filled with a standardized activity solution of 161Tb and measured with a dedicated ionization chamber, providing an accurate response. The results were compared with standardized solutions of high-energy gamma-emitting radionuclides such as 137Cs, 60Co, 133Ba and 57Co. Results For the glass vial type with an irregular glass thickness, the 161Tb measurements gave a deviation of 4.5% between two vials of the same type. The other glass vial types have a much more regular thickness and no discrepancy was observed in the response of the ionization chamber for these type of vials. Measurements with a plastic Eppendorf tube showed stable response, with greater sensitivity than the glass vials. Conclusion Ionization chamber measurements for low-energy gamma emitters (< 100 keV), show deviation depending on the container type used. Therefore, a careful selection of the container type must be done for activity assessment of 161Tb using radionuclide dose calibrators. In conclusion, it was highlighted that appropriate calibration factors must be used for each container geometry when measuring 161Tb and, more generally, for low-energy gamma emitters.
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Affiliation(s)
| | - Zeynep Talip
- Center for Radiopharmaceutical Sciences, ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland
| | | | | | - Pascal V Grundler
- Center for Radiopharmaceutical Sciences, ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland
| | - Jan Rijn Zeevaart
- Radiochemistry, South African Nuclear Energy Corporation (Necsa), Brits, South Africa
| | - Nicholas P van der Meulen
- Center for Radiopharmaceutical Sciences, ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland.,Laboratory of Radiochemistry, Paul Scherrer Institute, Villigen-PSI, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne, Switzerland
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26
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Gonçalves Jorge P, Grilj V, Bourhis J, Vozenin M, Germond J, Bochud F, Bailat C, Moeckli R. Technical note: Validation of an ultrahigh dose rate pulsed electron beam monitoring system using a current transformer for FLASH preclinical studies. Med Phys 2022; 49:1831-1838. [PMID: 35066878 PMCID: PMC9303205 DOI: 10.1002/mp.15474] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 12/20/2021] [Accepted: 01/07/2021] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The Oriatron eRT6 is a linear accelerator (linac) used in FLASH preclinical studies able to reach dose rates ranging from conventional (CONV) up to ultrahigh (UHDR). This work describes the implementation of commercially available beam current transformers (BCTs) as online monitoring tools compatible with CONV and UHDR irradiations for preclinical FLASH studies. METHODS Two BCTs were used to measure the output of the Oriatron eRT6 linac. First, the correspondence between the set nominal beam parameters and those measured by the BCTs was checked. Then, we established the relationship between the total exit charge (measured by BCTs) and the absorbed dose to water. The influence of the pulse width (PW) and the pulse repetition frequency (PRF) at UHDR was characterized, as well as the short- and long-term stabilities of the relationship between the exit charge and the dose at CONV and UHDR. RESULTS The BCTs were able to determine consistently the number of pulses, PW, and PRF. For fixed PW and pulse height, the exit charge measured from BCTs was correlated with the dose, and linear relationships were found with uncertainties of 0.5 % and 3 % in CONV and UHDR mode, respectively. Short- and long-term stabilities of the dose-to-charge ratio were below 1.6 %. CONCLUSIONS We implemented commercially available BCTs and demonstrated their ability to act as online beam monitoring systems to support FLASH preclinical studies with CONV and UHDR irradiations. The implemented BCTs support dosimetric measurements, highlight variations among multiple measurements in a row, enable monitoring of the physics parameters used for irradiation, and are an important step for the safety of the clinical translation of FLASH radiation therapy.
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Affiliation(s)
- Patrik Gonçalves Jorge
- Institute of Radiation PhysicsLausanne University Hospital and University of LausanneLausanneSwitzerland
| | - Veljko Grilj
- Institute of Radiation PhysicsLausanne University Hospital and University of LausanneLausanneSwitzerland
| | - Jean Bourhis
- Radiation‐Oncology DepartmentLausanne University Hospital and University of LausanneLausanneSwitzerland
| | - Marie‐Catherine Vozenin
- Radiation‐Oncology LaboratoryLausanne University Hospital and University of LausanneLausanneSwitzerland
| | - Jean‐François Germond
- Institute of Radiation PhysicsLausanne University Hospital and University of LausanneLausanneSwitzerland
| | - François Bochud
- Institute of Radiation PhysicsLausanne University Hospital and University of LausanneLausanneSwitzerland
| | - Claude Bailat
- Institute of Radiation PhysicsLausanne University Hospital and University of LausanneLausanneSwitzerland
| | - Raphaël Moeckli
- Institute of Radiation PhysicsLausanne University Hospital and University of LausanneLausanneSwitzerland
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Chappuis F, Tran HN, Incerti S, Kacem H, Grilj V, Froidevaux P, Goncalves PJ, Bochud F, Bailat C, Vozenin MC, Desorgher L. FLASH Mechanisms Track (Oral Presentations) MODELLING OF WATER RADIOLYSIS FOR ULTRA-HIGH DOSE RATE (FLASH) ELECTRON BEAMS IN GEANT4-DNA. Phys Med 2022. [DOI: 10.1016/s1120-1797(22)01520-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Böhlen T, Germond JF, Traneus E, Desorgher L, Vozenin MC, Bourhis J, Bailat C, Bochud F, Moeckli R. FLASH Modalities Track (Oral Presentations) CAN UHDR VHEE DEVICES WITH ONLY A FEW FIXED BEAMS PROVIDE COMPETITIVE TREATMENT PLANS COMPARED TO VMAT? Phys Med 2022. [DOI: 10.1016/s1120-1797(22)01514-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Bailat C, Goncalves PJ, Grilj V, Buchillier T, Gondré M, Germond JF, Bochud F, Bourhis J, Vozenin MC, Loo B, Melemenidis S, Moeckli R. DOSIMETRIC COMPARISON SCHEME FACILITATING MULTI-CENTER FLASH-RT PRE-CLINICAL STUDIES. Phys Med 2022. [DOI: 10.1016/s1120-1797(22)01611-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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30
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Desorgher L, Mosimann N, Althaus R, Wirz C, Bailat C, Medici S, Bochud F. Monte Carlo simulations of the whole-body counter at Spiez Laboratory Switzerland: Impact of phantom size and biokinetic model. RADIAT MEAS 2022. [DOI: 10.1016/j.radmeas.2022.106720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Leavitt R, Grilj V, Kacem H, Almeida A, Petit B, Ollivier J, Montay-Gruel P, Goncalves PJ, Bailat C, Vozenin MC. FLASH Mechanisms Track (Oral Presentations) NOT JUST HEALTHY TISSUE SPARING: HYPOXIA DOES NOT IMPACT FLASH-RT ANTI-TUMOR EFFICACY. Phys Med 2022. [DOI: 10.1016/s1120-1797(22)01535-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Gaide O, Herrera F, Sozzi WJ, Gonçalves Jorge P, Kinj R, Bailat C, Duclos F, Bochud F, Germond JF, Gondré M, Boelhen T, Schiappacasse L, Ozsahin M, Moeckli R, Bourhis J. Comparison of ultra-high versus conventional dose rate radiotherapy in a patient with cutaneous lymphoma. Radiother Oncol 2022; 174:87-91. [PMID: 34998899 DOI: 10.1016/j.radonc.2021.12.045] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 12/12/2021] [Accepted: 12/29/2021] [Indexed: 10/19/2022]
Abstract
A patient with a cutaneous lymphoma was treated on the same day for 2 distinct tumors using a 15 Gy single electron dose given in a dose rate of 0.08 Gy/second versus 166 Gy/second. Comparing the two treatments, there was no difference for acute reactions, late effects at 2 years and tumor control.
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Affiliation(s)
- Olivier Gaide
- Department of Dermatology, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Fernanda Herrera
- Radiation Oncology Laboratory, Department of Radiation Oncology. Lausanne University Hospital and University of Lausanne, Switzerland; Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Wendy Jeanneret Sozzi
- Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Patrik Gonçalves Jorge
- Radiation Oncology Laboratory, Department of Radiation Oncology. Lausanne University Hospital and University of Lausanne, Switzerland; Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Rémy Kinj
- Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Fréderic Duclos
- Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Switzerland
| | - François Bochud
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Jean-François Germond
- Radiation Oncology Laboratory, Department of Radiation Oncology. Lausanne University Hospital and University of Lausanne, Switzerland; Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Maud Gondré
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Till Boelhen
- Radiation Oncology Laboratory, Department of Radiation Oncology. Lausanne University Hospital and University of Lausanne, Switzerland; Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Luis Schiappacasse
- Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Mahmut Ozsahin
- Radiation Oncology Laboratory, Department of Radiation Oncology. Lausanne University Hospital and University of Lausanne, Switzerland
| | - Raphaël Moeckli
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Jean Bourhis
- Radiation Oncology Laboratory, Department of Radiation Oncology. Lausanne University Hospital and University of Lausanne, Switzerland; Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Switzerland.
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Oesterle R, Gonçalves Jorge P, Grilj V, Bourhis J, Vozenin M, Germond J, Bochud F, Bailat C, Moeckli R. Implementation and validation of a beam-current transformer on a medical pulsed electron beam LINAC for FLASH-RT beam monitoring. J Appl Clin Med Phys 2021; 22:165-171. [PMID: 34609051 PMCID: PMC8598141 DOI: 10.1002/acm2.13433] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 08/28/2021] [Accepted: 09/13/2021] [Indexed: 12/18/2022] Open
Abstract
PURPOSE To implement and validate a beam current transformer as a passive monitoring device on a pulsed electron beam medical linear accelerator (LINAC) for ultra-high dose rate (UHDR) irradiations in the operational range of at least 3 Gy to improve dosimetric procedures currently in use for FLASH radiotherapy (FLASH-RT) studies. METHODS Two beam current transformers (BCTs) were placed at the exit of a medical LINAC capable of UHDR irradiations. The BCTs were validated as monitoring devices by verifying beam parameters consistency between nominal values and measured values, determining the relationship between the charge measured and the absorbed dose, and checking the short- and long-term stability of the charge-absorbed dose ratio. RESULTS The beam parameters measured by the BCTs coincide with the nominal values. The charge-dose relationship was found to be linear and independent of pulse width and frequency. Short- and long-term stabilities were measured to be within acceptable limits. CONCLUSIONS The BCTs were implemented and validated on a pulsed electron beam medical LINAC, thus improving current dosimetric procedures and allowing for a more complete analysis of beam characteristics. BCTs were shown to be a valid method for beam monitoring for UHDR (and therefore FLASH) experiments.
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Affiliation(s)
- Roxane Oesterle
- Institute of Radiation PhysicsLausanne University Hospital and Lausanne UniversityLausanneSwitzerland
| | - Patrik Gonçalves Jorge
- Institute of Radiation PhysicsLausanne University Hospital and Lausanne UniversityLausanneSwitzerland
| | - Veljko Grilj
- Institute of Radiation PhysicsLausanne University Hospital and Lausanne UniversityLausanneSwitzerland
| | - Jean Bourhis
- Radiation Oncology DepartmentLausanne University Hospital and Lausanne UniversityLausanneSwitzerland
| | - Marie‐Catherine Vozenin
- Radiation Oncology DepartmentLausanne University Hospital and Lausanne UniversityLausanneSwitzerland
| | - Jean‐François Germond
- Institute of Radiation PhysicsLausanne University Hospital and Lausanne UniversityLausanneSwitzerland
| | - François Bochud
- Institute of Radiation PhysicsLausanne University Hospital and Lausanne UniversityLausanneSwitzerland
| | - Claude Bailat
- Institute of Radiation PhysicsLausanne University Hospital and Lausanne UniversityLausanneSwitzerland
| | - Raphaël Moeckli
- Institute of Radiation PhysicsLausanne University Hospital and Lausanne UniversityLausanneSwitzerland
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Böhlen TT, Germond JF, Bourhis J, Vozenin MC, Bailat C, Bochud F, Moeckli R. Technical Note: Break-even dose level for hypofractionated treatment schedules. Med Phys 2021; 48:7534-7540. [PMID: 34609744 PMCID: PMC9298418 DOI: 10.1002/mp.15267] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 09/03/2021] [Accepted: 09/24/2021] [Indexed: 01/10/2023] Open
Abstract
PURPOSE To derive the isodose line R relative to the prescription dose below which irradiated normal tissue (NT) regions benefit from a hypofractionated schedule with an isoeffective dose to the tumor. To apply the formalism to clinical case examples. METHODS From the standard biologically effective dose (BED) equation based on the linear-quadratic (LQ) model, the BED of an NT that receives a relative proportion r of the prescribed dose per fraction for a given α/β-ratio of the tumor, (α/β)T , and NT, (α/β)NT , is derived for different treatment schedules while keeping the BED to the tumor constant. Based on this, the "break-even" isodose line R is then derived. The BED of NT regions that receive doses below R decreases for more hypofractionated treatment schedules, and hence a lower risk for NT injury is predicted in these regions. To assess the impact of a linear behavior of BED for high doses per fraction (>6 Gy), we evaluated BED also using the LQ-linear (LQ-L) model. RESULTS The formalism provides the equations to derive the BED of an NT as function of dose per fraction for an isoeffective dose to the tumor and the corresponding break-even isodose line R. For generic α/β-ratios of (α/β)T = 10 Gy and (α/β)NT = 3 Gy and homogeneous dose in the target, R is 30%. R is doubling for stereotactic treatments for which tumor control correlates with the maximum dose of 100% instead of the encompassing isodose line of 50%. When using the LQ-L model, the notion of a break-even dose level R remains valid up to about 20 Gy per fraction for generic α/β-ratios and D T = 2 ( α / β ) . CONCLUSIONS The formalism may be used to estimate below which relative isodose line R there will be a differential sparing of NT when increasing hypofractionation. More generally, it allows to assess changes of the therapeutic index for sets of isoeffective treatment schedules at different relative dose levels compared to a reference schedule in a compact manner.
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Affiliation(s)
- Till Tobias Böhlen
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Jean-François Germond
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Jean Bourhis
- Radiation-Oncology Department, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Marie-Catherine Vozenin
- Radiation-Oncology Department, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - François Bochud
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Raphaël Moeckli
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
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Durán MT, Juget F, Nedjadi Y, Bochud F, Talip Z, van der Meulen NP, Köster U, Duchemin C, Stora T, Bailat C. Ytterbium-175 half-life determination. Appl Radiat Isot 2021; 176:109893. [PMID: 34425350 DOI: 10.1016/j.apradiso.2021.109893] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 08/08/2021] [Indexed: 10/20/2022]
Abstract
175Yb is a radionuclide that can be generated by neutron capture on 174Yb and whose decay properties make it useful for developing therapeutic radiopharmaceuticals. As it happens with many of the emerging radionuclides for medical uses in recent years, its nuclear data were determined decades ago and are not thoroughly documented nor accurate enough for metrological purposes. The last documented reference for the 175Yb half-life value is 4.185(1) days and dates back to 1989, so a redetermination of the value was considered appropriate before standardization at the Institute of Radiation Physics (IRA, Lausanne, Switzerland) primary measurements laboratory. Three independent measurement methods were used to this purpose: reference ionization chamber (CIR, chambre d'ionization de référence), CeBr3 γ-ray detector with digital electronics and a second CeBr3 detector with analog electronics and single-channel analyzer (SCA) counting. The value obtained for the 175Yb half-life is 4.1615(30) days which shows a 0.56% relative deviation to the last nuclear reference value (ENSDF 2004) and is supported with a detailed calculation of the associated uncertainty.
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Affiliation(s)
| | | | | | | | - Zeynep Talip
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland
| | - Nicholas P van der Meulen
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland; Laboratory of Radiochemistry, Paul Scherrer Institute (PSI), Villigen-PSI, Switzerland
| | - Ulli Köster
- Institut Laue-Langevin (ILL), Grenoble, France
| | - Charlotte Duchemin
- European Organization for Nuclear Research (CERN), Geneva, Switzerland; KU Leuven, Instituut voor Kern-en stralingsfysica (IKS), B-3001 Leuven, Belgium
| | - Thierry Stora
- European Organization for Nuclear Research (CERN), Geneva, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne, Switzerland
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Cherbuin N, Ollivier J, Jorge P, Grilj V, Chappuis F, Desorgher L, Bailat C, Bochud F, Jorge Pires J, Vozenin M. PO-1930 Plasmid DNA damages after FLASH vs conventional dose rate irradiations in various oxygen conditions. Radiother Oncol 2021. [DOI: 10.1016/s0167-8140(21)08381-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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37
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Juget F, Talip Z, Buchillier T, Durán MT, Nedjadi Y, Desorgher L, Bochud F, Grundler P, van der Meulen NP, Bailat C. Determination of the gamma and X-ray emission intensities of terbium-161. Appl Radiat Isot 2021; 174:109770. [PMID: 34051529 DOI: 10.1016/j.apradiso.2021.109770] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 04/12/2021] [Accepted: 05/05/2021] [Indexed: 11/26/2022]
Abstract
In this study, the gamma and X-ray emission intensities of 161Tb were determined using a high-purity germanium spectrometer. The samples used were previously standardised by coincidence counting and Triple to Double Coincidence Ratio (TDCR) methods. A total of 28 gamma-rays and 4 X-rays were measured and compared with previous measurements performed more than 30 years ago. Most of the lines are in agreement, while large discrepancies are observed for 5 lines. The uncertainties have been dramatically decreased with respect to previous measurements giving a better knowledge of the 161 Tb day.
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Affiliation(s)
| | - Zeynep Talip
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland
| | | | | | | | | | | | - Pascal Grundler
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland
| | - Nicholas P van der Meulen
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland; Laboratory of Radiochemistry, Paul Scherrer Institute, Villigen-PSI, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne, Switzerland
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Nedjadi Y, Desorgher L, Juget F, Buchillier T, Bochud F, Bailat C. Activity standardisation of 223Ra. Appl Radiat Isot 2021; 174:109788. [PMID: 34051527 DOI: 10.1016/j.apradiso.2021.109788] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 05/17/2021] [Accepted: 05/18/2021] [Indexed: 09/30/2022]
Abstract
We report here on the primary activity standardisation of a223Ra dichloride solution in equilibrium with its decay daughters. Both the triple-to-double-coincidence-ratio (TDCR) method with an in-house TDCR detector and the CIEMAT-NIST efficiency tracing (CNET) technique with a commercial counter were used. The liquid scintillation efficiencies for both methods are about 6 while the activities they predict with about 0.4% relative standard uncertainty agree within 0.15%. For backup, the solution was also standardised with 4πγ NaI(Tl) integral counting with a well-type NaI(Tl) detector, and efficiencies computed by Monte Carlo simulations using the GEANT code. This simple technique, unused previously for this nuclide, yielded an activity concentration compatible with, but 1% lower than, the one determined by liquid scintillation counting.
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Böhlen TT, Germond JF, Traneus E, Bourhis J, Vozenin MC, Bailat C, Bochud F, Moeckli R. Characteristics of very high-energy electron beams for the irradiation of deep-seated targets. Med Phys 2021; 48:3958-3967. [PMID: 33884618 DOI: 10.1002/mp.14891] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 03/07/2021] [Accepted: 04/06/2021] [Indexed: 01/05/2023] Open
Abstract
PURPOSE Driven by advances in accelerator technology and the potential of exploiting the FLASH effect for the treatment of deep-seated targets (>5 cm), there is an active interest in the construction of devices to deliver very high-energy electron (VHEE) beams for radiation therapy. The application of novel VHEE devices, however, requires an assessment of the tradeoffs between the different beam parameter choices including beam energies, beam divergences, and maximal field sizes. This study systematically examines the dosimetric beam properties of VHEE beams, determining their clinical usefulness while marking their limits of applications for different beam configurations. METHODS We performed Monte Carlo simulations of the dose distributions of electron beams for different energies (25-250 MeV), source-to-surface distances (SSD) (50 cm, 100 cm, parallel), and field sizes (2 cm2 × 2 cm2 to 15 cm2 × 15 cm2 ) in water using a research version of the RayStation treatment planning system (RaySearch Labs 9A IONPG). The beam was simulated using a monoenergetic point source and perfect collimation. Central axis percentage depth dose (PDD) and transverse dose profiles at multiple depths were evaluated and compared to those of MV photon beams. Profile characteristics including therapeutic range (TR) at 90%, proximal fall-off (PFO) at 90%, lateral penumbra (LP) at 90%-10%, and field width (FW) at 90% were obtained. RESULTS Very high-energy electrons beams with SSD 100 cm and parallel beams (infinite SSD) exhibit a linear to near-linear increase of TR as a function of energy in the simulated energy range and reach values well beyond the typical depths of lesions encountered in clinics (<20 cm). Their TR show a marked field size dependence only for field sizes <10 cm2 × 10 cm2 . For VHEE beams with SSD 50 cm, TR are largely reduced (4-8 cm). For beam energies >150 MeV with large SSD (>100 cm), for many configurations, there is no substantial difference in PDD when adding an opposed beam. This may potentially reduce the number of VHEE beams needed for treatment by a factor of two compared to a treatment using lower energies and lower SSD. In order to cover deep-seated targets homogeneously, VHEE devices with a parallel beam must provide a maximum field size up to several centimeters larger than the tumor size. For the investigated diverging beams, there is not such a significant field width reduction with depth for larger fields as it is compensated by divergence. Penumbrae of VHEE beams are smaller than those of clinical MV photon beams for lower depths (<5 cm) but increase quickly for larger depths. There is only a relatively small dependence of penumbra on the SSD of the beam. CONCLUSIONS The findings presented in this study assess the performance of VHEE beams and offer a first estimate of treatment indications and tradeoffs for a given design of a VHEE device. SSD >100 cm results in clinically more favorable PDD. Beam energies of 100 MeV and above are needed to cover common tumors (5-15 cm in-depth) conformally. Higher energies provide an additional benefit specifically for small and deep-seated lesions due to their reduced lateral penumbrae.
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Affiliation(s)
- Till Tobias Böhlen
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland
| | | | | | - Jean Bourhis
- Radiation-oncology department, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Marie-Catherine Vozenin
- Radiation-oncology department, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland
| | - François Bochud
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland
| | - Raphaël Moeckli
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland
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Moeckli R, Gonçalves Jorge P, Grilj V, Oesterle R, Cherbuin N, Bourhis J, Vozenin MC, Germond JF, Bochud F, Bailat C. Commissioning of an ultra-high dose rate pulsed electron beam medical LINAC for FLASH RT preclinical animal experiments and future clinical human protocols. Med Phys 2021; 48:3134-3142. [PMID: 33866565 DOI: 10.1002/mp.14885] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/11/2020] [Accepted: 03/31/2021] [Indexed: 11/05/2022] Open
Abstract
PURPOSE To present the acceptance and the commissioning, to define the reference dose, and to prepare the reference data for a quality assessment (QA) program of an ultra-high dose rate (UHDR) electron device in order to validate it for preclinical animal FLASH radiotherapy (FLASH RT) experiments and for FLASH RT clinical human protocols. METHODS The Mobetron® device was evaluated with electron beams of 9 MeV in conventional (CONV) mode and of 6 and 9 MeV in UHDR mode (nominal energy). The acceptance was performed according to the acceptance protocol of the company. The commissioning consisted of determining the short- and long-term stability of the device, the measurement of percent depth dose curves (PDDs) and profiles at two different positions (with two different dose per pulse regimen) and for different collimator sizes, and the evaluation of the variability of these parameters when changing the pulse width and pulse repetition frequency. Measurements were performed using a redundant and validated dosimetric strategy with alanine and radiochromic films, as well as Advanced Markus ionization chamber for some measurements. RESULTS The acceptance tests were all within the tolerances of the company's acceptance protocol. The linearity with pulse width was within 1.5% in all cases. The pulse repetition frequency did not affect the delivered dose more than 2% in all cases but 90 Hz, for which the larger difference was 3.8%. The reference dosimetry showed a good agreement within the alanine and films with variations of 2.2% or less. The short-term (resp. long-term) stability was less than 1.0% (resp. 1.8%) and was the same in both CONV and UHDR modes. PDDs, profiles, and reference dosimetry were measured at two positions, providing data for two specific dose rates (about 9 Gy/pulse and 3 Gy/pulse). Maximal beam size was 4 and 6 cm at 90% isodose in the two positions tested. There was no difference between CONV and UHDR mode in the beam characteristics tested. CONCLUSIONS The device is commissioned for FLASH RT preclinical biological experiments as well as FLASH RT clinical human protocols.
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Affiliation(s)
- Raphaël Moeckli
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Rue du Grand-Pré 1, Lausanne, CH-1007, Switzerland
| | - Patrik Gonçalves Jorge
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Rue du Grand-Pré 1, Lausanne, CH-1007, Switzerland
| | - Veljko Grilj
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Rue du Grand-Pré 1, Lausanne, CH-1007, Switzerland
| | - Roxane Oesterle
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Rue du Grand-Pré 1, Lausanne, CH-1007, Switzerland
| | - Nicolas Cherbuin
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Rue du Grand-Pré 1, Lausanne, CH-1007, Switzerland
| | - Jean Bourhis
- Radio-Oncology Department, Lausanne University Hospital and Lausanne University, Rue du Bugnon 46, Lausanne, CH-1011, Switzerland
| | - Marie-Catherine Vozenin
- Radio-Oncology Department, Lausanne University Hospital and Lausanne University, Rue du Bugnon 46, Lausanne, CH-1011, Switzerland
| | - Jean-François Germond
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Rue du Grand-Pré 1, Lausanne, CH-1007, Switzerland
| | - François Bochud
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Rue du Grand-Pré 1, Lausanne, CH-1007, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Rue du Grand-Pré 1, Lausanne, CH-1007, Switzerland
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Talip Z, Borgna F, Müller C, Ulrich J, Duchemin C, Ramos JP, Stora T, Köster U, Nedjadi Y, Gadelshin V, Fedosseev VN, Juget F, Bailat C, Fankhauser A, Wilkins SG, Lambert L, Marsh B, Fedorov D, Chevallay E, Fernier P, Schibli R, van der Meulen NP. Production of Mass-Separated Erbium-169 Towards the First Preclinical in vitro Investigations. Front Med (Lausanne) 2021; 8:643175. [PMID: 33968955 PMCID: PMC8100037 DOI: 10.3389/fmed.2021.643175] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 03/22/2021] [Indexed: 01/08/2023] Open
Abstract
The β--particle-emitting erbium-169 is a potential radionuclide toward therapy of metastasized cancer diseases. It can be produced in nuclear research reactors, irradiating isotopically-enriched 168Er2O3. This path, however, is not suitable for receptor-targeted radionuclide therapy, where high specific molar activities are required. In this study, an electromagnetic isotope separation technique was applied after neutron irradiation to boost the specific activity by separating 169Er from 168Er targets. The separation efficiency increased up to 0.5% using resonant laser ionization. A subsequent chemical purification process was developed as well as activity standardization of the radionuclidically pure 169Er. The quality of the 169Er product permitted radiolabeling and pre-clinical studies. A preliminary in vitro experiment was accomplished, using a 169Er-PSMA-617, to show the potential of 169Er to reduce tumor cell viability.
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Affiliation(s)
- Zeynep Talip
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen, Switzerland
| | - Francesca Borgna
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen, Switzerland
| | - Cristina Müller
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen, Switzerland
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Jiri Ulrich
- Laboratory of Radiochemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Charlotte Duchemin
- European Organization for Nuclear Research (CERN), Geneva, Switzerland
- Institute for Nuclear and Radiation Physics, Catholic University of Leuven, Leuven, Belgium
| | - Joao P. Ramos
- European Organization for Nuclear Research (CERN), Geneva, Switzerland
- Institute for Nuclear and Radiation Physics, Catholic University of Leuven, Leuven, Belgium
| | - Thierry Stora
- European Organization for Nuclear Research (CERN), Geneva, Switzerland
| | | | - Youcef Nedjadi
- Institute of Radiation Physics, University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Vadim Gadelshin
- European Organization for Nuclear Research (CERN), Geneva, Switzerland
- Institute of Physics, Johannes Gutenberg University, Mainz, Germany
- Institute of Physics and Technology, Ural Federal University, Yekaterinburg, Russia
| | | | - Frederic Juget
- Institute of Radiation Physics, University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Adelheid Fankhauser
- Analytic Radioactive Materials, Paul Scherrer Institute, Villigen, Switzerland
| | - Shane G. Wilkins
- European Organization for Nuclear Research (CERN), Geneva, Switzerland
| | - Laura Lambert
- European Organization for Nuclear Research (CERN), Geneva, Switzerland
| | - Bruce Marsh
- European Organization for Nuclear Research (CERN), Geneva, Switzerland
| | - Dmitry Fedorov
- Petersburg Nuclear Physics Institute, National Research Center Kurchatov Institute, Gatchina, Russia
| | - Eric Chevallay
- European Organization for Nuclear Research (CERN), Geneva, Switzerland
| | - Pascal Fernier
- European Organization for Nuclear Research (CERN), Geneva, Switzerland
| | - Roger Schibli
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen, Switzerland
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Nicholas P. van der Meulen
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen, Switzerland
- Laboratory of Radiochemistry, Paul Scherrer Institute, Villigen, Switzerland
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Allen BD, Acharya MM, Montay-Gruel P, Jorge PG, Bailat C, Petit B, Vozenin MC, Limoli C. Maintenance of Tight Junction Integrity in the Absence of Vascular Dilation in the Brain of Mice Exposed to Ultra-High-Dose-Rate FLASH Irradiation. Radiat Res 2021; 194:625-635. [PMID: 33348373 DOI: 10.1667/rade-20-00060.1] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 07/01/2020] [Indexed: 01/12/2023]
Abstract
Persistent vasculature abnormalities contribute to an altered CNS microenvironment that further compromises the integrity of the blood-brain barrier and exposes the brain to a host of neurotoxic conditions. Standard radiation therapy at conventional (CONV) dose rate elicits short-term damage to the blood-brain barrier by disrupting supportive cells, vasculature volume and tight junction proteins. While current clinical applications of cranial radiotherapy use dose fractionation to reduce normal tissue damage, these treatments still cause significant complications. While dose escalation enhances treatment of radiation-resistant tumors, methods to subvert normal tissue damage are clearly needed. In this regard, we have recently developed a new modality of irradiation based on the use of ultra-high-dose-rate FLASH that does not induce the classical pathogenic patterns caused by CONV irradiation. In previous work, we optimized the physical parameters required to minimize normal brain toxicity (i.e., FLASH, instantaneous intra-pulse dose rate, 6.9 · 106 Gy/s, at a mean dose rate of 2,500 Gy/s), which we then used in the current study to determine the effect of FLASH on the integrity of the vasculature and the blood-brain barrier. Both early (24 h, one week) and late (one month) timepoints postirradiation were investigated using C57Bl/6J female mice exposed to whole-brain irradiation delivered in single doses of 25 Gy and 10 Gy, respectively, using CONV (0.09 Gy/s) or FLASH (>106 Gy/s). While the majority of changes found one day postirradiation were minimal, FLASH was found to reduce levels of apoptosis in the neurogenic regions of the brain at this time. At one week and one month postirradiation, CONV was found to induce vascular dilation, a well described sign of vascular alteration, while FLASH minimized these effects. These results were positively correlated with and temporally coincident to changes in the immunostaining of the vasodilator eNOS colocalized to the vasculature, suggestive of possible dysregulation in blood flow at these latter times. Overall expression of the tight junction proteins, occludin and claudin-5, which was significantly reduced after CONV irradiation, remained unchanged in the FLASH-irradiated brains at one and four weeks postirradiation. Our data further confirm that, compared to isodoses of CONV irradiation known to elicit detrimental effects, FLASH does not damage the normal vasculature. These data now provide the first evidence that FLASH preserves microvasculature integrity in the brain, which may prove beneficial to cognition while allowing for better tumor control in the clinic.
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Affiliation(s)
- Barrett D Allen
- Department of Radiation Oncology, University of California, Irvine, Irvine, California 92697-2695
| | - Munjal M Acharya
- Department of Radiation Oncology, University of California, Irvine, Irvine, California 92697-2695
| | - Pierre Montay-Gruel
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Patrik Goncalves Jorge
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.,Institute of Radiation Physics/CHUV, Lausanne University Hospital, Lausanne, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics/CHUV, Lausanne University Hospital, Lausanne, Switzerland
| | - Benoît Petit
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Marie-Catherine Vozenin
- Laboratory of Radiation Oncology, Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Charles Limoli
- Department of Radiation Oncology, University of California, Irvine, Irvine, California 92697-2695
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Montay-Gruel P, Markarian M, Allen BD, Baddour JD, Giedzinski E, Jorge PG, Petit B, Bailat C, Vozenin MC, Limoli C, Acharya MM. Ultra-High-Dose-Rate FLASH Irradiation Limits Reactive Gliosis in the Brain. Radiat Res 2021; 194:636-645. [PMID: 32853387 DOI: 10.1667/rade-20-00067.1] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 06/18/2020] [Indexed: 12/20/2022]
Abstract
Encephalic radiation therapy delivered at a conventional dose rate (CONV, 0.1-2.0 Gy/min) elicits a variety of temporally distinct damage signatures that invariably involve persistent indications of neuroinflammation. Past work has shown an involvement of both the innate and adaptive immune systems in modulating the central nervous system (CNS) radiation injury response, where elevations in astrogliosis, microgliosis and cytokine signaling define a complex pattern of normal tissue toxicities that never completely resolve. These side effects constitute a major limitation in the management of CNS malignancies in both adult and pediatric patients. The advent of a novel ultra-high dose-rate irradiation modality termed FLASH radiotherapy (FLASH-RT, instantaneous dose rates ≥106 Gy/s; 10 Gy delivered in 1-10 pulses of 1.8 µs) has been reported to minimize a range of normal tissue toxicities typically concurrent with CONV exposures, an effect that has been coined the "FLASH effect." Since the FLASH effect has now been found to significantly limit persistent inflammatory signatures in the brain, we sought to further elucidate whether changes in astrogliosis might account for the differential dose-rate response of the irradiated brain. Here we report that markers selected for activated astrogliosis and immune signaling in the brain (glial fibrillary acidic protein, GFAP; toll-like receptor 4, TLR4) are expressed at reduced levels after FLASH irradiation compared to CONV-irradiated animals. Interestingly, while FLASH-RT did not induce astrogliosis and TLR4, the expression level of complement C1q and C3 were found to be elevated in both FLASH and CONV irradiation modalities compared to the control. Although functional outcomes in the CNS remain to be cross-validated in response to the specific changes in protein expression reported, the data provide compelling evidence that distinguishes the dose-rate response of normal tissue injury in the irradiated brain.
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Affiliation(s)
- Pierre Montay-Gruel
- Department of Radiation Oncology, University of California, Irvine, Irvine, California 92697-2695
| | - Mineh Markarian
- Department of Radiation Oncology, University of California, Irvine, Irvine, California 92697-2695
| | - Barrett D Allen
- Department of Radiation Oncology, University of California, Irvine, Irvine, California 92697-2695
| | - Jabra D Baddour
- Department of Radiation Oncology, University of California, Irvine, Irvine, California 92697-2695
| | - Erich Giedzinski
- Department of Radiation Oncology, University of California, Irvine, Irvine, California 92697-2695
| | - Patrik Goncalves Jorge
- Laboratory of Radiation Oncology, Department of Radiation Oncology. Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Benoît Petit
- Laboratory of Radiation Oncology, Department of Radiation Oncology. Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Claude Bailat
- Laboratory of Radiation Oncology, Department of Radiation Oncology. Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Marie-Catherine Vozenin
- Laboratory of Radiation Oncology, Department of Radiation Oncology. Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Charles Limoli
- Department of Radiation Oncology, University of California, Irvine, Irvine, California 92697-2695
| | - Munjal M Acharya
- Department of Radiation Oncology, University of California, Irvine, Irvine, California 92697-2695
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Montay-Gruel P, Acharya MM, Gonçalves Jorge P, Petit B, Petridis IG, Fuchs P, Leavitt R, Petersson K, Gondré M, Ollivier J, Moeckli R, Bochud F, Bailat C, Bourhis J, Germond JF, Limoli CL, Vozenin MC. Hypofractionated FLASH-RT as an Effective Treatment against Glioblastoma that Reduces Neurocognitive Side Effects in Mice. Clin Cancer Res 2021; 27:775-784. [PMID: 33060122 PMCID: PMC7854480 DOI: 10.1158/1078-0432.ccr-20-0894] [Citation(s) in RCA: 125] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 09/03/2020] [Accepted: 10/12/2020] [Indexed: 11/16/2022]
Abstract
PURPOSE Recent data have shown that single-fraction irradiation delivered to the whole brain in less than tenths of a second using FLASH radiotherapy (FLASH-RT), does not elicit neurocognitive deficits in mice. This observation has important clinical implications for the management of invasive and treatment-resistant brain tumors that involves relatively large irradiation volumes with high cytotoxic doses. EXPERIMENTAL DESIGN Therefore, we aimed at simultaneously investigating the antitumor efficacy and neuroprotective benefits of FLASH-RT 1-month after exposure, using a well-characterized murine orthotopic glioblastoma model. As fractionated regimens of radiotherapy are the standard of care for glioblastoma treatment, we incorporated dose fractionation to simultaneously validate the neuroprotective effects and optimized tumor treatments with FLASH-RT. RESULTS The capability of FLASH-RT to minimize the induction of radiation-induced brain toxicities has been attributed to the reduction of reactive oxygen species, casting some concern that this might translate to a possible loss of antitumor efficacy. Our study shows that FLASH and CONV-RT are isoefficient in delaying glioblastoma growth for all tested regimens. Furthermore, only FLASH-RT was found to significantly spare radiation-induced cognitive deficits in learning and memory in tumor-bearing animals after the delivery of large neurotoxic single dose or hypofractionated regimens. CONCLUSIONS The present results show that FLASH-RT delivered with hypofractionated regimens is able to spare the normal brain from radiation-induced toxicities without compromising tumor cure. This exciting capability provides an initial framework for future clinical applications of FLASH-RT.See related commentary by Huang and Mendonca, p. 662.
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Affiliation(s)
- Pierre Montay-Gruel
- Laboratory of Radiation Oncology/DO/Radio-Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Munjal M Acharya
- Department of Radiation Oncology, University of California, Irvine, California
| | - Patrik Gonçalves Jorge
- Laboratory of Radiation Oncology/DO/Radio-Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Switzerland
- Institute of Radiation Physics/CHUV, Lausanne University Hospital, Switzerland
| | - Benoît Petit
- Laboratory of Radiation Oncology/DO/Radio-Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Ioannis G Petridis
- Laboratory of Radiation Oncology/DO/Radio-Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Philippe Fuchs
- Laboratory of Radiation Oncology/DO/Radio-Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Ron Leavitt
- Laboratory of Radiation Oncology/DO/Radio-Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Kristoffer Petersson
- Laboratory of Radiation Oncology/DO/Radio-Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Switzerland
- Institute of Radiation Physics/CHUV, Lausanne University Hospital, Switzerland
| | - Maude Gondré
- Laboratory of Radiation Oncology/DO/Radio-Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Switzerland
- Institute of Radiation Physics/CHUV, Lausanne University Hospital, Switzerland
| | - Jonathan Ollivier
- Laboratory of Radiation Oncology/DO/Radio-Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Raphael Moeckli
- Institute of Radiation Physics/CHUV, Lausanne University Hospital, Switzerland
| | - François Bochud
- Institute of Radiation Physics/CHUV, Lausanne University Hospital, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics/CHUV, Lausanne University Hospital, Switzerland
| | - Jean Bourhis
- Laboratory of Radiation Oncology/DO/Radio-Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Switzerland
| | | | - Charles L Limoli
- Department of Radiation Oncology, University of California, Irvine, California
| | - Marie-Catherine Vozenin
- Laboratory of Radiation Oncology/DO/Radio-Oncology/CHUV, Lausanne University Hospital and University of Lausanne, Switzerland.
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Schüller A, Heinrich S, Fouillade C, Subiel A, De Marzi L, Romano F, Peier P, Trachsel M, Fleta C, Kranzer R, Caresana M, Salvador S, Busold S, Schönfeld A, McEwen M, Gomez F, Solc J, Bailat C, Linhart V, Jakubek J, Pawelke J, Borghesi M, Kapsch RP, Knyziak A, Boso A, Olsovcova V, Kottler C, Poppinga D, Ambrozova I, Schmitzer CS, Rossomme S, Vozenin MC. The European Joint Research Project UHDpulse – Metrology for advanced radiotherapy using particle beams with ultra-high pulse dose rates. Phys Med 2020; 80:134-150. [DOI: 10.1016/j.ejmp.2020.09.020] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 08/17/2020] [Accepted: 09/23/2020] [Indexed: 02/08/2023] Open
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Nedjadi Y, Juget F, Desorgher L, Durán MT, Bochud F, Müller C, Talip Z, van der Meulen NP, Bailat C. Activity standardisation of 161Tb. Appl Radiat Isot 2020; 166:109411. [PMID: 32961523 DOI: 10.1016/j.apradiso.2020.109411] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/18/2020] [Accepted: 09/04/2020] [Indexed: 01/16/2023]
Abstract
161Tb, which emits low-energy β-- and γ-particles in addition to conversion and Auger electrons, has aroused increased interest for medical imaging and therapy. To support the use of this radionuclide, a161Tb solution was standardised using the β-γ coincidence technique, as well as the TDCR method. The solution had 4.5·10-3% of 160Tb impurities. Primary coincidence measurements, with plastic or liquid scintillators for beta detection, were carried out using both analogue and digital electronics. TDCR measurements using defocusing, grey filtering and quenching for varying the efficiency were also made. Monte Carlo calculations were used to compute the detection efficiency. The coincidence measurements with analogue electronics and the TDCR show a good consistency, and are compatible with the digital coincidence results within uncertainties. An ampoule of this solution was submitted to the BIPM as a contribution to the international reference system.
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Affiliation(s)
| | | | | | | | | | - Cristina Müller
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland
| | - Zeynep Talip
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland
| | - Nicholas P van der Meulen
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland; Laboratory of Radiochemistry, Paul Scherrer Institute, Villigen-PSI, Switzerland
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47
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Moeckli R, Germond JF, Bailat C, Bochud F, Vozenin MC, Bourhis J. In Regard to van Marlen et al. Int J Radiat Oncol Biol Phys 2020; 107:1012-1013. [DOI: 10.1016/j.ijrobp.2020.04.038] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 04/22/2020] [Indexed: 11/16/2022]
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48
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Gondré M, Jorge PG, Vozenin MC, Bourhis J, Bochud F, Bailat C, Moeckli R. Optimization of Alanine Measurements for Fast and Accurate Dosimetry in FLASH Radiation Therapy. Radiat Res 2020; 194:573-579. [DOI: 10.1667/rr15568.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 02/17/2020] [Indexed: 11/03/2022]
Affiliation(s)
| | | | - Marie-Catherine Vozenin
- Radio-Oncology Department, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Jean Bourhis
- Radio-Oncology Department, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
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Durán MT, Nedjadi Y, Juget F, Bochud F, Bailat C. Evaluation of digital pulse processing techniques for a β-γ coincidence counting system. Appl Radiat Isot 2020; 159:109100. [PMID: 32250773 DOI: 10.1016/j.apradiso.2020.109100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 02/17/2020] [Accepted: 02/24/2020] [Indexed: 11/17/2022]
Abstract
Signal processing is a core part of any electronic chain for radioactivity measurement systems and can influence measurement results drastically. A thorough study of the different alternatives for this treatment is especially worthwhile when developing a new digital system. This article describes an evaluation performed to optimize the digital pulse processing stage of the β-γ coincidence counting system at the Institute of Radiation Physics (IRA) designated laboratory for the activity unit. This study is a part of IRA's digitalization project to modernize the aging analog electronic hardware of its primary measurement systems. The β-γ coincidence counting system consists of a plastic scintillation detector in the beta channel and a well-type NaI detector in the gamma channel. Six pulse shaping digital filters along with amplitude calculation algorithms were implemented to obtain beta and gamma pulse amplitude values. In addition, four timing digital filters and time pick-off methods were set up to calculate arrival times (timestamps) for the pulses generated by both detectors. Filter parameters and algorithm settings were adjusted to obtain the best performance. Combination of filters into traditional two channel (fast for timing and slow for shaping) or one channel configuration using dCFD (digital constant fraction discrimination) and LE (leading edge) time pick-off methods were also tested and compared to study the whole digital pulse processing system, using both real measurement signals (241Am, 137Cs, 60Co and 166mHo) and simulated reference pulses. The results of these tests were quantified by evaluating the following metrics: processing speed, signal-to-noise ratio (SNR) at different energies, gamma energy resolution, time measurement accuracy, time resolution and detection efficiency. The results of this evaluation provide a rational ground to assess the system and help decide which digital pulse processing (DPP) method should be the most appropriate.
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Affiliation(s)
- M Teresa Durán
- Institute of Radiation Physics (IRA), Lausanne, Switzerland.
| | - Youcef Nedjadi
- Institute of Radiation Physics (IRA), Lausanne, Switzerland
| | - Frédéric Juget
- Institute of Radiation Physics (IRA), Lausanne, Switzerland
| | | | - Claude Bailat
- Institute of Radiation Physics (IRA), Lausanne, Switzerland
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50
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Durán MT, Juget F, Nedjadi Y, Bochud F, Grundler PV, Gracheva N, Müller C, Talip Z, van der Meulen NP, Bailat C. Determination of 161Tb half-life by three measurement methods. Appl Radiat Isot 2020; 159:109085. [PMID: 32250758 DOI: 10.1016/j.apradiso.2020.109085] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 12/30/2019] [Accepted: 02/14/2020] [Indexed: 11/16/2022]
Abstract
The radiolanthanide 161Tb is being studied as an alternative to 177Lu for targeted radionuclide tumor therapy. Both β--particle emitters show similar chemical behavior and decay characteristics, but 161Tb delivers additional conversion and Auger electron emissions that may enhance the therapeutic efficacy. In this study, the half-life of 161Tb was determined by a combination of three independent measurement systems: reference ionization chamber (CIR, chambre d'ionization de référence), portable ionization chamber (TCIR) and a CeBr3 γ-emission detector with digital electronics. The half-life determined for 161Tb is 6.953(2) days, showing a significant improvement in the uncertainty, which is one order of magnitude lower, with a deviation of 0.91% from the last nuclear data reference value. The previous large uncertainty of the half-life had a direct impact on activity measurements. Now it is no more an obstacle to a primary standardization.
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Affiliation(s)
| | | | | | | | - Pascal V Grundler
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland
| | - Nadezda Gracheva
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland
| | - Cristina Müller
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland
| | - Zeynep Talip
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland
| | - Nicholas P van der Meulen
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland; Laboratory of Radiochemistry, Paul Scherrer Institute, Villigen-PSI, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne, Switzerland
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