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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; 120:287-300. [PMID: 38493902 DOI: 10.1016/j.ijrobp.2024.03.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [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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Wahabi JM, Wong JHD, Mahdiraji GA, Ung NM. Feasibility of determining external beam radiotherapy dose using LuSy dosimeter. J Appl Clin Med Phys 2024; 25:e14387. [PMID: 38778567 PMCID: PMC11163501 DOI: 10.1002/acm2.14387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 04/20/2024] [Accepted: 04/26/2024] [Indexed: 05/25/2024] Open
Abstract
INTRODUCTION Radiation dose measurement is an essential part of radiotherapy to verify the correct delivery of doses to patients and ensure patient safety. Recent advancements in radiotherapy technology have highlighted the need for fast and precise dosimeters. Technologies like FLASH radiotherapy and magnetic-resonance linear accelerators (MR-LINAC) demand dosimeters that can meet their unique requirements. One promising solution is the plastic scintillator-based dosimeter with high spatial resolution and real-time dose output. This study explores the feasibility of using the LuSy dosimeter, an in-house developed plastic scintillator dosimeter for dose verification across various radiotherapy techniques, including conformal radiotherapy (CRT), intensity-modulated radiation therapy (IMRT), volumetric-modulated arc therapy (VMAT), and stereotactic radiosurgery (SRS). MATERIALS AND METHODS A new dosimetry system, comprising a new plastic scintillator as the sensing material, was developed and characterized for radiotherapy beams. Treatment plans were created for conformal radiotherapy, IMRT, VMAT, and SRS and delivered to a phantom. LuSy dosimeter was used to measure the delivered dose for each plan on the surface of the phantom and inside the target volumes. Then, LuSy measurements were compared against an ionization chamber, MOSFET dosimeter, radiochromic films, and dose calculated using the treatment planning system (TPS). RESULTS For CRT, surface dose measurement by LuSy dosimeter showed a deviation of -5.5% and -5.4% for breast and abdomen treatment from the TPS, respectively. When measuring inside the target volume for IMRT, VMAT, and SRS, the LuSy dosimeter produced a mean deviation of -3.0% from the TPS. Surface dose measurement resulted in higher TPS discrepancies where the deviations for IMRT, VMAT, and SRS were -2.0%, -19.5%, and 16.1%, respectively. CONCLUSION The LuSy dosimeter was feasible for measuring radiotherapy doses for various treatment techniques. Treatment delivery verification enables early error detection, allowing for safe treatment delivery for radiotherapy patients.
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Affiliation(s)
- Janatul Madinah Wahabi
- Department of Biomedical ImagingFaculty of MedicineUniversiti MalayaKuala LumpurMalaysia
- Radiotherapy and Oncology DepartmentNational Cancer InstitutePutrajayaMalaysia
| | - Jeannie Hsiu Ding Wong
- Department of Biomedical ImagingFaculty of MedicineUniversiti MalayaKuala LumpurMalaysia
- Universiti Malaya Research Imaging Centre (UMRIC), Faculty of MedicineUniversiti MalayaKuala LumpurMalaysia
| | | | - Ngie Min Ung
- Clinical Oncology UnitFaculty of MedicineUniversiti MalayaKuala LumpurMalaysia
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Bertinetti A, Garcia T, Palmer B, Rodrigues M, Bradshaw T, Vija AH, Culberson W. Active and passive dosimetry for beta-emitting radiopharmaceutical therapy agents in a custom SPECT/CT compatible phantom. Phys Med Biol 2024; 69:115031. [PMID: 38684165 DOI: 10.1088/1361-6560/ad450c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Accepted: 04/29/2024] [Indexed: 05/02/2024]
Abstract
Objective. This work introduces a novel approach to performing active and passive dosimetry for beta-emitting radionuclides in solution using common dosimeters. The measurements are compared to absorbed dose to water (Dw) estimates from Monte Carlo (MC) simulations. We present a method for obtaining absorbed dose to water, measured with dosimeters, from beta-emitting radiopharmaceutical agents using a custom SPECT/CT compatible phantom for validation of Monte Carlo based absorbed dose to water estimates.Approach. A cylindrical, acrylic SPECT/CT compatible phantom capable of housing an IBA EFD diode, Exradin A20-375 parallel plate ion chamber, unlaminated EBT3 film, and thin TLD100 microcubes was constructed for the purpose of measuring absorbed dose to water from solutions of common beta-emitting radiopharmaceutical therapy agents. The phantom is equipped with removable detector inserts that allow for multiple configurations and is designed to be used for validation of image-based absorbed dose estimates with detector measurements. Two experiments with131I and one experiment with177Lu were conducted over extended measurement intervals with starting activities of approximately 150-350 MBq. Measurement data was compared to Monte Carlo simulations using the egs_chamber user code in EGSnrc 2019.Main results. Agreement withink= 1 uncertainty between measured and MC predictedDwwas observed for all dosimeters, except the A20-375 ion chamber during the second131I experiment. Despite the agreement, the measured values were generally lower than predicted values by 5%-15%. The uncertainties atk = 1 remain large (5%-30% depending on the dosimeter) relative to other forms of radiation therapy.Significance. Despite high uncertainties, the overall agreement between measured and simulated absorbed doses is promising for the use of dosimeter-based RPT measurements in the validation of MC predictedDw.
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Affiliation(s)
| | | | - Benjamin Palmer
- University of Wisconsin-Madison, WI, United States of America
| | | | - Tyler Bradshaw
- University of Wisconsin-Madison, WI, United States of America
| | - A Hans Vija
- Siemens Healthineers, United States of America
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Esplen N, Egoriti L, Planche T, Rädel S, Koay HW, Humphries B, Ren X, Ford N, Hoehr C, Gottberg A, Bazalova-Carter M. Dosimetric characterization of a novel UHDR megavoltage X-ray source for FLASH radiobiological experiments. Sci Rep 2024; 14:822. [PMID: 38191885 PMCID: PMC10774358 DOI: 10.1038/s41598-023-50412-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Accepted: 12/19/2023] [Indexed: 01/10/2024] Open
Abstract
A first irradiation platform capable of delivering 10 MV X-ray beams at ultra-high dose rates (UHDR) has been developed and characterized for FLASH radiobiological research at TRIUMF. Delivery of both UHDR (FLASH mode) and low dose-rate conventional (CONV mode) irradiations was demonstrated using a common source and experimental setup. Dose rates were calculated using film dosimetry and a non-intercepting beam monitoring device; mean values for a 100 μA pulse (peak) current were nominally 82.6 and 4.40 × 10-2 Gy/s for UHDR and CONV modes, respectively. The field size for which > 40 Gy/s could be achieved exceeded 1 cm down to a depth of 4.1 cm, suitable for total lung irradiations in mouse models. The calculated delivery metrics were used to inform subsequent pre-clinical treatments. Four groups of 6 healthy male C57Bl/6J mice were treated using thoracic irradiations to target doses of either 15 or 30 Gy using both FLASH and CONV modes. Administration of UHDR X-ray irradiation to healthy mouse models was demonstrated for the first time at the clinically-relevant beam energy of 10 MV.
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Affiliation(s)
- Nolan Esplen
- Physics and Astronomy, University of Victoria, Victoria, V8P 5C2, Canada
| | - Luca Egoriti
- TRIUMF, Vancouver, V6T 2A3, Canada
- Chemistry, University of British Columbia, Vancouver, V6T 1Z1, Canada
| | | | | | | | | | - Xi Ren
- Physics and Astronomy, University of British Columbia, Vancouver, V6T 1Z1, Canada
| | - Nancy Ford
- Physics and Astronomy, University of British Columbia, Vancouver, V6T 1Z1, Canada
- Oral Biological and Medical Sciences, University of British Columbia, Vancouver, V6T 1Z1, Canada
| | - Cornelia Hoehr
- Physics and Astronomy, University of Victoria, Victoria, V8P 5C2, Canada
- TRIUMF, Vancouver, V6T 2A3, Canada
| | - Alexander Gottberg
- Physics and Astronomy, University of Victoria, Victoria, V8P 5C2, Canada
- TRIUMF, Vancouver, V6T 2A3, Canada
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Kaiyum R, Schruder CW, Mermut O, Rink A. Investigation of cyanine-based infrared dyes as calibrants in radiochromic films. Med Phys 2023; 50:8034-8043. [PMID: 37633840 DOI: 10.1002/mp.16674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 07/03/2023] [Accepted: 07/29/2023] [Indexed: 08/28/2023] Open
Abstract
BACKGROUND Radiochromic material such as lithium pentacosa-10,12-diynoate (LiPCDA) has been suggested as the radiation-sensitive material for real-time in vivo fiber-optic dosimetry. In this configuration, micron-thick radiochromic coating would measure the absorbed dose, where a major challenge is the uncertainty in the active material thickness, necessitating calibration. A homogeneously incorporated inert infrared (IR) dye, which must also be stable in ambient conditions and against radiolysis, can be added to the radiochromic film to enable optical calibration. PURPOSE This study investigates four commercial cyanine-based dyes (IR-783, IR-806, IR-868, and IR-880) for use as an optical calibrant in fiber-optic radiochromic dosimeters. METHODS All dyes were dissolved in water to confirm solubility. IR-783 and IR-806 were dissolved in 10% w/w gelatin solution and coated onto a polyester substrate, which were then sandwiched between two layers of adhesives forming IR-783 and IR-806 films. A second batch of IR dyes in gelatin incorporated the LiPCDA, and was coated onto substrate and sandwiched between adhesive to form IR dye + LiPCDA films. The absorbance spectra of the films were measured periodically (176 and 102 days for IR-dye films, and IR dye + LiPCDA, respectively). The average percentage absorbance, normalized to day 1, was fit to either a single or a double exponential decay model to calculate the spectral stability lifetime (τ1 , τ2 ). Films were irradiated using a 6 MV LINAC beam with a standard setup of 100 source to axis distance (SAD), 10 cm × 10 cm field size and 1.5 cm depth. The change in absorbance of the IR-dye + LiPCDA films were measured after they were irradiated to 1, 2, 5, 10, and 20 Gy at 3 Gy/min. RESULTS Only IR-783 and IR-806 were sufficiently water soluble. In gelatin matrix, these dyes demonstrated a decrease in absorbance with time for IR-783 and IR-806 dyes, with IR-783 films having an average τ1 = 73 ± 7 days and IR-806 films τ1 = 7 ± 3 days. When combined with LiPCDA, IR-806 degraded, losing its original peak at ∼820 nm. Similarly, IR-783, combined with LiPCDA, showed signs of degradation; however, its original absorbance peak was still observed at ∼800 nm. In the IR-783 + LiPCDA films, the IR-783 dye had a τ = 4 ± 1 days, an order of magnitude faster than the IR-783 with no LiPCDA films. When exposed to x-ray irradiation, the IR-783 dye in the IR-783 + LiPCDA films showed no change in absorbance with increasing absorbed dose. In contrast, the LiPCDA in the films responded as expected, increasing in optical density with increased absorbed dose. CONCLUSIONS IR-783 and IR-806 dyes were observed to degrade over time following exponential decay curves. IR-806 could not be combined with the LiPCDA without degrading. The combination of IR-783 with LiPCDA demonstrated single exponential decay behavior at a comparatively faster rate than films that did not have LiPCDA. IR-783 was insensitive to ionizing radiation and thus may be suitable for thickness correction, but an alternative manufacturing procedure may need to be developed.
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Affiliation(s)
- Rohith Kaiyum
- Department of Physics and Astronomy, York University, Toronto, Canada
- TECHNA Institute, University Health Network, Toronto, Canada
| | - Christopher W Schruder
- Department of Physics and Astronomy, York University, Toronto, Canada
- TECHNA Institute, University Health Network, Toronto, Canada
| | - Ozzy Mermut
- Department of Physics and Astronomy, York University, Toronto, Canada
| | - Alexandra Rink
- Department of Medical Physics, Princess Margaret Cancer Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
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Endarko E, Aisyah S, Hariyanto AP, Haekal M, Kavilani N, Syafi'i A. Dosimetry Evaluation of Treatment Planning Systems in Patient-Specific 3D Printed Anthropomorphic Phantom for Breast Cancer after Mastectomy using a Single-Beam 3D-CRT Technique for Megavoltage Electron Radiation Therapy. J Biomed Phys Eng 2023; 13:217-226. [PMID: 37312896 PMCID: PMC10258204 DOI: 10.31661/jbpe.v0i0.2111-1428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 03/20/2022] [Indexed: 06/15/2023]
Abstract
Background The patient-specific 3D printed anthropomorphic phantom is used for breast cancer after mastectomy developed by the laboratory of medical physics and biophysics, Department of Physics, Institut Teknologi Sepuluh Nopember, Indonesia. This phantom is applied to simulate and measure the radiation interactions occurring in the human body either using the treatment planning system (TPS) or direct measurement with external beam therapy (EBT) 3 film. Objective This study aimed to provide dose measurements in the patient-specific 3D printed anthropomorphic phantom using a TPS and direct measurements using single-beam three-dimensional conformal radiation therapy (3DCRT) technique with electron energy of 6 MeV. Material and Methods In this experimental study, the patient-specific 3D printed anthropomorphic phantom was used for post-mastectomy radiation therapy. TPS on the phantom was conducted using a 3D-CRT technique with RayPlan 9A software. The single-beam radiation was delivered to the phantom with an angle perpendicular to the breast plane at 337.3° at 6 MeV with a total prescribed dose of 5000 cGy/25 fractions with 200 cGy per fraction. Results The doses at planning target volume (PTV) and right lung confirmed a non-significant difference both for TPS and direct measurement with P-values of 0.074 and 0.143, respectively. The dose at the spinal cord showed statistically significant differences with a P-value of 0.002. The result presented a similar skin dose value using either TPS or direct measurement. Conclusion The patient-specific 3D printed anthropomorphic phantom for breast cancer after mastectomy on the right side has good potential as an alternative to the evaluation of dosimetry for radiation therapy.
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Affiliation(s)
- Endarko Endarko
- Department of Physics, Institut Teknologi Sepuluh Nopember, Kampus ITS - Sukolilo Surabaya 60111, East Java, Indonesia
| | - Siti Aisyah
- Medical Physicist of Radiotherapy Installation, Naval Hospital Dr. Ramelan, Surabaya 60244, East Java, Indonesia
| | - Aditya Prayugo Hariyanto
- Department of Physics, Institut Teknologi Sepuluh Nopember, Kampus ITS - Sukolilo Surabaya 60111, East Java, Indonesia
| | - Mohammad Haekal
- Department of Physics, Institut Teknologi Sepuluh Nopember, Kampus ITS - Sukolilo Surabaya 60111, East Java, Indonesia
| | - Nandia Kavilani
- Medical Physicist of Radiotherapy Installation, Naval Hospital Dr. Ramelan, Surabaya 60244, East Java, Indonesia
| | - Ahmad Syafi'i
- Medical Physicist of Radiotherapy Installation, Naval Hospital Dr. Ramelan, Surabaya 60244, East Java, Indonesia
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Piliero MA, Pupillo F, Presilla S. A diffuse reflectance spectrophotometer for radiation dosimetry of EBT3 GAFchromic films. RADIAT MEAS 2022. [DOI: 10.1016/j.radmeas.2022.106777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Dunn L, Godwin G, Hellyer J, Xu X. A method for time‐independent film dosimetry: Can we obtain accurate patient‐specific QA results at any time postirradiation? J Appl Clin Med Phys 2022; 23:e13534. [PMID: 35049118 PMCID: PMC8906213 DOI: 10.1002/acm2.13534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 12/15/2021] [Accepted: 12/30/2021] [Indexed: 11/09/2022] Open
Affiliation(s)
- Leon Dunn
- St Vincent's GenesisCare Centre for radiation oncology St Vincent's Hospital Basement Level Building C, 41 Victoria Parade, Fitzroy VIC 3065 Melbourne Victoria 3065 Australia
| | - Guy Godwin
- Redland Icon Cancer Care Bayside Business Park, 16/24 Weippin St, Cleveland QLD Brisbane Queensland 4163 Australia
| | - James Hellyer
- Macquarie University GenesisCare Centre for radiation oncology Hospital Building Suite 1, Level B2, 3 Technology Pl, Macquarie University NSW Sydney New South Wales 2109 Australia
| | - Xiaolei Xu
- St Vincent's GenesisCare Centre for radiation oncology St Vincent's Hospital Basement Level Building C, 41 Victoria Parade, Fitzroy VIC 3065 Melbourne Victoria 3065 Australia
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Mulet L, Barreto I, Cohen GN, Damato AL, Mauceri T, Pursley J, Deufel CL. Protocol for the measurement of the absorbed dose rate to water for a planar 32P beta emitting brachytherapy source: A multi-institutional validation. Brachytherapy 2022; 21:120-127. [PMID: 34706854 PMCID: PMC8810704 DOI: 10.1016/j.brachy.2021.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 08/04/2021] [Accepted: 08/08/2021] [Indexed: 01/03/2023]
Abstract
PURPOSE This is a multi-institutional report on inter-observer and inter-instrument variation in the calibration of the absorbed dose rate for a planar 32P beta emitting brachytherapy source. Measurement accuracy is essential since the dose profile is steep and the source is used for the treatment of tumors that are located in close proximity to healthy nervous system structures. METHODS AND MATERIALS An RIC-100 32P source was calibrated by three institutions using their own equipment and following their standard procedures. The first institution calibrated the source with an electron diode and EBT3 film. The second institution used an electron diode. The third institution used HD810 film. Additionally, each institution was asked to calibrate the source using an electron diode and procedure that was shared among all institutions and shipped along with the radiation source. The dose rate was reported in units of cGy*min-1 at a water equivalent depth of 1 mm. RESULTS Close agreement was observed in the measurements from different users and equipment. The variation across all diode detectors and institutions had a standard deviation of 1.8% and maximum difference of 4.6%. The observed variation among two different diode systems used within the same institution had a mean difference of 1.6% and a maximum variation of 1.8%. The variations among film and diode systems used within the same institution had a mean difference of 2.9% and a maximum variation of 4.3% CONCLUSIONS: The absorbed dose rate measurement protocol of the planar beta-emitting 32P source permits consistent dosimetry across three institutions and five different electron diode and radiochromic film systems. The methodologies presented herein should enable measurement consistency among other clinical users, which will help ensure high quality patient treatments and outcomes analysis.
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Affiliation(s)
- Liana Mulet
- Department of Radiology, University of Florida, Gainesville, FL 32608
| | - Izabella Barreto
- Department of Radiology, University of Florida, Gainesville, FL 32608
| | - Gil’ad N. Cohen
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Antonio L. Damato
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Thomas Mauceri
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA
| | - Jennifer Pursley
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA
| | - Christopher L. Deufel
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN 55905,Corresponding author: , Tel: 1-507-293-4019 Fax: 1-507-284-0079
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Heng VJ, Serban M, Seuntjens J, Renaud MA. Ion chamber and film-based quality assurance of mixed electron-photon radiation therapy. Med Phys 2021; 48:5382-5395. [PMID: 34224144 DOI: 10.1002/mp.15081] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/27/2021] [Accepted: 06/06/2021] [Indexed: 11/09/2022] Open
Abstract
PURPOSE In previous work, we demonstrated that mixed electron-photon radiation therapy (MBRT) produces treatment plans with improved normal tissue sparing and similar target coverage, when compared to photon-only plans. The purpose of this work was to validate the MBRT delivery process on a Varian TrueBeam accelerator and laying the groundwork for a patient-specific quality assurance (QA) protocol based on ion chamber point measurements and 2D film measurements. METHODS MC beam models used to calculate the MBRT dose distributions of each modality (photons/electrons) were validated with a single-angle beam MBRT treatment plan delivered on a slab of Solid Water phantom with a film positioned at a depth of 2 cm. The measured film absorbed dose was compared to the calculated dose. To validate clinical deliveries, a polymethyl methacrylate (PMMA) cylinder was machined and holes were made to fit an ionization chamber. A complex MBRT plan involving a photon arc and three electron delivery angles was created with the aim of reproducing a clinically realistic dose distribution in typical soft tissue sarcoma tumours of the extremities. The treatment plan was delivered on the PMMA cylinder. Point measurements were taken with an Exradin A1SL chamber at two nominal depths: 1.4 cm and 2.1 cm. The plan was also delivered on a second identical phantom with an insert at 2 cm depth, where a film was placed. An existing EGSnrc user-code, SPRRZnrc, was modified to calculate the stopping power ratios between any materials in the same voxelized geometry used for dose calculation purposes. This modified code, called SPRXYZnrc, was used to calculate a correction factor, k MBRT , accounting for the differences in electron fluence spectrum at the measurement point compared to that at reference conditions. The uncertainty associated with neglecting potential ionization chamber fluence perturbation correction factors using this approach was estimated. RESULTS The film measurement from the Solid Water phantom treatment plan was in good agreement with the simulated dose distribution, with a gamma pass rate of 96.1% for a 3%/2 mm criteria. For the PMMA phantom delivery, for the same gamma criteria, the pass rate was 97.3%. The ion chamber measurements of the total delivered dose agreed with the MC-simulated dose within 2.1%. The beam quality correction factors amounted to, at most, a 4% correction on the ion chamber measurement. However, individual contribution of low electron energies proved difficult to precisely measure due to their steep dose gradients, with disagreements of up to 28% ± 15% at 2.1 cm depth (6 MeV). Ion chamber measurement procedure of electron beams was achieved in less than 5 min, and the entire validation process including phantom setup was performed in less than 30 min. CONCLUSION The agreement between measured and simulated MBRT doses indicates that the dose distributions obtained from the MBRT treatment planning algorithm are realistically achievable. The SPRXYZnrc MC code allowed for convenient calculations of k MBRT simultaneously with the dose distributions, laying the groundwork for patient-specific QA protocol practical for clinical use. Further investigation is needed to establish the accuracy of our ionization chamber correction factors k MBRT calculations at low electron energies.
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Affiliation(s)
- Veng Jean Heng
- Department of Physics and Medical Physics Unit, McGill University, Montreal, QC, Canada
| | - Monica Serban
- Department of Medical Physics, McGill University Health Centre, Montreal, QC, Canada
| | - Jan Seuntjens
- Medical Physics Unit, McGill University and Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Marc-André Renaud
- Department of Mathematics and Industrial Engineering, Polytechnique Montréal, Montreal, QC, Canada
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Prikhodko VV, Alexeyev AS, Guskov PA, Novikov SG, Somov AI, Svetukhin VV. Technical Note: ID-card-size dosimeter based on radiochromic films for continuous personnel monitoring. Med Phys 2021; 48:3216-3222. [PMID: 33893658 DOI: 10.1002/mp.14893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 04/06/2021] [Accepted: 04/06/2021] [Indexed: 11/08/2022] Open
Abstract
PURPOSE This paper is aimed at investigating the feasibility of developing a personal dosimeter of cumulative radiation dose which would incorporate the following features: 1) a small size compared to that of a proximity ID card; 2) instant dose readout; 3) no power source; 4) moderate cost. The dosimeter is proposed as a potential replacement for TLD and OSL dosimeters used by nuclear industry workers and some medical staff groups. METHODS An original detector design is developed containing a two-color LED, two photodetectors located in one plane covered with a mirror coating. The power necessary for the operation comes from an RFID reader. A small (5x5 mm) piece of Gafchromic EBT3 photochromic film sensitive to both X-ray and gamma radiation is used as a sensor. Irradiation of samples under X-ray and gamma radiation is carried out in the dose range of 0.1 cGy-1 Gy. The transmittance spectra are measured in the 300 nm-1100 nm spectral range. RESULTS Several prototypes of the dosimeter are presented, the distinctive features of which are the absence of the power source, easy transmitting of the dosimetric data via a RF channel, and a slim form factor. Several sources of dose uncertainties are analyzed and ways to eliminate them are outlined. The average dose confidence interval (α = 0.05) calculated from the response curve is shown to equal 0.02 cGy. This makes it possible to reliably measure doses as low as 0.1 cGy, which corresponds to the minimum value claimed for Gafchromic EBT3. CONCLUSIONS The proposed idea of an ID-card-size dosimeter is feasible and has a number of advantages over TLD and OSL dosimeters, in particular, instant reading of the dose data using RFID/NFC readers, and a possibility of integrating into ERP systems.
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Affiliation(s)
- Victor V Prikhodko
- S.P. Kapitsa Research Institute of Technology of Ulyanovsk State University, Ulyanovsk, Russia
| | - Alexander S Alexeyev
- S.P. Kapitsa Research Institute of Technology of Ulyanovsk State University, Ulyanovsk, Russia
| | - Pavel A Guskov
- S.P. Kapitsa Research Institute of Technology of Ulyanovsk State University, Ulyanovsk, Russia
| | - Sergey G Novikov
- S.P. Kapitsa Research Institute of Technology of Ulyanovsk State University, Ulyanovsk, Russia
| | - Andrey I Somov
- S.P. Kapitsa Research Institute of Technology of Ulyanovsk State University, Ulyanovsk, Russia
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Radiochromic Films for the Two-Dimensional Dose Distribution Assessment. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11052132] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Radiochromic films are mainly used for two-dimensional dose verification in photon, electron, and proton therapy treatments. Moreover, the radiochromic film types available today allow their use in a wide dose range, corresponding to applications from low-medical diagnostics to high-dose beam profile measurements in charged particle medical accelerators. An in-depth knowledge of the characteristics of radiochromic films, of their operating principles, and of the dose reading techniques is of paramount importance to exploit all the features of this interesting and versatile radiation detection system. This short review focuses on these main aspects by considering the most recent works on the subject.
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Calibration of the EBT3 Gafchromic Film Using HNN Deep Learning. BIOMED RESEARCH INTERNATIONAL 2021; 2021:8838401. [PMID: 33628820 PMCID: PMC7892216 DOI: 10.1155/2021/8838401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 10/22/2020] [Accepted: 01/17/2021] [Indexed: 11/19/2022]
Abstract
To achieve a dose distribution conformal to the target volume while sparing normal tissues, intensity modulation with steep dose gradient is used for treatment planning. To successfully deliver such treatment, high spatial and dosimetric accuracy are crucial and need to be verified. With high 2D dosimetry resolution and a self-development property, the Ashland Inc. product EBT3 Gafchromic film is a widely used quality assurance tool designed especially for this. However, the film should be recalibrated each quarter due to the “aging effect,” and calibration uncertainties always exist between individual films even in the same lot. Recently, artificial neural networks (ANN) are applied to many fields. If a physicist can collect the calibration data, it could be accumulated to be a substantial ANN data input used for film calibration. We therefore use the Keras functional Application Program Interface to build a hierarchical neural network (HNN), with the inputs of net optical densities, pixel values, and inverse transmittances to reveal the delivered dose and train the neural network with deep learning. For comparison, the film dose calculated using red-channel net optical density with power function fitting was performed and taken as a conventional method. The results show that the percentage error of the film dose using the HNN method is less than 4% for the aging effect verification test and less than 4.5% for the intralot variation test; in contrast, the conventional method could yield errors higher than 10% and 7%, respectively. This HNN method to calibrate the EBT film could be further improved by adding training data or adjusting the HNN structure. The model could help physicists spend less calibration time and reduce film usage.
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Santos J, Silva S, Sarmento S. Optimized method for in vivo dosimetry with small films in pelvic IOERT for rectal cancer. Phys Med 2020; 81:20-30. [PMID: 33338728 DOI: 10.1016/j.ejmp.2020.11.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 11/09/2020] [Accepted: 11/15/2020] [Indexed: 11/28/2022] Open
Abstract
PURPOSE Intra-Operative Electron Radiation Therapy (IOERT) is used to treat rectal cancer at our institution, and in vivo measurements with Gafchromic EBT3® films were introduced as quality assurance. The purpose of this work was to quantify the uncertainties associated with digitization of very small EBT3 films irradiated simultaneously, in order to optimize in vivo dosimetry for IOERT. METHODS Film samples of different sizes - M1 (5×5cm2), M2 (1.5×1.5 cm2), M3 (1.0×1.5 cm2) and M4 (0.75×1.5 cm2) - were used to quantify typical variations (uncertainties) due to scanner fluctuations, misalignment, film inhomogeneity, long-term effect of film cutting, small rotations, film curling, edge effects and the influence of opaque templates. Fitting functions and temporal validity of sensitometric curves were also assessed. RESULTS Film curling, intra-film variability and scanner fluctuations are important effects that need to be minimized or considered in the uncertainty budget. Small rotations, misalignments and film cutting have little or no influence on the readings. Most fitting functions perform well, but the quantity used for dose quantification determines over- or under-valuation of dose in the long term. Edge effects and the influence of opaque templates need to be well understood, to allow optimization of methodology to the intended purpose. CONCLUSION The proposed method allows practical and simultaneous digitization of up to ten small irradiated film samples, with an experimental uncertainty of 1%.
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Affiliation(s)
- Joana Santos
- Physics and Astronomy Department, Faculty of Sciences, University of Porto, Portugal; Medical Physics, Radiobiology and Radiation Protection Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal
| | - Sofia Silva
- Medical Physics, Radiobiology and Radiation Protection Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal; Medical Physics Service, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal
| | - Sandra Sarmento
- Management, Outcomes Research and Economics in Healthcare Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal; Medical Physics Service, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.
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Esplen N, Mendonca MS, Bazalova-Carter M. Physics and biology of ultrahigh dose-rate (FLASH) radiotherapy: a topical review. Phys Med Biol 2020; 65:23TR03. [PMID: 32721941 DOI: 10.1088/1361-6560/abaa28] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Ultrahigh dose-rate radiotherapy (RT), or 'FLASH' therapy, has gained significant momentum following various in vivo studies published since 2014 which have demonstrated a reduction in normal tissue toxicity and similar tumor control for FLASH-RT when compared with conventional dose-rate RT. Subsequent studies have sought to investigate the potential for FLASH normal tissue protection and the literature has been since been inundated with publications on FLASH therapies. Today, FLASH-RT is considered by some as having the potential to 'revolutionize radiotherapy'. FLASH-RT is considered by some as having the potential to 'revolutionize radiotherapy'. The goal of this review article is to present the current state of this intriguing RT technique and to review existing publications on FLASH-RT in terms of its physical and biological aspects. In the physics section, the current landscape of ultrahigh dose-rate radiation delivery and dosimetry is presented. Specifically, electron, photon and proton radiation sources capable of delivering ultrahigh dose-rates along with their beam delivery parameters are thoroughly discussed. Additionally, the benefits and drawbacks of radiation detectors suitable for dosimetry in FLASH-RT are presented. The biology section comprises a summary of pioneering in vitro ultrahigh dose-rate studies performed in the 1960s and early 1970s and continues with a summary of the recent literature investigating normal and tumor tissue responses in electron, photon and proton beams. The section is concluded with possible mechanistic explanations of the FLASH normal-tissue protection effect (FLASH effect). Finally, challenges associated with clinical translation of FLASH-RT and its future prospects are critically discussed; specifically, proposed treatment machines and publications on treatment planning for FLASH-RT are reviewed.
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Affiliation(s)
- Nolan Esplen
- Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada
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Asfia A, Deepak B, Novak JI, Rolfe B, Kron T. Infill selection for 3D printed radiotherapy immobilisation devices. Biomed Phys Eng Express 2020; 6. [DOI: 10.1088/2057-1976/abb981] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 09/17/2020] [Indexed: 12/19/2022]
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Tiwari A, Sunderland J, Graves SA, Strand S, Flynn R. Absorbed dose distributions from beta-decaying radionuclides: Experimental validation of Monte Carlo tools for radiopharmaceutical dosimetry. Med Phys 2020; 47:5779-5790. [PMID: 32955755 DOI: 10.1002/mp.14463] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 06/22/2020] [Accepted: 08/04/2020] [Indexed: 11/05/2022] Open
Abstract
PURPOSE This study aims to experimentally validate the Monte Carlo generated absorbed doses from the beta particles emitted by 90 Y and 177 Lu using radiochromic EBT3 film-based dosimetry. METHODS Line sources of 90 Y and 177 Lu were inserted longitudinally through blocks of low-density polyethylene and tissue-equivalent slabs of cortical bone and lung equivalent plastics. Radiochromic film (Gafchromic EBT3) was laser cut to accommodate orthogonal line sources of radioactivity, and the film was sandwiched intimately between the rectangular blocks to achieve charged particle equilibrium. Line sources consisted of plastic capillary tube of length (13 ± 0.1) cm, with 0.42-mm inner diameter and a wall thickness of 0.21 mm. 90 Y line sources were prepared from a solution of dissolved 90 Y resin microspheres. 177 Lu line sources were prepared from an aliquot of 177 Lu-DOTATATE. Film exposures were conducted for durations ranging from 10 min to 38 h. Radiochromic film calibration was performed by irradiation with 6-MV-bremsstrahlung x rays from a calibrated linear accelerator, in accordance with literature recommendations. Experimental geometries were precisely simulated within the GATE Monte Carlo toolkit, which has previously been used for the generation of dose point kernels. RESULTS The mean percentage difference between measured and simulated absorbed doses were 5.04% and 7.21% for 90 Y and 177 Lu beta absorbed dose in the range of (0.1-10) Gy. Additionally, 1D gamma analysis using a local 10%/1 mm gamma criterion was performed to compare the absorbed dose distributions. The percentage of measurement points passing the gamma criterion, averaged over all tests, was 93.5%. CONCLUSIONS We report the experimental validation of Monte Carlo derived beta absorbed dose distributions for 90 Y and 177 Lu, solidifying the validity of using Monte Carlo-based methods for estimating absorbed dose from beta emitters. Overall, excellent agreement was observed between the experimental beta absorbed doses in the linear region of the radiochromic film and the GATE Monte Carlo simulations demonstrating that radiochromic film dosimetry has sufficient sensitivity and spatial resolution to be used as a tool for measuring beta decay absorbed dose distributions.
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Affiliation(s)
- Ashok Tiwari
- Department of Radiology, University of Iowa Hospitals and Clinics, 200 Hawkins Dr., Iowa City, IA, 52242-1077, USA.,Department of Physics, University of Iowa, 203 Van Allen Hall, Iowa City, IA, 52242-1479, USA
| | - John Sunderland
- Department of Radiology, University of Iowa Hospitals and Clinics, 200 Hawkins Dr., Iowa City, IA, 52242-1077, USA.,Department of Physics, University of Iowa, 203 Van Allen Hall, Iowa City, IA, 52242-1479, USA
| | - Stephen A Graves
- Department of Radiology, University of Iowa Hospitals and Clinics, 200 Hawkins Dr., Iowa City, IA, 52242-1077, USA.,Department of Radiation Oncology, University of Iowa Hospitals and Clinics, 200 Hawkins Dr., Iowa City, IA, 52242-1089, USA
| | - Sarah Strand
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, 200 Hawkins Dr., Iowa City, IA, 52242-1089, USA
| | - Ryan Flynn
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, 200 Hawkins Dr., Iowa City, IA, 52242-1089, USA
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Apipunyasopon L, Chaloeiparp C, Wiriyatharakij T, Phaisangittisakul N. Characterization of natural rubber as a bolus material for electron beam radiotherapy. Rep Pract Oncol Radiother 2020; 25:725-729. [PMID: 32684861 DOI: 10.1016/j.rpor.2020.06.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 04/21/2020] [Accepted: 06/15/2020] [Indexed: 10/23/2022] Open
Abstract
Background Bolus is an accessory that is directly placed on the surface region to shift the radiation dose up to the skin during high energy photon and electron beam irradiations. The aim of this study was to mold the bolus using natural rubber material and assess both the physical and dosimetric characteristics. Materials and methods A natural rubber with additional plasticizer material was fabricated as a bolus sheet. The physical properties of natural rubber bolus sheets have been investigated using computed tomography (CT) images. Gafchromic EBT3 films were used to acquire the dose at depth of 0, 2, 3, and 3.5 cm for the 9-MeV therapeutic electron beam. A comparison of our natural rubber bolus sheets to the commercial bolus sheets was studied. Results The in-house natural rubber bolus sheets with the thickness of 0.32 and 0.52 cm were successfully made. Relative electron density of the two sheets was consistent with each other. However, similar to the commercial boluses, the natural rubber boluses were not provided with the same CT number over the whole sheet. Different bolus material gave different dose at the surface. Both material and thickness of the bolus showed a stronger impact on the dose beyond the depth of maximum dose. Conclusion Because of the density, simple fabrication, and vast availability, natural rubber material has an effective potential to be used as a bolus sheet in radiotherapy.
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Affiliation(s)
- Lukkana Apipunyasopon
- Department of Radiological Technology and Medical Physics, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok 10330, Thailand
| | - Chalitpon Chaloeiparp
- Division of Radiology, King Chulalongkorn Memorial Hospital, Bangkok 10330, Thailand
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Pushpavanam K, Inamdar S, Dutta S, Bista T, Sokolowski T, Sapareto S, Rege K. Plasmonic gel nanocomposites for detection of high energy electrons. J Mater Chem B 2020; 8:4930-4939. [PMID: 32281998 DOI: 10.1039/d0tb00241k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Radiation therapy is a common treatment modality employed in the treatment of cancer. High energy photons are the primary source of radiation but when administered, they leave an exit dose resulting in radiation damage to the adjacent healthy tissues. To overcome this, high energy electrons are employed in cases of skin cancer to minimize radiation induced toxicity. Despite these advances, measurement of delivered radiation remains a challenge due to limitations with existing dosimeters including labor intensive fabrication, complex read-out techniques and post-irradiation instability. To overcome these limitations, we have developed a novel colorimetric plasmonic gel nanocomposite for the detection of therapeutic levels of radiation delivered in electron beam therapy. The plasmonic nanocomposite consists of an agarose gel matrix encapsulating precursor gold ions, which are reduced to gold nanoparticles as a result of exposure to high energy electrons. The formation of gold nanoparticles renders a change in color to the agarose matrix, resulting in the formation of plasmonic gel nanocomposites. The intensity of the color formed exhibits a linear relation with the delivered electron dose, which can be quantified using absorbance spectroscopy. The plasmonic gel nanocomposites were able to detect doses employed in fractionated electron therapy, including in an anthropomorphic phantom used for planning radiation treatments in the clinic. Furthermore, the use of glutathione as a quenching agent facilitated qualitative and quantitative spatial mapping of the delivered dose. Our results indicate that the ease of fabrication, simplicity of detection and quantification using absorbance spectroscopy, determination of spatial dose profiles, and relatively low cost make the plasmonic gel nanocomposite technology attractive for detecting electron doses in the clinic.
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Affiliation(s)
- Karthik Pushpavanam
- Chemical Engineering, Arizona State University, 501 E. Tyler Mall, ECG 303, Tempe, AZ 85287-6106 85287, USA.
| | - Sahil Inamdar
- Chemical Engineering, Arizona State University, 501 E. Tyler Mall, ECG 303, Tempe, AZ 85287-6106 85287, USA.
| | - Subhadeep Dutta
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Tomasz Bista
- Banner-MD Anderson Cancer Center, Gilbert, AZ 85234, USA
| | | | | | - Kaushal Rege
- Chemical Engineering, Arizona State University, 501 E. Tyler Mall, ECG 303, Tempe, AZ 85287-6106 85287, USA.
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Miloichikova I, Bulavskaya A, Cherepennikov Y, Gavrikov B, Gargioni E, Belousov D, Stuchebrov S. Feasibility of clinical electron beam formation using polymer materials produced by fused deposition modeling. Phys Med 2019; 64:188-194. [PMID: 31515019 DOI: 10.1016/j.ejmp.2019.07.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 07/17/2019] [Accepted: 07/17/2019] [Indexed: 10/26/2022] Open
Abstract
The main challenge in electron external beam radiation therapy with clinical accelerators is the absence of integrated systems to form irregular fields. The current approach to provide conformal irradiation is to use additional metallic shaping blocks, with inefficient and expensive workflows. This work presents a simple method to form therapeutic electron fields using 3D printed samples. These samples are manufactured by fused deposition modeling, which can affect crucial properties, such as material homogeneity, due to the presence of residual air-filled cavities. The applicability of this method was therefore investigated with a set of experiments and Monte Carlo simulations aimed at determining the electron depth dose distribution in polymer materials. The results show that therapeutic electron beams with energies 6-20 MeV can be effectively absorbed using these polymeric samples. The model developed in this study provides a way to assess the dose distribution in such materials and to calculate the appropriate thickness of polymer samples for therapeutic electron beam formation. It is shown that for total absorption of 6 MeV electron beams the material thickness should be at least 4 cm, while this value should be at least 8 cm for 12 MeV and 11 cm for 20 MeV, respectively. The results can be used to further develop 3D printing procedures for medical electron beam profile formation, allowing the creation of a collimator or absorber with patient-specific configuration using rapid prototyping systems, thus contributing to improve the accuracy of dose delivery in electron radiotherapy within a short manufacturing time.
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Affiliation(s)
- Irina Miloichikova
- National Research Tomsk Polytechnic University, Lenina Avenue 30, 634050 Tomsk, Russia; Cancer Research Institute of Tomsk NRMC RAS, Kooperativny Street 5, 634050 Tomsk, Russia.
| | - Angelina Bulavskaya
- National Research Tomsk Polytechnic University, Lenina Avenue 30, 634050 Tomsk, Russia
| | - Yury Cherepennikov
- National Research Tomsk Polytechnic University, Lenina Avenue 30, 634050 Tomsk, Russia
| | - Boris Gavrikov
- Moscow City Oncology Hospital №62, Istra 27, 143423 Moscow, Russia
| | - Elisabetta Gargioni
- University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - Dmitrij Belousov
- Institute of Automation and Electrometry SB RAS, Academician Koptyug Avenue 1, 630090 Novosibirsk, Russia
| | - Sergei Stuchebrov
- National Research Tomsk Polytechnic University, Lenina Avenue 30, 634050 Tomsk, Russia
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Holla R, Khanna D, Pillai BK, Jafar Ali KV, Renil Mon PS, Clinto CO, Ganesh T. An Experimental Slope Method for a More Accurate Measurement of Relative Radiation Doses using Radiographic and Radiochromic Films and Its Application to Megavoltage Small-Field Dosimetry. J Med Phys 2019; 44:145-155. [PMID: 31576063 PMCID: PMC6764177 DOI: 10.4103/jmp.jmp_17_19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
PURPOSE An experimental method using the linear portion of the relative film dose-response curve for radiographic and radiochromic films is presented, which can be used to determine the relative depth doses in a variety of very small, medium, and large radiation fields and relative output factors (ROFs) for small fields. MATERIALS AND METHODS The film slope (FS) method was successfully applied to obtain the percentage depth doses (PDDs) for external beams of photon and electrons from a Synergy linear accelerator (Elekta AB, Stockholm, Sweden) under reference conditions of 10 cm × 10 cm for photon beam and nominal 10 cm × 10 cm size applicator for electron beam. For small-field dosimetry, the FS method was applied to EDR2 films (Carestream Health, Rochester, NY) for 6 MV photon beam from a linac (Elekta AB, Stockholm, Sweden) and small, circular radiosurgery cones (Elekta AB, Stockholm, Sweden) with diameters of 5, 7.5, 10, 12.5, and 15 mm. The ROFs for all these cones and central axis PDDs for 5, 10, and 15 mm diameter cones were determined at source-to-surface distance of 100 cm. The ROFs for small fields of CyberKnife system were determined using this technique with Gafchromic EBT3 film (Ashland, NJ, USA). The PDDs and ROFs were compared with ion chamber (IC) and Monte Carlo (MC) simulated values. RESULTS The maximum percentage deviation of PDDFS with PDDIC for 4, 6, and 15 MV photon beams was within 1.9%, 2.5%, and 1.4%, respectively, up to 20-cm depth. The maximum percentage deviation of PDDFS with PDDIC for electron beams was within 3% for energy range studied of 8-15 MeV. The gamma passing rates of PDDFS with PDDIC were above 96.5% with maximum gamma value of >2, occurring at the zero depths for 4, 6, and 15 MV photons. For electron beams, the gamma passing rates between PDDFS with PDDIC were above 97.7% with a maximum gamma value of 0.9, 1.3, and 0.7 occurring at the zero depth for 8, 12, and 15 MeV. For small field of 5-mm cone, the ROFFS was 0.665 ± 0.021 as compared to 0.674 by MC method. The maximum percentage deviation between PDDFS and PDDMC was 3% for 5 mm and 10 mm and 2% for 15 mm cones with 1D gamma passing rates, respectively, of 95.5%, 96%, and 98%. For CyberKnife system, the ROFFS using EBT3 film and MC published values agrees within 0.2% for for 5 mm cone. CONCLUSIONS The authors have developed a novel and more accurate method for the relative dosimetry of photon and electron beams. This offers a unique method to determine PDD and ROF with a high spatial resolution in fields of steep dose gradient, especially in small fields.
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Affiliation(s)
- Raghavendra Holla
- Department of Physics, Karunya Institute of Technology and Sciences, Coimbatore, Tamil Nadu, India.,Department of Medical Physics, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham, Kochi, Kerala, India
| | - D Khanna
- Department of Physics, Karunya Institute of Technology and Sciences, Coimbatore, Tamil Nadu, India
| | - Bhaskaran K Pillai
- Department of Medical Physics, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham, Kochi, Kerala, India
| | - K V Jafar Ali
- Department of Medical Physics, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham, Kochi, Kerala, India
| | - P S Renil Mon
- Department of Medical Physics, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham, Kochi, Kerala, India
| | - C O Clinto
- Department of Medical Physics, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham, Kochi, Kerala, India
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Soliman K, Adili M, Alrushoud A. Radiation dose verification of an X-ray based blood irradiator using EBT3 radiochromic films calibrated using Gamma Knife machine. Rep Pract Oncol Radiother 2019; 24:369-374. [PMID: 31198412 DOI: 10.1016/j.rpor.2019.05.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 03/06/2019] [Accepted: 05/11/2019] [Indexed: 11/20/2022] Open
Abstract
Aim Blood irradiators (BI) initial acceptance testing and routine annual dosimetry checks require radiation dose measurements in order to comply with regulatory requirements. Background Traditionally thermo-luminescence dosimeters (TLD) have been used to measure the dose. The EBT3 film is reported to be a better dosimeter for low energy X-rays than its predecessors EBT2 and EBT. To the best of our knowledge, the use of EBT3 films to perform dosimetry on X-ray based BI has not been reported yet. Materials and methods We performed routine radiation dosimetry checks using EBT3 films on a new X-ray based BI and compared the results with TLD dosimetry. Calibration films were irradiated with radiation beam from a Co-60 Gamma Knife (GK) radiosurgery machine and, alternatively, using an Ir-192 high dose rate (HDR) brachytherapy device. The films were calibrated to cover a wide dose range from 1 to 40 Gy. Such a wide dose range has not been reported yet in BI film dosimetry. Results We obtained a relative difference of about 6.6% between doses measured using TLD and those measured using EBT3 films. Both irradiation methods using GK or HDR were found to be adequate for the calibration of the EBT3 Gafchromic films. Conclusions We recommend the use of EBT3 films in routine X-ray based BI dosimetry checks. The presented method takes advantage of available radiotherapy equipment that can be efficiently used for EBT3 films calibration. The method is fast, reproducible and saves valuable medical physicist's time.
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Affiliation(s)
- Khaled Soliman
- Medical Physics Department, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Marouf Adili
- Medical Physics Department, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Abdullah Alrushoud
- Medical Physics Department, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
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Simulation and experimental validation of a prototype electron beam linear accelerator for preclinical studies. Phys Med 2019; 60:50-57. [DOI: 10.1016/j.ejmp.2019.03.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 03/12/2019] [Accepted: 03/17/2019] [Indexed: 11/24/2022] Open
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Abstract
The change in optical properties of GafChromic films depends not only on the absorbed dose, but also on the linear energy transfer (LET) of the ionizing radiation. The influence of LET on the film dose-response relationship is especially important when films are applied for dosimetry of energetic charged particles. In the present study, we examined the response of the unlaminated EBT3 and MD-V3 films to proton, deuterium and helium beams with energies in the range of several megaelectronvolts (MeV). Films were exposed to doses up to 200 Gy and a model based on the bimolecular chemical reaction was chosen to fit the measured film signals. The LET in the active layers of the films and the dose correction factors were computed with Monte Carlo software TRIM. Signal quenching, observed for all ion beams in comparison to x-rays, was investigated as a function of the LET in the range of 10-100 keV µm-1. The response of the films got weaker with increasing the LET and showed no dependence on the ion species. The LET effect was quantified by introducing a modified expression for the relative effectiveness (RE) by which a unique RE value is assigned to a single LET. The RE defined in that way decreased from about 90% for LET of 10 keV µm-1 to less than 50% for LET of 100 keV µm-1. Similar behavior was observed for EBT3 and MD-V3 film models.
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Affiliation(s)
- V. Grilj
- Center for Radiological Research, Columbia University Irving Medical Center, New York, NY, USA
| | - D. J. Brenner
- Center for Radiological Research, Columbia University Irving Medical Center, New York, NY, USA
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Experimental validatıon of peripheral dose distribution of electron beams for eclipse electron Monte Carlo algorithm. JOURNAL OF RADIOTHERAPY IN PRACTICE 2018. [DOI: 10.1017/s1460396917000784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractAimThe accuracy of two calculation algorithms of the Varian Eclipse treatment planning system (TPS), the electron Monte Carlo algorithm (eMC) and general Gaussian pencil beam algorithm (GGPB) for calculating peripheral dose distribution of electron beams was investigated.MethodsPeripheral dose measurements were carried out for 6, 9, 12, 15, 18 and 22 MeV electron beams using parallel plate ionisation chamber and EBT3 film in the slab phantom. Measurements were performed for 6×6, 10×10 and 25×25 cm2 cone sizes at dmax of each energy up to 20 cm beyond the field edges. The measured and TPS calculated data were compared.ResultsThe TPS underestimated the out-of-field doses. The difference between measured and calculated doses increase with the cone size. For ionisation chamber measurement, the largest deviation between calculated and measured doses is <4·29% using the eMC, but can increase up to 8·72% of the distribution using GGPB. For film measurement, the minimum gamma analysis passing rates between measured and calculated dose distributions for all field sizes and energies used in this study were 91·2 and 74·7% for eMC and GGPB, respectively.FindingsThe use of GGPB for planning large field treatments with 6 MeV could lead to inaccuracies of clinical significance.
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Jong W, Ung N, Tiong A, Rosenfeld A, Wong J. Characterisation of a MOSFET-based detector for dose measurement under megavoltage electron beam radiotherapy. Radiat Phys Chem Oxf Engl 1993 2018. [DOI: 10.1016/j.radphyschem.2017.11.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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27
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Hermida-López M, Brualla L. Absorbed dose distributions from ophthalmic 106 Ru/ 106 Rh plaques measured in water with radiochromic film. Med Phys 2018; 45:1699-1707. [PMID: 29399810 DOI: 10.1002/mp.12777] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 12/19/2017] [Accepted: 01/06/2018] [Indexed: 11/08/2022] Open
Abstract
PURPOSE Brachytherapy with 106 Ru/106 Rh plaques offers good outcomes for small-to-medium choroidal melanomas and retinoblastomas. The dose measurement of the plaques is challenging, due to the small range of the emitted beta particles and steep dose gradients involved. The scarce publications on film dosimetry of 106 Ru/106 Rh plaques used solid phantoms. This work aims to develop a practical method for measuring the absorbed dose distribution in water produced by 106 Ru/106 Rh plaques using EBT3 radiochromic film. METHODS Experimental setups were developed to determine the dose distribution at a plane perpendicular to the symmetry axis of the plaque and at a plane containing the symmetry axis. One CCA and two CCX plaques were studied. The dose maps were obtained with the FilmQA Pro 2015 software, using the triple-channel dosimetry method. The measured dose distributions were compared to published Monte Carlo simulation and experimental data. RESULTS A good agreement was found between measurements and simulations, improving upon published data. Measured reference dose rates agreed within the experimental uncertainty with data obtained by the manufacturer using a scintillation detector, with typical differences below 5%. The attained experimental uncertainty was 4.1% (k = 1) for the perpendicular setup, and 7.9% (k = 1) for the parallel setup. These values are similar or smaller than those obtained by the manufacturer and other authors, without the need of solid phantoms that are not available to most users. CONCLUSIONS The proposed method may be useful to the users to perform quality assurance preclinical tests of 106 Ru/106 Rh plaques.
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Affiliation(s)
- Marcelino Hermida-López
- NCTeam, Strahlenklinik, Universitätsklinikum Essen, Essen, Germany.,Servei de Física i Protecció Radiològica, Hospital Universitari Vall d'Hebron, Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Lorenzo Brualla
- NCTeam, Strahlenklinik, Universitätsklinikum Essen, Essen, Germany
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28
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Jaccard M, Durán MT, Petersson K, Germond JF, Liger P, Vozenin MC, Bourhis J, Bochud F, Bailat C. High dose-per-pulse electron beam dosimetry: Commissioning of the Oriatron eRT6 prototype linear accelerator for preclinical use. Med Phys 2018; 45:863-874. [DOI: 10.1002/mp.12713] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 09/13/2017] [Accepted: 11/15/2017] [Indexed: 11/10/2022] Open
Affiliation(s)
- Maud Jaccard
- Institute of Radiation Physics; Lausanne University Hospital; Lausanne Switzerland
| | - Maria Teresa Durán
- Institute of Radiation Physics; Lausanne University Hospital; Lausanne Switzerland
| | - Kristoffer Petersson
- Institute of Radiation Physics; Lausanne University Hospital; Lausanne Switzerland
| | | | | | - Marie-Catherine Vozenin
- Department of Radiation Oncology; Lausanne University Hospital; Lausanne Switzerland
- Radio-Oncology Laboratory; DO/CHUV; Lausanne University Hospital; Lausanne Switzerland
| | - Jean Bourhis
- Department of Radiation Oncology; Lausanne University Hospital; Lausanne Switzerland
- Radio-Oncology Laboratory; DO/CHUV; Lausanne University Hospital; Lausanne Switzerland
| | - François Bochud
- Institute of Radiation Physics; Lausanne University Hospital; Lausanne Switzerland
| | - Claude Bailat
- Institute of Radiation Physics; Lausanne University Hospital; Lausanne Switzerland
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29
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Niemelä J, Partanen M, Ojala J, Sipilä P, Björkqvist M, Kapanen M, Keyriläinen J. Measurement and properties of the dose–area product ratio in external small-beam radiotherapy. Phys Med Biol 2017; 62:4870-4883. [DOI: 10.1088/1361-6560/aa6861] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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30
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Jaccard M, Petersson K, Buchillier T, Germond JF, Durán MT, Vozenin MC, Bourhis J, Bochud FO, Bailat C. High dose-per-pulse electron beam dosimetry: Usability and dose-rate independence of EBT3 Gafchromic films. Med Phys 2017; 44:725-735. [PMID: 28019660 DOI: 10.1002/mp.12066] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 12/02/2016] [Accepted: 12/07/2016] [Indexed: 11/09/2022] Open
Abstract
PURPOSE The aim of this study was to assess the suitability of Gafchromic EBT3 films for reference dose measurements in the beam of a prototype high dose-per-pulse linear accelerator (linac), capable of delivering electron beams with a mean dose-rate (Ḋm ) ranging from 0.07 to 3000 Gy/s and a dose-rate in pulse (Ḋp ) of up to 8 × 106 Gy/s. To do this, we evaluated the overall uncertainties in EBT3 film dosimetry as well as the energy and dose-rate dependence of their response. MATERIAL AND METHODS Our dosimetric system was composed of EBT3 Gafchromic films in combination with a flatbed scanner and was calibrated against an ionization chamber traceable to primary standard. All sources of uncertainties in EBT3 dosimetry were carefully analyzed using irradiations at a clinical radiotherapy linac. Energy dependence was investigated with the same machine by acquiring and comparing calibration curves for three different beam energies (4, 8 and 12 MeV), for doses between 0.25 and 30 Gy. Ḋm dependence was studied at the clinical linac by changing the pulse repetition frequency (f) of the beam in order to vary Ḋm between 0.55 and 4.40 Gy/min, while Ḋp dependence was probed at the prototype machine for Ḋp ranging from 7 × 103 to 8 × 106 Gy/s. Ḋp dependence was first determined by studying the correlation between the dose measured by films and the charge of electrons measured at the exit of the machine by an induction torus. Furthermore, we compared doses from the films to independently calibrated thermo-luminescent dosimeters (TLD) that have been reported as being dose-rate independent up to such high dose-rates. RESULTS We report that uncertainty below 4% (k = 2) can be achieved in the dose range between 3 and 17 Gy. Results also demonstrated that EBT3 films did not display any detectable energy dependence for electron beam energies between 4 and 12 MeV. No Ḋm dependence was found either. In addition, we obtained excellent consistency between films and TLDs over the entire Ḋp range attainable at the prototype linac confirming the absence of any dose-rate dependence within the investigated range (7 × 103 to 8 × 106 Gy/s). This aspect was further corroborated by the linear relationship between the dose-per-pulse (Dp ) measured by films and the charge per pulse (Cp ) measured at the prototype linac exit. CONCLUSION Our study shows that the use of EBT3 Gafchromic films can be extended to reference dosimetry in pulsed electron beams with a very high dose rate. The measurement results are associated with an overall uncertainty below 4% (k = 2) and are dose-rate and energy independent.
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Affiliation(s)
- Maud Jaccard
- Institute of Radiation Physics (IRA), Lausanne University Hospital, Lausanne, Switzerland
| | - Kristoffer Petersson
- Institute of Radiation Physics (IRA), Lausanne University Hospital, Lausanne, Switzerland
| | - Thierry Buchillier
- Institute of Radiation Physics (IRA), Lausanne University Hospital, Lausanne, Switzerland
| | - Jean-François Germond
- Institute of Radiation Physics (IRA), Lausanne University Hospital, Lausanne, Switzerland
| | - Maria Teresa Durán
- Institute of Radiation Physics (IRA), Lausanne University Hospital, Lausanne, Switzerland
| | - Marie-Catherine Vozenin
- Department of Radiation Oncology, Lausanne University Hospital, Lausanne, Switzerland.,Radio-Oncology Laboratory, DO/CHUV, Lausanne University Hospital Lausanne, Lausanne, Switzerland
| | - Jean Bourhis
- Department of Radiation Oncology, Lausanne University Hospital, Lausanne, Switzerland.,Radio-Oncology Laboratory, DO/CHUV, Lausanne University Hospital Lausanne, Lausanne, Switzerland
| | - François O Bochud
- Institute of Radiation Physics (IRA), Lausanne University Hospital, Lausanne, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics (IRA), Lausanne University Hospital, Lausanne, Switzerland
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31
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Zeverino M, Jaccard M, Patin D, Ryckx N, Marguet M, Tuleasca C, Schiappacasse L, Bourhis J, Levivier M, Bochud FO, Moeckli R. Commissioning of the Leksell Gamma Knife®
Icon™. Med Phys 2017; 44:355-363. [DOI: 10.1002/mp.12052] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 11/29/2016] [Accepted: 12/01/2016] [Indexed: 01/08/2023] Open
Affiliation(s)
- Michele Zeverino
- Institute of Radiation Physics; Lausanne University Hospital; Lausanne Switzerland
| | - Maud Jaccard
- Institute of Radiation Physics; Lausanne University Hospital; Lausanne Switzerland
| | - David Patin
- Institute of Radiation Physics; Lausanne University Hospital; Lausanne Switzerland
| | - Nick Ryckx
- Institute of Radiation Physics; Lausanne University Hospital; Lausanne Switzerland
| | - Maud Marguet
- Institute of Radiation Physics; Lausanne University Hospital; Lausanne Switzerland
| | - Constantin Tuleasca
- Department of Neurosurgery and Gamma Knife Center; Lausanne University Hospital; Lausanne Switzerland
| | - Luis Schiappacasse
- Department of Radiation Oncology; Lausanne University Hospital; Lausanne Switzerland
| | - Jean Bourhis
- Department of Radiation Oncology; Lausanne University Hospital; Lausanne Switzerland
| | - Marc Levivier
- Department of Neurosurgery and Gamma Knife Center; Lausanne University Hospital; Lausanne Switzerland
| | - Francois O. 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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