1
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Episkopakis A, Margaroni V, Kanellopoulou S, Marinos N, Koutsouveli E, Karaiskos P, Pappas EP. Dose-response dependencies of OSL dosimeters in conventional linacs and 1.5T MR-linacs: an experimental and Monte Carlo study. Phys Med Biol 2023; 68:225002. [PMID: 37857285 DOI: 10.1088/1361-6560/ad051e] [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: 08/13/2023] [Accepted: 10/19/2023] [Indexed: 10/21/2023]
Abstract
Objective. This work focuses on the optically stimulated luminescence dosimetry (OSLD) dose-response characterization, with emphasis on 1.5T MR-Linacs.Approach. Throughout this study, the nanoDots OSLDs (Landauer, USA) were considered. In groups of three, the mean OSLD response was measured in a conventional linac and an MR-Linac under various irradiation conditions to investigate (i) dose-response linearity with and without the 1.5T magnetic field, (ii) signal fading rate and its dependencies, (iii) beam quality, detector orientation and dose rate dependencies in a conventional linac, (iii) potential MR imaging related effects on OSLD response and (iv) detector orientation dependence in an MR-Linac. Monte Carlo calculations were performed to further quantify angular dependence after rotating the detector around its central axis parallel to the magnetic field, and determine the magnetic field correction factors,kB,Q,for all cardinal detector orientations.Main results. OSLD dose-response supralinearity in an MR-Linac setting was found to agree within uncertainties with the corresponding one in a conventional linac, for the axial detector orientation investigated. Signal fading rate does not depend on irradiation conditions for the range of 3-30 d considered. OSLD angular (orientation) dependence is more pronounced under the presence of a magnetic field. OSLDs irradiated with and without real-time T2w MR imaging enabled during irradiation yielded the same response within uncertainties.kB,Qvalues were determined for all three cardinal orientations. Corrections needed reached up to 6.4%. However, if OSLDs are calibrated in the axial orientation and then irradiated in an MR-Linac placed again in the axial orientation (perpendicular to the magnetic field), then simulations suggest thatkB,Qcan be considered unity within uncertainties, irrespective of the incident beam angle.Significance. This work contributes towards OSLD dose-response characterization and relevant correction factors availability. OSLDs are suitable for QA checks in MR-based beam gating applications andin vivodosimetry in MR-Linacs.
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Affiliation(s)
- Anastasios Episkopakis
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, 75 Mikras Asias, 115 27 Athens, Greece
- Global Clinical Operations, Elekta Ltd., Fleming way, RH10 99RR Crawley, West Sussex, United Kingdom
| | - Vasiliki Margaroni
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, 75 Mikras Asias, 115 27 Athens, Greece
| | | | - Nikolas Marinos
- Global Clinical Operations, Elekta Ltd., Fleming way, RH10 99RR Crawley, West Sussex, United Kingdom
| | - Efi Koutsouveli
- Medical Physics Department, Hygeia Hospital, Kifissias Avenue & 4 Erythrou Stavrou, Marousi, 151 23 Athens, Greece
| | - Pantelis Karaiskos
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, 75 Mikras Asias, 115 27 Athens, Greece
| | - Eleftherios P Pappas
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, 75 Mikras Asias, 115 27 Athens, Greece
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2
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Dimitriadis A, Kazantsev P, Chelminski K, Titovich E, Naida E, Magnus T, Meghzifene A, Azangwe G, Carrara M, Swamidas J. IAEA/WHO postal dosimetry audit methodology for electron beams using radio photoluminescent dosimeters. Med Phys 2023; 50:7214-7221. [PMID: 37793099 DOI: 10.1002/mp.16776] [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: 03/29/2023] [Revised: 06/02/2023] [Accepted: 09/23/2023] [Indexed: 10/06/2023] Open
Abstract
BACKGROUND Independent dosimetry audits are an important intervention in radiotherapy for quality assurance. Electron beams, used for superficial radiotherapy treatments, must also be tested in dosimetry audits as part of a good quality assurance program to help prevent clinical errors. PURPOSE To establish a new service for IAEA/WHO postal dosimetry audits in electron beams using RPL dosimeters. METHODS A novel postal audit methodology employing a PMMA holder system for RPLDs was developed. The associated correction factors including holder dependence, energy dependence, dose response non-linearity, and fading were obtained and tested in a multi-center (n = 12) pilot study. A measurement uncertainty budget was estimated and employed in analyzing the irradiated dosimeters. RESULTS Holder and energy correction factors ranged from 1.004 to 1.010 and 1.019 to 1.059 respectively across the energy range. The non-linearity and fading correction models used for photon beams were tested in electron beams and did not significantly increase measurement uncertainty. The mean dose ratio ± SD of the multi-center study was 1.001 ± 0.011. The overall uncertainty budget was estimated as ± 1.42% (k = 1). CONCLUSIONS A methodology for IAEA/WHO postal dosimetry audits in electron beams was developed and validated in a multi-center study and is now made available to radiotherapy centers as a routine service.
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Affiliation(s)
- Alexis Dimitriadis
- Dosimetry and Medical Radiation Physics Section, Division of Human Health, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna, Austria
| | - Pavel Kazantsev
- Dosimetry and Medical Radiation Physics Section, Division of Human Health, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna, Austria
| | - Krzysztof Chelminski
- Dosimetry and Medical Radiation Physics Section, Division of Human Health, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna, Austria
| | - Egor Titovich
- Dosimetry and Medical Radiation Physics Section, Division of Human Health, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna, Austria
| | - Ekaterina Naida
- Dosimetry and Medical Radiation Physics Section, Division of Human Health, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna, Austria
| | - Talent Magnus
- Dosimetry and Medical Radiation Physics Section, Division of Human Health, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna, Austria
| | - Ahmed Meghzifene
- Dosimetry and Medical Radiation Physics Section, Division of Human Health, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna, Austria
| | - Godfrey Azangwe
- Dosimetry and Medical Radiation Physics Section, Division of Human Health, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna, Austria
| | - Mauro Carrara
- Dosimetry and Medical Radiation Physics Section, Division of Human Health, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna, Austria
| | - Jamema Swamidas
- Dosimetry and Medical Radiation Physics Section, Division of Human Health, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna, Austria
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3
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Yedekci Y, Elmalı A, Demirkiran G, Ozyigit G, Yazici G. Transit dosimetry of stereotactic body radiotherapy treatments with electronic portal dosimetry device in patient with spinal implant. Phys Eng Sci Med 2022; 45:1103-1109. [PMID: 36074299 DOI: 10.1007/s13246-022-01177-5] [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: 03/30/2022] [Accepted: 08/30/2022] [Indexed: 12/15/2022]
Abstract
In recent years, the use of the Electronic Portal Imaging Device (EPID) as an in vivo dosimeter has become widespread. However, reports of EPID for stereotactic body radiotherapy (SBRT) applications is scarce. There is no data on this topic especially when there are high-density materials in the radiation field. In this study, we aimed to investigate the dose distributions of SBRT treatment plans in patients with spinal implants by transit EPID dosimetry. Implants were inserted in phantoms that mimic the vertebrae, and VMAT plans were created on the phantoms to deliver 16 Gy radiation doses to the target in 1 fraction. Transit EPID measurements were performed for each irradiation. The results were compared with the treatment planning system using the gamma analysis method. According to the gamma analysis results, while the non-implant model met the acceptance criteria with a rate of 95.4%, the implanted models did not pass the test with results between the rates of 70% to 73%. In addition, while the dose difference in the isocenter was 1.3% for the non-implanted model, this difference was observed to be between 7 and 8% in the implanted models. Our study revealed that EPID can be used as transit dosimetry for the VMAT-SBRT applications. However, unacceptable dose differences were obtained by transit EPID dosimetry in the VMAT-SBRT applications of patients with an implant. In the treatment of such patients, alternative treatment methods should be preferred in which the interaction of the implants with radiation can be prevented.
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Affiliation(s)
- Yagiz Yedekci
- Department of Radiation Oncology, Faculty of Medicine, Hacettepe University, 06100, Sihhiye, Ankara, Turkey.
| | - Aysenur Elmalı
- Department of Radiation Oncology, Faculty of Medicine, Hacettepe University, 06100, Sihhiye, Ankara, Turkey
| | - Gökhan Demirkiran
- Department of Orthopaedics and Traumatology, Faculty of Medicine, Hacettepe University, Sihhiye, Ankara, Turkey
| | - Gokhan Ozyigit
- Department of Radiation Oncology, Faculty of Medicine, Hacettepe University, 06100, Sihhiye, Ankara, Turkey
| | - Gözde Yazici
- Department of Radiation Oncology, Faculty of Medicine, Hacettepe University, 06100, Sihhiye, Ankara, Turkey
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4
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Goto S, Hayashi H, Yamaguchi H, Sekiguchi H, Akino R, Shimizu M. Signal-stabilized Al2O3:C-OSL dosimeter “checking chip” for correcting OSL reader sensitivity variation. RADIAT MEAS 2022. [DOI: 10.1016/j.radmeas.2022.106893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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5
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Villani D, Faria K, Kauark-Fontes E, Ribeiro C, Mascarenhas Y, Ribeiro A, Vechiato-Filho A, Menegussi G, Vasconcelos K, Santos-Silva A, Brandão T. Protocol determination for OSL in vivo measurements of absorbed dose in the oral mucosa in oral cancer patients: A pilot study. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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6
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Abdullah N, Bradley D, Nisbet A, Kamarul Zaman Z, Deraman S, Mohd Noor N. Dosimetric characteristics of fabricated germanium doped optical fibres for a postal audit of therapy electron beams. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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7
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Lehmann J, Hussein M, Barry M, Siva S, Moore A, Chu M, Díez P, Eaton DJ, Harwood J, Lonski P, Claridge Mackonis E, Meehan C, Patel R, Ray X, Shaw M, Shepherd J, Smyth G, Standen TS, Subramanian B, Greer P, Clark CH. SEAFARER – A new concept for validating radiotherapy patient specific QA for clinical trials and clinical practice. Radiother Oncol 2022; 171:121-128. [DOI: 10.1016/j.radonc.2022.04.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 03/22/2022] [Accepted: 04/14/2022] [Indexed: 01/12/2023]
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8
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Kron T, Fox C, Ebert MA, Thwaites D. Quality management in radiotherapy treatment delivery. J Med Imaging Radiat Oncol 2022; 66:279-290. [PMID: 35243785 DOI: 10.1111/1754-9485.13348] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 10/29/2021] [Indexed: 12/17/2022]
Abstract
Radiation Oncology continues to rely on accurate delivery of radiation, in particular where patients can benefit from more modulated and hypofractioned treatments that can deliver higher dose to the target while optimising dose to normal structures. These deliveries are more complex, and the treatment units are more computerised, leading to a re-evaluation of quality assurance (QA) to test a larger range of options with more stringent criteria without becoming too time and resource consuming. This review explores how modern approaches of risk management and automation can be used to develop and maintain an effective and efficient QA programme. It considers various tools to control and guide radiation delivery including image guidance and motion management. Links with typical maintenance and repair activities are discussed, as well as patient-specific quality control activities. It is demonstrated that a quality management programme applied to treatment delivery can have an impact on individual patients but also on the quality of treatment techniques and future planning. Developing and customising a QA programme for treatment delivery is an important part of radiotherapy. Using modern multidisciplinary approaches can make this also a useful tool for department management.
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Affiliation(s)
- Tomas Kron
- Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.,Sir Peter MacCallum Institute of Oncology, Melbourne University, Melbourne, Victoria, Australia.,Centre for Medical Radiation Physics, University of Wollongong, Wollongong, New South Wales, Australia
| | - Chris Fox
- Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
| | - Martin A Ebert
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, New South Wales, Australia.,Department of Radiation Oncology, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia.,School of Physics, Mathematics and Computing, University of Western Australia, Perth, Western Australia, Australia.,5D Clinics, Perth, Western Australia, Australia
| | - David Thwaites
- Institute of Medical Physics, School of Physics, University of Sydney, Sydney, New South Wales, Australia.,Medical Physics Group, Leeds Institute of Cardiovascular and Metabolic Medicine and Leeds Institute of Medical Research, University of Leeds, Leeds, UK
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9
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Yukihara E, Christensen J, Togno M. Demonstration of an optically stimulated luminescence (OSL) material with reduced quenching for proton therapy dosimetry: MgB4O7:Ce,Li. RADIAT MEAS 2022. [DOI: 10.1016/j.radmeas.2022.106721] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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10
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Merkis M, Puišo J, Adliene D, Laurikaitiene J. Development and Characterization of Silver Containing Free Standing Polymer FILMS for Dosimetry Applications. Polymers (Basel) 2021; 13:polym13223925. [PMID: 34833224 PMCID: PMC8623515 DOI: 10.3390/polym13223925] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 11/05/2021] [Accepted: 11/08/2021] [Indexed: 12/04/2022] Open
Abstract
Polymer gels and films, due to their near equivalence to biological tissue, are amongst the most promising future dosimetry tools for medical applications. The application of polymer dose gels is limited by the sensitivity of dose readout methods and dose gel properties. It is a challenge to find suitable dosimeters for registration of doses delivered to the target by orthovoltage therapy units. The application of metal-particle-enriched polymer composites for dose registration in X-ray therapy might be an elegant solution, especially if recent dose-reading technologies exploring advantages of different physical phenomena are involved. In this work, X-rays from the orthovoltage therapy range were used for the irradiation of experimental samples. In addition, radiation-induced processes of formation of silver nanoparticles in AgNO3–PVA gels and in free standing AgNO3PVA films, also containing some additional solvents, namely glycerol, ethanol, and isopropanol, have been investigated, with the aim to apply the developed composites for medical dosimetry purposes. A simple and environmentally friendly method for the formation of free-standing AgPVA films at room temperature was proposed and realized for preparing AgPVA films for investigation. Radiation-induced synthesis of silver nanoparticles in AgPVA composites was investigated, analyzing LPSR-based UV-VIS spectral changes to the irradiated films with respect to irradiation doses, and dose-related tendencies were also evaluated. It was shown that AgPVA films were more sensitive for detection of doses from the interval 0–1.0 Gy, thus indicating potential application of AgPVA films for dosimetry purposes.
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Affiliation(s)
| | - Judita Puišo
- Correspondence: (J.P.); (D.A.); Tel.: +370-61004812 (J.P.)
| | - Diana Adliene
- Correspondence: (J.P.); (D.A.); Tel.: +370-61004812 (J.P.)
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11
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Hughes J, Lye JE, Kadeer F, Alves A, Shaw M, Supple J, Keehan S, Gibbons F, Lehmann J, Kron T. Calculation algorithms and penumbra: Underestimation of dose in organs at risk in dosimetry audits. Med Phys 2021; 48:6184-6197. [PMID: 34287963 DOI: 10.1002/mp.15123] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 06/27/2021] [Accepted: 07/07/2021] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The aim of this study is to investigate overdose to organs at risk (OARs) observed in dosimetry audits in Monte Carlo (MC) algorithms and Linear Boltzmann Transport Equation (LBTE) algorithms. The impact of penumbra modeling on OAR dose was assessed with the adjustment of MC modeling parameters and the clinical relevance of the audit cases was explored with a planning study of spine and head and neck (H&N) patient cases. METHODS Dosimetric audits performed by the Australian Clinical Dosimetry Service (ACDS) of 43 anthropomorphic spine plans and 1318 C-shaped target plans compared the planned dose to doses measured with ion chamber, microdiamond, film, and ion chamber array. An MC EGSnrc model was created to simulate the C-shape target case. The electron cut-off energy Ecut(kinetic) was set at 500, 200, and 10 keV, and differences between 1 and 3 mm voxel were calculated. A planning study with 10 patient stereotactic body radiotherapy (SBRT) spine plans and 10 patient H&N plans was calculated in both Acuros XB (AXB) v15.6.06 and Anisotropic Analytical Algorithm (AAA) v15.6.06. The patient contour was overridden to water as only the penumbral differences between the two different algorithms were under investigation. RESULTS The dosimetry audit results show that for the SBRT spine case, plans calculated in AXB are colder than what is measured in the spinal cord by 5%-10%. This was also observed for other audit cases where a C-shape target is wrapped around an OAR where the plans were colder by 3%-10%. Plans calculated with Monaco MC were colder than measurements by approximately 7% with the OAR surround by a C-shape target, but these differences were not noted in the SBRT spine case. Results from the clinical patient plans showed that the AXB was on average 7.4% colder than AAA when comparing the minimum dose in the spinal cord OAR. This average difference between AXB and AAA reduced to 4.5% when using the more clinically relevant metric of maximum dose in the spinal cord. For the H&N plans, AXB was cooler on average than AAA in the spinal cord OAR (1.1%), left parotid (1.7%), and right parotid (2.3%). The EGSnrc investigation also noted similar, but smaller differences. The beam penumbra modeled by Ecut(kinetic) = 500 keV was steeper than the beam penumbra modeled by Ecut(kinetic) = 10 keV as the full scatter is not accounted for, which resulted in less dose being calculated in a central OAR region where the penumbra contributes much of the dose. The dose difference when using 2.5 mm voxels of the center of the OAR between 500 and 10 keV was 3%, reducing to 1% between 200 and 10 keV. CONCLUSIONS Lack of full penumbral modeling due to approximations in the algorithms in MC based or LBTE algorithms are a contributing factor as to why these algorithms under-predict the dose to OAR when the treatment volume is wrapped around the OAR. The penumbra modeling approximations also contribute to AXB plans predicting colder doses than AAA in areas that are in the vicinity of beam penumbra. This effect is magnified in regions where there are many beam penumbras, for example in the spinal cord for spine SBRT cases.
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Affiliation(s)
- Jeremy Hughes
- Australian Clinical Dosimetry Service, ARPANSA, Yallambie, Victoria, Australia.,Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
| | - Jessica Elizabeth Lye
- Australian Clinical Dosimetry Service, ARPANSA, Yallambie, Victoria, Australia.,Physical Sciences, Olivia Newton-John Cancer Wellness Centre, Heidelberg, Victoria, Australia
| | - Fayz Kadeer
- Australian Clinical Dosimetry Service, ARPANSA, Yallambie, Victoria, Australia
| | - Andrew Alves
- Australian Clinical Dosimetry Service, ARPANSA, Yallambie, Victoria, Australia
| | - Maddison Shaw
- Australian Clinical Dosimetry Service, ARPANSA, Yallambie, Victoria, Australia.,Applied Sciences Physics Department, RMIT University, Melbourne, Victoria, Australia
| | - Jeremy Supple
- Australian Clinical Dosimetry Service, ARPANSA, Yallambie, Victoria, Australia
| | - Stephanie Keehan
- Australian Clinical Dosimetry Service, ARPANSA, Yallambie, Victoria, Australia.,Alfred Health Radiation Oncology, The Alfred Hospital, Melbourne, Victoria, Australia
| | - Francis Gibbons
- Australian Clinical Dosimetry Service, ARPANSA, Yallambie, Victoria, Australia.,Physical Sciences, Sunshine Coast University Hospital, Birtinya, Queensland, Australia
| | - Joerg Lehmann
- Applied Sciences Physics Department, RMIT University, Melbourne, Victoria, Australia.,Department of Radiation Oncology, Calvary Mater Newcastle, Newcastle, New South Wales, Australia.,School of Mathematical and Physical Sciences, University of Newcastle, Callaghan, New South Wales, Australia.,Institute of Medical Physics, University of Sydney, Camperdown, New South Wales, Australia
| | - Tomas Kron
- Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.,Applied Sciences Physics Department, RMIT University, Melbourne, Victoria, Australia
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12
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Araki F. Monte Carlo determination of a nanoDot OSLD response using quality index for diagnostic kilovoltage X-ray beams. Phys Med 2021; 84:101-108. [PMID: 33887616 DOI: 10.1016/j.ejmp.2021.03.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/22/2021] [Accepted: 03/29/2021] [Indexed: 11/17/2022] Open
Abstract
PURPOSE This study aims to investigate the energy response of an optically stimulated luminescent dosimeter known as nanoDot for diagnostic kilovoltage X-ray beams via Monte Carlo calculations. METHODS The nanoDot response is calculated as a function of X-ray beam quality in free air and on a water phantom surface using Monte Carlo simulations. The X-ray fluence spectra are classified using the quality index (QI), which is defined as the ratio of the effective energy to the maximum energy of the photons. The response is calculated for X-ray fluence spectra with QIs of 0.4, 0.5, and 0.6 with tube voltages of 50-137.6 kVp and monoenergetic photon beams. The surface dose estimated using the calculated response is verified by comparing it with that measured using an ionization chamber. RESULTS The nanoDot response in free air for monoenergetic photon beams (QI = 1.0) varies significantly at photon energies below 100 keV and reaches a factor of 3.6 at 25-30 keV. The response differs by up to approximately 6% between QIs of 0.4 and 0.6 for the same half-value layer (HVL). The response at the phantom surface decreases slightly owing to the backscatter effect, and it is almost independent of the field size. The agreement between the surface dose estimated using the nanoDot and that measured using the ionization chamber for assessing X-ray beam qualities is less than 2%. CONCLUSIONS The nanoDot response is indicated as a function of HVL for the specified QIs, and it enables the direct surface dose measurement.
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Affiliation(s)
- Fujio Araki
- Department of Health Sciences, Faculty of Life Sciences, Kumamoto University, 4-24-1 Kuhonji, Chuo-ku, Kumamoto 862-0976, Japan.
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13
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Christensen JB, Togno M, Nesteruk KP, Psoroulas S, Meer D, Weber DC, Lomax T, Yukihara EG, Safai S. Al 2O 3:C optically stimulated luminescence dosimeters (OSLDs) for ultra-high dose rate proton dosimetry. Phys Med Biol 2021; 66. [PMID: 33571973 DOI: 10.1088/1361-6560/abe554] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 02/11/2021] [Indexed: 11/11/2022]
Abstract
The response of Al2O3:C optically stimulated luminescence detectors (OSLDs) was investigated in a 250 MeV pencil proton beam. The OSLD response was mapped for a wide range of average dose rates up to 9000 Gy s-1, corresponding to a ∼150 kGy s-1instantaneous dose rate in each pulse. Two setups for ultra-high dose rate (FLASH) experiments are presented, which enable OSLDs or biological samples to be irradiated in either water-filled vials or cylinders. The OSLDs were found to be dose rate independent for all dose rates, with an average deviation <1% relative to the nominal dose for average dose rates of (1-1000) Gy s-1when irradiated in the two setups. A third setup for irradiations in a 9000 Gy s-1pencil beam is presented, where OSLDs are distributed in a 3 × 4 grid. Calculations of the signal averaging of the beam over the OSLDs were in agreement with the measured response at 9000 Gy s-1. Furthermore, a new method was presented to extract the beam spot size of narrow pencil beams, which is in agreement within a standard deviation with results derived from radiochromic films. The Al2O3:C OSLDs were found applicable to support radiobiological experiments in proton beams at ultra-high dose rates.
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Affiliation(s)
| | - Michele Togno
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland
| | | | | | - David Meer
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland
| | - Damien Charles Weber
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland.,Department of Radiation Oncology, University Hospital Zurich, Switzerland.,Department of Radiation Oncology, University Hospital Bern, Switzerland
| | - Tony Lomax
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland.,Department of Physics, ETH Zurich, Switzerland
| | - Eduardo G Yukihara
- Department of Radiation Safety and Security, Paul Scherrer Institute, Switzerland
| | - Sairos Safai
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland
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14
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Yukihara EG, Kron T. APPLICATIONS OF OPTICALLY STIMULATED LUMINESCENCE IN MEDICAL DOSIMETRY. RADIATION PROTECTION DOSIMETRY 2020; 192:122-138. [PMID: 33412585 DOI: 10.1093/rpd/ncaa213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 11/15/2020] [Accepted: 11/23/2020] [Indexed: 06/12/2023]
Abstract
If the first decade of the new millennium saw the establishment of a more solid foundation for the use of the Optically Stimulated Luminescence (OSL) in medical dosimetry, the second decade saw the technique take root and become more widely used in clinical studies. Recent publications report not only characterization and feasibility studies of the OSL technique for various applications in radiotherapy and radiology, but also the practical use of OSL for postal audits, estimation of staff dose, in vivo dosimetry, dose verification and dose mapping studies. This review complements previous review papers and reports on the topic, providing a panorama of the new advances and applications in the last decade. Attention is also dedicated to potential future applications, such as LET dosimetry, 2D/3D dosimetry using OSL, dosimetry in magnetic resonance imaging-guided radiotherapy (MRIgRT) and dosimetry of extremely high dose rates (FLASH therapy).
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Affiliation(s)
- Eduardo G Yukihara
- Department of Radiation Safety and Security, Paul Scherrer Institute, 5200 Villigen, Switzerland
| | - Tomas Kron
- Department of Physical Sciences, Peter MacCallum Cancer Centre, 3000 Melbourne, Australia
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15
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Ito S, Araki F, Hoshida K, Ohno T. Impact of transverse magnetic fields on dose response of a nanoDot OSLD in megavoltage photon beams. Phys Med 2020; 70:153-160. [PMID: 32028172 DOI: 10.1016/j.ejmp.2020.01.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 01/24/2020] [Accepted: 01/26/2020] [Indexed: 10/25/2022] Open
Abstract
PURPOSE We investigated the impact of transverse magnetic fields on the dose response of a nanoDot optically stimulated luminescence dosimetry (OSLD) in megavoltage photon beams. METHODS The nanoDot OSLD response was calculated via Monte Carlo (MC) simulations. The responses RQ and RQ,B without and with the transverse magnetic fields of 0.35-3 T were analyzed as a function of depth at a 10 cm × 10 cm field for 4-18 MV photons in a solid water phantom. All responses were determined based on comparisons with the response under the reference conditions (depth of 10 cm and a 10 cm × 10 cm field) for 6 MV without the magnetic field. In addition, the influence of air-gaps on the nanoDot response in the magnetic field was estimated according to Burlin's general cavity theory. RESULTS The RQ as a function of depth for 4-18 MV ranged from 1.013 to 0.993, excepting the buildup region. The RQ,B increased from 2.8% to 1.5% at 1.5 T and decreased from 3.0% to 1.1% at 3 T in comparison with RQ as the photon energy increased. The depth dependence of RQ,B was less than 1%, excepting the buildup region. The top air-gap and the bottom air- gap were responsible for the response reduction and the response increase, respectively. CONCLUSIONS The response RQ,B varied depending on the magnetic field intensity, and the variation of RQ,B reduced as the photon beam energy increased. The air-gaps affected the dose deposition in the magnetic fields.
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Affiliation(s)
- Shotaro Ito
- Graduate School of Health Sciences, Kumamoto University, 4-24-1 Kuhonji, Kumamoto, Japan
| | - Fujio Araki
- Department of Health Sciences, Faculty of Life Sciences, Kumamoto University, 4-24-1 Kuhonji, Kumamoto, Japan.
| | - Kento Hoshida
- Graduate School of Health Sciences, Kumamoto University, 4-24-1 Kuhonji, Kumamoto, Japan
| | - Takeshi Ohno
- Department of Health Sciences, Faculty of Life Sciences, Kumamoto University, 4-24-1 Kuhonji, Kumamoto, Japan
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In vivo monitoring of total skin electron dose using optically stimulated luminescence dosimeters. Rep Pract Oncol Radiother 2020; 25:35-40. [PMID: 31889918 DOI: 10.1016/j.rpor.2019.12.011] [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: 07/12/2019] [Revised: 09/23/2019] [Accepted: 12/09/2019] [Indexed: 11/21/2022] Open
Abstract
Aim This study retrospectively analysed the results of using optically stimulated radiation dosimeters (OSLDs) for in vivo dose measurements during total skin electron therapy (TSET, also known as TSEI, TSEB, TSEBT, TSI or TBE) treatments of patients with mycosis fungoides. Background TSET treatments are generally delivered to standing patients, using treatment plans that are devised using manual dose calculations that require verification via in vivo dosimetry. Despite the increasing use of OSLDs for radiation dosimetry, there is minimal published guidance on the use of OSLDs for TSET verification. Materials and methods This study retrospectively reviewed in vivo dose measurements made during treatments of nine consecutive TSET patients, treated between 2013 and 2018. Landauer nanoDot OSLDs were used to measure the skin dose at reference locations on each patient, as well as at locations of clinical interest such as the head, hands, feet, axilla and groin. Results 1301 OSLD measurements were aggregated and analysed, producing results that were in broad agreement with previous TLD studies, while providing additional information about the variation of dose across concave surfaces and potentially guiding future refinement of treatment setup. In many cases these in vivo measurements were used to identify deviations from the planned dose in reference locations and to identify anatomical regions where additional shielding or boost treatments were required. Conclusions OSLDs can be used to obtain measurements of TSET dose that can inform monitor unit adjustments and identify regions of under and over dosage, while potentially informing continuous quality improvement in TSET treatment delivery.
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Hoshida K, Araki F, Ohno T, Kobayashi I. Response of a nanoDot OSLD system in megavoltage photon beams. Phys Med 2019; 64:74-80. [DOI: 10.1016/j.ejmp.2019.06.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 06/16/2019] [Accepted: 06/25/2019] [Indexed: 11/29/2022] Open
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Kron T, Hardcastle N. SABR in clinical trials: what quality assurance (QA) is required and how can it be done? ACTA ACUST UNITED AC 2019. [DOI: 10.1088/1742-6596/1154/1/012014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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19
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Akyol F, Sarigul N, Yeginer M, Yedekci Y, Utku H. Evaluation of NanoDot Optically Stimulated Luminescence Dosimeter for Cone-shaped Small-field Dosimetry of Cyberknife Stereotactic Radiosurgery Unit: A Monte Carlo Simulation and Dosimetric Verification Study. J Med Phys 2019; 44:27-34. [PMID: 30983768 PMCID: PMC6438048 DOI: 10.4103/jmp.jmp_96_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Aim The aim of this study was to investigate the adequacy of nanoDot optically stimulated luminescence (OSL) dosimeter for small field dosimetry before its in vivo applications in CyberKnife SRS unit. Materials and Methods A PTW 60018 SRS Diode, 60019 microDiamond, and Gafchromic EBT3 films were used along with a nanoDot carbon-doped aluminum oxide OSL dosimeter to collect and compare beam data. In addition, the EGSnrc/BEAMnrc code was employed to simulate 6-MV photon beams of CyberKnife SRS system. Results All detectors showed good consistency with each other in output factor measurements for cone sizes of 15 mm or more. The differences were maintained within 3% for these cones. However, OSL output factors showed higher discrepancies compared to those of other detectors for smaller cones wherein the difference reached nearly 40% for cone size of 5 mm. Depending on the performance of OSL dosimeter in terms of output factors, percentage depth doses (PDDs) were only measured for cones equal to or larger than 15 mm. The differences in PDD measurements were within 5% for depths in the range of 5-200 mm. Conclusion Its low reliable readings for cones smaller than 15 mm should be considered before its in vivo applications of Cyberknife system.
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Affiliation(s)
- Fadil Akyol
- Department of Radiation Oncology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Neslihan Sarigul
- Institute of Nuclear Science, Hacettepe University, Ankara, Turkey
| | - Mete Yeginer
- Department of Radiation Oncology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Yagiz Yedekci
- Department of Radiation Oncology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Haluk Utku
- Institute of Nuclear Science, Hacettepe University, Ankara, Turkey
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Kry SF, Peterson CB, Howell RM, Izewska J, Lye J, Clark CH, Nakamura M, Hurkmans C, Alvarez P, Alves A, Bokulic T, Followill D, Kazantsev P, Lowenstein J, Molineu A, Palmer J, Smith SA, Taylor P, Wesolowska P, Williams I. Remote beam output audits: a global assessment of results out of tolerance. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2018; 7:39-44. [PMID: 31872085 PMCID: PMC6927685 DOI: 10.1016/j.phro.2018.08.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Background and purpose Remote beam output audits, which independently measure an institution’s machine calibration, are a common component of independent radiotherapy peer review. This work reviews the results and trends of these audit results across several organisations and geographical regions. Materials and methods Beam output audit results from the Australian Clinical Dosimetry Services, International Atomic Energy Agency, Imaging and Radiation Oncology Core, and Radiation Dosimetry Services were evaluated from 2010 to the present. The rate of audit results outside a ±5% tolerance was evaluated for photon and electron beams as a function of the year of irradiation and nominal beam energy. Additionally, examples of confirmed calibration errors were examined to provide guidance to clinical physicists and auditing bodies. Results Of the 210,167 audit results, 1323 (0.63%) were outside of tolerance. There was a clear trend of improved audit performance for more recent dates, and while all photon energies generally showed uniform rates of results out of tolerance, low (6 MeV) and high (≥18 MeV) energy electron beams showed significantly elevated rates. Twenty nine confirmed calibration errors were explored and attributed to a range of issues, such as equipment failures, errors in setup, and errors in performing the clinical reference calibration. Forty-two percent of these confirmed errors were detected during ongoing periodic monitoring, and not at the time of the first audit of the machine. Conclusions Remote beam output audits have identified, and continue to identify, numerous and often substantial beam calibration errors.
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Affiliation(s)
- Stephen F Kry
- Imaging and Radiation Oncology Core, MD Anderson Cancer Center, Houston USA.,Department of Radiation Physics, MD Anderson Cancer Center, Houston USA
| | | | - Rebecca M Howell
- Department of Radiation Physics, MD Anderson Cancer Center, Houston USA.,Radiation Dosimetry Services, MD Anderson Cancer Center, Houston USA
| | - Joanna Izewska
- Dosimetry Laboratory, Dosimetry and Medical Radiation Physics Section, Division of Human Health, International Atomic Energy Agency, Vienna Austria
| | - Jessica Lye
- Australian Clinical Dosimetry Service, ARPANSA, Melbourne, Australia
| | - Catharine H Clark
- RadioTherapy Trials Quality Assurance Group, Mount Vernon Cancer Centre, London UK.,Metrology for Medical Physics, National Physical Laboratory, Teddington UK.,Department of Medical Physics, Royal Surrey County Hospital, Surrey UK
| | - Mitsuhiro Nakamura
- JCOG Division of Medical Physics, Department of Information Technology and Medical Engineering, Human Health Sciences, Graduate School of Medicine, Kyoto University
| | - Coen Hurkmans
- EORTC Radiation Oncology Group, Brussels, Belgium.,Department of radiation Oncology, Catharina Hospital Eindhoven, The Netherlands
| | - Paola Alvarez
- Imaging and Radiation Oncology Core, MD Anderson Cancer Center, Houston USA.,Department of Radiation Physics, MD Anderson Cancer Center, Houston USA
| | - Andrew Alves
- Australian Clinical Dosimetry Service, ARPANSA, Melbourne, Australia
| | - Tomislav Bokulic
- Dosimetry Laboratory, Dosimetry and Medical Radiation Physics Section, Division of Human Health, International Atomic Energy Agency, Vienna Austria
| | - David Followill
- Imaging and Radiation Oncology Core, MD Anderson Cancer Center, Houston USA.,Department of Radiation Physics, MD Anderson Cancer Center, Houston USA
| | - Pavel Kazantsev
- Dosimetry Laboratory, Dosimetry and Medical Radiation Physics Section, Division of Human Health, International Atomic Energy Agency, Vienna Austria
| | - Jessica Lowenstein
- Imaging and Radiation Oncology Core, MD Anderson Cancer Center, Houston USA.,Department of Radiation Physics, MD Anderson Cancer Center, Houston USA
| | - Andrea Molineu
- Imaging and Radiation Oncology Core, MD Anderson Cancer Center, Houston USA.,Department of Radiation Physics, MD Anderson Cancer Center, Houston USA
| | - Jacob Palmer
- Department of Radiation Physics, MD Anderson Cancer Center, Houston USA.,Radiation Dosimetry Services, MD Anderson Cancer Center, Houston USA
| | - Susan A Smith
- Department of Radiation Physics, MD Anderson Cancer Center, Houston USA.,Radiation Dosimetry Services, MD Anderson Cancer Center, Houston USA
| | - Paige Taylor
- Imaging and Radiation Oncology Core, MD Anderson Cancer Center, Houston USA.,Department of Radiation Physics, MD Anderson Cancer Center, Houston USA
| | - Paulina Wesolowska
- Dosimetry Laboratory, Dosimetry and Medical Radiation Physics Section, Division of Human Health, International Atomic Energy Agency, Vienna Austria
| | - Ivan Williams
- Australian Clinical Dosimetry Service, ARPANSA, Melbourne, Australia
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Kairn T, Peet S, Yu L, Crowe S. Long-Term Reliability of Optically Stimulated Luminescence Dosimeters. ACTA ACUST UNITED AC 2018. [DOI: 10.1007/978-981-10-9023-3_103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
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Lehmann J, Alves A, Dunn L, Shaw M, Kenny J, Keehan S, Supple J, Gibbons F, Manktelow S, Oliver C, Kron T, Williams I, Lye J. Dosimetric end-to-end tests in a national audit of 3D conformal radiotherapy. Phys Imaging Radiat Oncol 2018; 6:5-11. [PMID: 33458381 PMCID: PMC7807562 DOI: 10.1016/j.phro.2018.03.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 03/14/2018] [Accepted: 03/14/2018] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Independent dosimetry audits improve quality and safety of radiation therapy. This work reports on design and findings of a comprehensive 3D conformal radiotherapy (3D-CRT) Level III audit. MATERIALS AND METHODS The audit was conducted as onsite audit using an anthropomorphic thorax phantom in an end-to-end test by the Australian Clinical Dosimetry Service (ACDS). Absolute dose point measurements were performed with Farmer-type ionization chambers. The audited treatment plans included open and half blocked fields, wedges and lung inhomogeneities. Audit results were determined as Pass Optimal Level (deviations within 3.3%), Pass Action Level (greater than 3.3% but within 5%) and Out of Tolerance (beyond 5%), as well as Reported Not Scored (RNS). The audit has been performed between July 2012 and January 2018 on 94 occasions, covering approximately 90% of all Australian facilities. RESULTS The audit pass rate was 87% (53% optimal). Fifty recommendations were given, mainly related to planning system commissioning. Dose overestimation behind low density inhomogeneities by the analytical anisotropic algorithm (AAA) was identified across facilities and found to extend to beam setups which resemble a typical breast cancer treatment beam placement. RNS measurements inside lung showed a variation in the opposite direction: AAA under-dosed a target beyond lung and over-dosed the lung upstream and downstream of the target. Results also highlighted shortcomings of some superposition and convolution algorithms in modelling large angle wedges. CONCLUSIONS This audit showed that 3D-CRT dosimetry audits remain relevant and can identify fundamental global and local problems that also affect advanced treatments.
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Affiliation(s)
- Joerg Lehmann
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
- Institute of Medical Physics, School of Physics A28, University of Sydney NSW 2006, Australia
- School of Mathematical and Physical Sciences, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia
- School of Science, Royal Melbourne Institute of Technology (RMIT) University, 124 La Trobe Street, Melbourne, VIC 3000, Australia
| | - Andrew Alves
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
| | - Leon Dunn
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
| | - Maddison Shaw
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
- School of Science, Royal Melbourne Institute of Technology (RMIT) University, 124 La Trobe Street, Melbourne, VIC 3000, Australia
| | - John Kenny
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
| | - Stephanie Keehan
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
- School of Science, Royal Melbourne Institute of Technology (RMIT) University, 124 La Trobe Street, Melbourne, VIC 3000, Australia
| | - Jeremy Supple
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
| | - Francis Gibbons
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
| | - Sophie Manktelow
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
| | - Chris Oliver
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
| | - Tomas Kron
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
- School of Science, Royal Melbourne Institute of Technology (RMIT) University, 124 La Trobe Street, Melbourne, VIC 3000, Australia
- Department of Radiation Oncology, Peter MacCallum Cancer Center, 305 Grattan Street, Melbourne, VIC 3000, Australia
| | - Ivan Williams
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
| | - Jessica Lye
- Australian Clinical Dosimetry Service (ACDS), Australian Radiation Protection and National Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, VIC 3085, Australia
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Wesolowska PE, Cole A, Santos T, Bokulic T, Kazantsev P, Izewska J. Characterization of three solid state dosimetry systems for use in high energy photon dosimetry audits in radiotherapy. RADIAT MEAS 2017. [DOI: 10.1016/j.radmeas.2017.04.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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24
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Thomas RA, Bolt MA, Bass G, Nutbrown R, Chen T, Nisbet A, Clark CH. Radiotherapy reference dose audit in the United Kingdom by the National Physical Laboratory: 20 years of consistency and improvements. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2017. [DOI: 10.1016/j.phro.2017.07.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Sensitivity and stability of optically stimulated luminescence dosimeters with filled deep electron/hole traps under pre-irradiation and bleaching conditions. Phys Med 2017; 38:81-87. [PMID: 28610701 DOI: 10.1016/j.ejmp.2017.05.057] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 03/14/2017] [Accepted: 05/10/2017] [Indexed: 11/20/2022] Open
Abstract
PURPOSE We aimed to evaluate the characteristics of optically stimulated luminescence dosimeters (OSLDs) with fully filled deep electron/hole traps, and determine the optimal bleaching conditions for these OSLDs to minimize the changes in dose sensitivity or linearity according to the accumulated dose. METHODS InLight nanoDots were used as OSLDs. The OSLDs were first pre-irradiated at a dose greater than 5kGy to fill the deep electron and hole traps, and then bleached (OSLDfull). OSLDfull characteristics were investigated in terms of the full bleaching, fading, regeneration of luminescence, dose linearity, and dose sensitivity with various bleaching conditions. For comparison, OSLDs with un-filled deep electron/hole traps (OSLDempty) were investigated in the same manner. RESULTS The fading for OSLDfull exhibited stable signals after 10min, for 1 and 10Gy. The mean supra-linear index values for OSLDfull were 1.001±0.001 for doses from 2 to 10Gy. Small variations in dose sensitivity were obtained for OSLDfull within standard deviations of 0.85% and 0.71%, whereas those of OSLDempty decreased by 2.3% and 4.2% per 10Gy for unfiltered and filtered bleaching devices, respectively. CONCLUSIONS Under the bleaching conditions determined in this study, clinical dosimetry with OSLDfull is highly stable, minimizing the changes in dose sensitivity or linearity for the clinical dose.
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Miri N, Lehmann J, Legge K, Vial P, Greer PB. Virtual EPID standard phantom audit (VESPA) for remote IMRT and VMAT credentialing. Phys Med Biol 2017; 62:4293-4299. [PMID: 28248642 DOI: 10.1088/1361-6560/aa63df] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A virtual EPID standard phantom audit (VESPA) has been implemented for remote auditing in support of facility credentialing for clinical trials using IMRT and VMAT. VESPA is based on published methods and a clinically established IMRT QA procedure, here extended to multi-vendor equipment. Facilities are provided with comprehensive instructions and CT datasets to create treatment plans. They deliver the treatment directly to their EPID without any phantom or couch in the beam. In addition, they deliver a set of simple calibration fields per instructions. Collected EPID images are uploaded electronically. In the analysis, the dose is projected back into a virtual cylindrical phantom. 3D gamma analysis is performed. 2D dose planes and linear dose profiles are provided and can be considered when needed for clarification. In addition, using a virtual flat-phantom, 2D field-by-field or arc-by-arc gamma analyses are performed. Pilot facilities covering a range of planning and delivery systems have performed data acquisition and upload successfully. Advantages of VESPA are (1) fast turnaround mainly driven by the facility's capability of providing the requested EPID images, (2) the possibility for facilities performing the audit in parallel, as there is no need to wait for a phantom, (3) simple and efficient credentialing for international facilities, (4) a large set of data points, and (5) a reduced impact on resources and environment as there is no need to transport heavy phantoms or audit staff. Limitations of the current implementation of VESPA for trials credentialing are that it does not provide absolute dosimetry, therefore a Level I audit is still required, and that it relies on correctly delivered open calibration fields, which are used for system calibration. The implemented EPID based IMRT and VMAT audit system promises to dramatically improve credentialing efficiency for clinical trials and wider applications.
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Affiliation(s)
- Narges Miri
- School of Mathematical and Physical Sciences, The University of Newcastle, Newcastle, Australia
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Kron T, Lehmann J, Greer PB. Dosimetry of ionising radiation in modern radiation oncology. Phys Med Biol 2016; 61:R167-205. [DOI: 10.1088/0031-9155/61/14/r167] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Clark CH, Aird EGA, Bolton S, Miles EA, Nisbet A, Snaith JAD, Thomas RAS, Venables K, Thwaites DI. Radiotherapy dosimetry audit: three decades of improving standards and accuracy in UK clinical practice and trials. Br J Radiol 2015; 88:20150251. [PMID: 26329469 DOI: 10.1259/bjr.20150251] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Dosimetry audit plays an important role in the development and safety of radiotherapy. National and large scale audits are able to set, maintain and improve standards, as well as having the potential to identify issues which may cause harm to patients. They can support implementation of complex techniques and can facilitate awareness and understanding of any issues which may exist by benchmarking centres with similar equipment. This review examines the development of dosimetry audit in the UK over the past 30 years, including the involvement of the UK in international audits. A summary of audit results is given, with an overview of methodologies employed and lessons learnt. Recent and forthcoming more complex audits are considered, with a focus on future needs including the arrival of proton therapy in the UK and other advanced techniques such as four-dimensional radiotherapy delivery and verification, stereotactic radiotherapy and MR linear accelerators. The work of the main quality assurance and auditing bodies is discussed, including how they are working together to streamline audit and to ensure that all radiotherapy centres are involved. Undertaking regular external audit motivates centres to modernize and develop techniques and provides assurance, not only that radiotherapy is planned and delivered accurately but also that the patient dose delivered is as prescribed.
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Affiliation(s)
- Catharine H Clark
- 1 Department of Medical Physics, Royal Surrey County Hospital, Guildford, Surrey, UK.,2 Radiation Dosimetry Group, National Physical Laboratory, Teddington, Middlesex, UK
| | - Edwin G A Aird
- 3 RTTQA Group, Mount Vernon Hospital, Northwood, Middlesex, UK
| | - Steve Bolton
- 4 Medical Physics and Engineering Department, Christie Hospital NHS Foundation Trust, Manchester, UK.,5 Institute of Physics and Engineering in Medicine, York, UK
| | | | - Andrew Nisbet
- 1 Department of Medical Physics, Royal Surrey County Hospital, Guildford, Surrey, UK.,6 Department of Physics, University of Surrey, Guildford, UK
| | - Julia A D Snaith
- 2 Radiation Dosimetry Group, National Physical Laboratory, Teddington, Middlesex, UK
| | - Russell A S Thomas
- 2 Radiation Dosimetry Group, National Physical Laboratory, Teddington, Middlesex, UK
| | - Karen Venables
- 3 RTTQA Group, Mount Vernon Hospital, Northwood, Middlesex, UK
| | - David I Thwaites
- 7 Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW, Australia
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Conheady CF, Gagliardi FM, Ackerly T. Characterising an aluminium oxide dosimetry system. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2015. [PMID: 26224358 DOI: 10.1007/s13246-015-0365-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
In vivo dosimetry is recommended as a defence-in-depth strategy in radiotherapy treatments and is currently employed by clinics around the world. The characteristics of a new optically stimulated luminescence dosimetry system were investigated for the purpose of replacing an aging thermoluminescence dosimetry system for in vivo dosimetry. The stability of the system was not sufficient to satisfy commissioning requirements and therefore it has not been released into clinical service at this time.
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Affiliation(s)
- Clement F Conheady
- William Buckland Radiation Oncology, Alfred Health, Melbourne, Australia.
| | - Frank M Gagliardi
- William Buckland Radiation Oncology, Alfred Health, Melbourne, Australia.,School of Health Sciences, RMIT University, Melbourne, Australia
| | - Trevor Ackerly
- William Buckland Radiation Oncology, Alfred Health, Melbourne, Australia.,School of Health Sciences, RMIT University, Melbourne, Australia
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Lye J, Kenny J, Lehmann J, Dunn L, Kron T, Alves A, Cole A, Williams I. A 2D ion chamber array audit of wedged and asymmetric fields in an inhomogeneous lung phantom. Med Phys 2015; 41:101712. [PMID: 25281951 DOI: 10.1118/1.4896097] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
PURPOSE The Australian Clinical Dosimetry Service (ACDS) has implemented a new method of a nonreference condition Level II type dosimetric audit of radiotherapy services to increase measurement accuracy and patient safety within Australia. The aim of this work is to describe the methodology, tolerances, and outcomes from the new audit. METHODS The ACDS Level II audit measures the dose delivered in 2D planes using an ionization chamber based array positioned at multiple depths. Measurements are made in rectilinear homogeneous and inhomogeneous phantoms composed of slabs of solid water and lung. Computer generated computed tomography data sets of the rectilinear phantoms are supplied to the facility prior to audit for planning of a range of cases including reference fields, asymmetric fields, and wedged fields. The audit assesses 3D planning with 6 MV photons with a static (zero degree) gantry. Scoring is performed using local dose differences between the planned and measured dose within 80% of the field width. The overall audit result is determined by the maximum dose difference over all scoring points, cases, and planes. Pass (Optimal Level) is defined as maximum dose difference ≤3.3%, Pass (Action Level) is ≤5.0%, and Fail (Out of Tolerance) is >5.0%. RESULTS At close of 2013, the ACDS had performed 24 Level II audits. 63% of the audits passed, 33% failed, and the remaining audit was not assessable. Of the 15 audits that passed, 3 were at Pass (Action Level). The high fail rate is largely due to a systemic issue with modeling asymmetric 60° wedges which caused a delivered overdose of 5%-8%. CONCLUSIONS The ACDS has implemented a nonreference condition Level II type audit, based on ion chamber 2D array measurements in an inhomogeneous slab phantom. The powerful diagnostic ability of this audit has allowed the ACDS to rigorously test the treatment planning systems implemented in Australian radiotherapy facilities. Recommendations from audits have led to facilities modifying clinical practice and changing planning protocols.
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Affiliation(s)
- Jessica Lye
- Australian Clinical Dosimetry Service, Yallambie, Victoria 3085, Australia
| | - John Kenny
- Australian Clinical Dosimetry Service, Yallambie, Victoria 3085, Australia and Radiation Oncology Queensland, Toowoomba, Queensland 4350, Australia
| | - Joerg Lehmann
- Australian Clinical Dosimetry Service, Yallambie, Victoria 3085, Australia and School of Applied Science, RMIT University, Melbourne 3000, Australia
| | - Leon Dunn
- Australian Clinical Dosimetry Service, Yallambie, Victoria 3085, Australia
| | - Tomas Kron
- School of Applied Science, RMIT University, Melbourne 3000, Australia and Peter MacCallum Cancer Centre, Melbourne 3008, Australia
| | - Andrew Alves
- Australian Clinical Dosimetry Service, Yallambie, Victoria 3085, Australia
| | - Andrew Cole
- Australian Clinical Dosimetry Service, Yallambie, Victoria 3085, Australia and Australian Radiation Protection and Nuclear Safety Agency, Yallambie, Victoria 3085, Australia
| | - Ivan Williams
- Australian Clinical Dosimetry Service, Yallambie, Victoria 3085, Australia and School of Applied Science, RMIT University, Melbourne 3000, Australia
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Alves ADC, Lye J, Kenny J, Dunn L, Lehmann J, Cole A, Kron T, Butler D, Johnston P, Williams I. Long term OSLD reader stability in the ACDS level one audit. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2014; 38:151-6. [PMID: 25500810 PMCID: PMC4445253 DOI: 10.1007/s13246-014-0320-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 12/04/2014] [Indexed: 11/09/2022]
Abstract
The Australian Clinical Dosimetry Service (ACDS) has demonstrated the capacity to perform a basic dosimetry audit on all radiotherapy clinics across Australia. During the ACDS’s three and a half year trial the majority of the audits were performed using optically stimulated luminescence dosimeters (OSLD) mailed to facilities for exposure to a reference dose, and then returned to the ACDS for analysis. This technical note investigates the stability of the readout process under the large workload of the national dosimetry audit. The OSLD readout uncertainty contributes to the uncertainty of several terms of the dose calculation equation and is a major source of uncertainty in the audit. The standard deviation of four OSLD readouts was initially established at 0.6 %. Measurements over 13 audit batches—each batch containing 200−400 OSLDs—showed variability (0.5−0.9 %) in the readout standard deviation. These shifts have not yet necessitated a change to the audit scoring levels. However, a standard deviation in OSLD readouts greater than 0.9 % will change the audit scoring levels. We identified mechanical wear on the OSLD readout adapter as a cause of variability in readout uncertainty, however, we cannot rule out other causes. Additionally we observed large fluctuations in the distribution of element correction factors (ECF) for OSLD batches. We conclude that the variability in the width of the ECF distribution from one batch to another is not caused by variability in readout uncertainty, but rather by variations in the OSLD stock.
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Affiliation(s)
- Andrew D C Alves
- Australian Clinical Dosimetry Service, Yallambie, VIC, 3085, Australia,
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Seco J, Clasie B, Partridge M. Review on the characteristics of radiation detectors for dosimetry and imaging. Phys Med Biol 2014; 59:R303-47. [PMID: 25229250 DOI: 10.1088/0031-9155/59/20/r303] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The enormous advances in the understanding of human anatomy, physiology and pathology in recent decades have led to ever-improving methods of disease prevention, diagnosis and treatment. Many of these achievements have been enabled, at least in part, by advances in ionizing radiation detectors. Radiology has been transformed by the implementation of multi-slice CT and digital x-ray imaging systems, with silver halide films now largely obsolete for many applications. Nuclear medicine has benefited from more sensitive, faster and higher-resolution detectors delivering ever-higher SPECT and PET image quality. PET/MR systems have been enabled by the development of gamma ray detectors that can operate in high magnetic fields. These huge advances in imaging have enabled equally impressive steps forward in radiotherapy delivery accuracy, with 4DCT, PET and MRI routinely used in treatment planning and online image guidance provided by cone-beam CT. The challenge of ensuring safe, accurate and precise delivery of highly complex radiation fields has also both driven and benefited from advances in radiation detectors. Detector systems have been developed for the measurement of electron, intensity-modulated and modulated arc x-ray, proton and ion beams, and around brachytherapy sources based on a very wide range of technologies. The types of measurement performed are equally wide, encompassing commissioning and quality assurance, reference dosimetry, in vivo dosimetry and personal and environmental monitoring. In this article, we briefly introduce the general physical characteristics and properties that are commonly used to describe the behaviour and performance of both discrete and imaging detectors. The physical principles of operation of calorimeters; ionization and charge detectors; semiconductor, luminescent, scintillating and chemical detectors; and radiochromic and radiographic films are then reviewed and their principle applications discussed. Finally, a general discussion of the application of detectors for x-ray nuclear medicine and ion beam imaging and dosimetry is presented.
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Affiliation(s)
- Joao Seco
- Department of Radiation Oncology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114, USA
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Lehmann J, Dunn L, Lye JE, Kenny JW, Alves ADC, Cole A, Asena A, Kron T, Williams IM. Angular dependence of the response of the nanoDot OSLD system for measurements at depth in clinical megavoltage beams. Med Phys 2014; 41:061712. [DOI: 10.1118/1.4875698] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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