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Beveridge S, Alves A, Hussein M, Clark CH, Jornet N, Viegas CCB, Reniers B, Alvarez PE, Azangwe G, Chelminski K, Dimitriadis A, Kazantsev P, Swamidas J. An international film dosimetry intercomparison to establish a multi-center audit framework. Med Phys 2024. [PMID: 39316455 DOI: 10.1002/mp.17428] [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: 12/20/2023] [Revised: 08/14/2024] [Accepted: 09/06/2024] [Indexed: 09/26/2024] Open
Abstract
BACKGROUND In 2021, a Technical Meeting was hosted by the International Atomic Energy Agency (IAEA) where it was recommended that a standardized method for assessing the accuracy of film dose calculations should be established. PURPOSE To design an audit that evaluates the accuracy of film dosimetry processes. To propose a framework for identifying out-of-tolerance results and to perform an international pilot study to test the audit design. METHODS Six members of an international Dosimetry Audit Network (DAN) developed an audit for radiochromic film dosimetry. A single host center provided the materials to each participating DAN member to conduct the audits. Materials included: (1) a set of two irradiated audit films (10 Sq: 10 cm × 10 cm, 15 Sq: 15 cm × 15 cm), (2) a reference calibration film set, and (3) a blank sheet of film. The participants were blinded to the dose and tasked with producing dose maps using their standard film dosimetry process. Average Region-Of-Interest (ROI: 2 cm × 2 cm) dose was measured from the dose maps and compared to the known dose. In the audit, all participants used their local scanning and software protocols. Film calibration was performed in two distinct ways: (1) using a calibration film set which was provided by the host center and (2) using a calibration film set which was locally irradiated. Several variations of the audit were also performed to examine how scanning and software processing can affect film dosimetry results. In the first variation of the audit (VariantA), a set of film scans was processed using five different software solutions. In the second variation of the audit (VariantB), all films were scanned on the same scanner and processed using two in-house software solutions. RESULTS Taking one film scan from each participant, the standard deviations (1σ) (SD) in the dose returned from the host calibration and returned from the local calibration were ±7.2% and ±6.5% respectively, with variations from -12.4% to 12.9% of the known dose. The larger dose variations in the data set were attributed to the corrections applied for variations in scanner brightness during processing and incorrectly assigned calibration doses. When the raw image data set was processed by an expert user of each software solution (VariantA) the SDs were ±2.7% and ±3.7% for in-house and vendor-based software, respectively. When the films were scanned on a single scanner and processed with the two in-house software solutions (VariantB) the results had a SD of ±2.3%. CONCLUSIONS An audit has been designed and tested for radiotherapy film dosimetry at an international level. A framework for diagnosing issues within a film dosimetry process has been proposed that could be used to audit centers that use film as a dosimeter. Incorporating quality assurance throughout the film process is important in obtaining accurate and consistent film dosimetry. A better understanding of vendor-based software systems is necessary for users to process accurate and consistent film dosimetry.
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Affiliation(s)
- Sabeena Beveridge
- Australian Radiation Protection and Nuclear Safety Agency, Australian Clinical Dosimetry Service, Victoria, Australia
| | - Andrew Alves
- Australian Radiation Protection and Nuclear Safety Agency, Australian Clinical Dosimetry Service, Victoria, Australia
| | | | - Catharine H Clark
- National Physical Laboratory, Middlesex, UK
- Radiotherapy Physics, University College London Hospital, London, UK
- Dept Medical Physics and Bioengineering, University College London, London, UK
| | - Núria Jornet
- Servei de Radiofísica I Radioprotecció, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | | | | | - Paola Elisa Alvarez
- IROC Houston Quality Assurance Center, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Godfrey Azangwe
- Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Seibersdorf, Austria
| | - Krzysztof Chelminski
- Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Seibersdorf, Austria
| | - Alexis Dimitriadis
- Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Seibersdorf, Austria
| | - Pavel Kazantsev
- Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Seibersdorf, Austria
| | - Jamema Swamidas
- Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Seibersdorf, Austria
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Chen Q, Zhao X, Setianegara J, Hao Y, Zhao T, Zhang T, Darafsheh A. Response characterization of radiochromic OC-1 films in photon, electron, and proton beams. Med Phys 2024. [PMID: 39186784 DOI: 10.1002/mp.17356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 07/19/2024] [Accepted: 08/01/2024] [Indexed: 08/28/2024] Open
Abstract
BACKGROUND Radiochromic film (RCF) dosimeters with their high spatial resolution and tissue equivalent properties are conveniently used for two-dimensional and small-field dosimetry. OC-1 is a new model of RCF dosimeter that was commercially introduced recently. Due to its novelty there is a need to characterize its response in various radiation beam types. PURPOSE To study the response of OC-1 RCFs to megavoltage clinical x-ray, electron, and proton beams, as well as kilovoltage x-ray beams used in a small animal research irradiator. MATERIALS AND METHODS OC-1 RCFs were cut into ∼4 × 4 cm2 pieces. RCF samples were irradiated at various dose levels in the range 0.5-120 Gy using different modalities; a small animal radiation research platform (SARRP) (220 kVp), a medical linear accelerator (6 MV, 10 MV, 15 MV, 6 MV FFF, 10 MV FFF photon beams, as well as 6 and 20 MeV electron beams), and a gantry-mounted proton therapy synchrocyclotron. In order to study any dependency on the fractionation scheme, same dose was delivered at several fractions to a set of films. Different dose rates in the range 200-600 MU/min were delivered to a set of films to investigate any dose rate dependency. The films were scanned pre-irradiation and at 48 h post-irradiation using a flatbed scanner. The net optical density (OD) was measured for red, green, and blue color channel for each film. The orientation dependency was studied by scanning the films at eight different orientations. In order to study the temporal evolution of the response of the films, film samples were irradiated at 10 and 50 Gy using 6 MV photon beams and were scanned upon irradiation at certain time intervals up to 3 months. The spectral response of the films were studied over the visible range using a spectrometer. RESULTS For megavoltage photon, electron, and plateau region of the proton beams, we did not observe a significant dependency on the beam quality, dose rate, and fractionation scheme. At the kV beam, an unusual over-response was observed in the films' net OD. An orientation dependency in the response of the films with a sinusoidal trend was observed. The response of the films increased with time following a double or triple exponential trend. The spectral absorption peaks were blue-shifted with dose. CONCLUSION OC-1 RCFs were found to be reliable dosimeters with no significant energy dependency in MV range for photon and electron beams including the FFF beams. They over-respond when irradiated by kV x-ray beams compared to MV x-ray beams. Caution must be exercised to maintain the orientation of the films when scanning. Due to the temporal growth in the net OD of the films, same post-irradiation time interval must be used for scanning the calibration and test films.
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Affiliation(s)
- Qinghao Chen
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Xiandong Zhao
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Jufri Setianegara
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Yao Hao
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Tianyu Zhao
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Tiezhi Zhang
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Arash Darafsheh
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
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Bradley DA, Lam SE, Nawi SNM, Taheri A, Abdul Sani F, Ung NM, Alzimami K, Khandaker MU, Moradi F. Graphite foils as potential skin and epithelium dosimeters at therapeutic photon energies. Appl Radiat Isot 2024; 210:111371. [PMID: 38815447 DOI: 10.1016/j.apradiso.2024.111371] [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: 12/29/2023] [Revised: 04/18/2024] [Accepted: 05/24/2024] [Indexed: 06/01/2024]
Abstract
This work builds upon a prior study, examining the dosimetric utility of pencil lead and thin graphitic sheets, focusing upon the measurement of skin doses within the mammographic regime. In recognizing the near soft-tissue equivalence of graphite and the earlier-observed favourable thermoluminescence yield of thin sheets of graphite, this has led to present study of 50 μm thick graphite for parameters typical of external beam fractionated radiotherapy and skin dose evaluations. The graphite layers were annealed and then stacked to form an assembly of 0.5 mm nominal thickness. Using a 6 MV photon beam and delivering doses from 2- to 60 Gy, irradiations were conducted, the assembly first forming a superficial layer to a solid water phantom and subsequently underlying a 1.5 cm bolus, seeking to circumvent the build-up to electronic equilibrium for skin treatments. Investigations were made of several dosimetric properties arising from the thermoluminescence yield of the 50 μm thick graphite slabs, in particular proportionality and sensitivity to dose. The results show excellent sensitivity within the dose range of interest, the thermoluminescence response varying with increasing depth through the stacked graphite layers, obtaining a coefficient of determination of 90%. Acknowledging there to be considerable challenge in accurately matching skin thickness with dose, the graphite sheets have nevertheless shown considerable promise as dosimeters of skin, sensitive in determination of dose from the surface of the graphite through to sub-dermal depth thicknesses.
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Affiliation(s)
- D A Bradley
- Applied Physics and Radiation Technologies Group, CCDCU, Sunway University, Malaysia; School of Mathematics and Physics, University of Surrey, Guildford, United Kingdom.
| | - S E Lam
- Applied Physics and Radiation Technologies Group, CCDCU, Sunway University, Malaysia
| | - S N Mat Nawi
- Applied Physics and Radiation Technologies Group, CCDCU, Sunway University, Malaysia
| | - A Taheri
- Applied Physics and Radiation Technologies Group, CCDCU, Sunway University, Malaysia
| | - F Abdul Sani
- Department of Physics, University of Malaya, Kuala Lumpur, Malaysia
| | - N M Ung
- Clinical Oncology Unit, Faculty of Medicine, University of Malaya, Malaysia
| | - K Alzimami
- Department of Radiological Sciences, King Saud University, Saudi Arabia
| | - M U Khandaker
- Applied Physics and Radiation Technologies Group, CCDCU, Sunway University, Malaysia
| | - F Moradi
- Multimedia University, Persiaran Multimedia, Cyberjaya, Malaysia
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Malhotra A, Carpentier EE, Duzenli C. Recommendations for using analytical anisotropic algorithm and AcurosXB for epidermal dose calculations in breast radiotherapy from an in vivo Gafchromic film study. J Appl Clin Med Phys 2024; 25:e14416. [PMID: 38812120 PMCID: PMC11302804 DOI: 10.1002/acm2.14416] [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: 02/12/2024] [Revised: 03/27/2024] [Accepted: 04/25/2024] [Indexed: 05/31/2024] Open
Abstract
BACKGROUND AND PURPOSE This study recommends clinical epidermal dose calculation methods based on in-vivo film measurements and registered skin dose distributions with the Eclipse (Varian Medical Systems) treatment planning system's Analytical Anisotropic Algorithm (AAA) and Acuros XB (AXB) dose calculation algorithms. MATERIALS AND METHODS Eighteen AAA V13.6 breast plans were recalculated using AXB (dose to medium) V13.5 with the same beam parameters and monitor units as in the original plans. These are compared against in-vivo Gafchromic film measurements from the lateral and inferior breast regions. Three skin structures in the treatment planning system are evaluated: a surface layer of voxels of the body contour, a 0.2 cm internal skin rind, and a 0.5 cm internal skin rind. RESULTS Systematic shifts are demonstrated between the film measurements of skin dose and the Eclipse dose calculations. On average, the dose to the surface layer of pixels is underestimated by AAA by 8% and overestimated by AXB by 3%. A 5 mm skin rind extended into the body can increase epidermal dose calculations on average by 8% for AAA and 4% for AXB. CONCLUSION This is the first study to register in-vivo skin dose distributions in the breast to the treatment planning system for comparison. Based on the results from this study it is recommended that epidermal dose is calculated with a 0.5 cm skin rind for the AAA algorithm and with rind thickness up to 0.2 cm for the AXB algorithm.
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Affiliation(s)
- Aria Malhotra
- BC CancerVancouverBritish ColumbiaCanada
- Department of Physics and AstronomyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Emilie E. Carpentier
- BC CancerVancouverBritish ColumbiaCanada
- Department of Physics and AstronomyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Cheryl Duzenli
- BC CancerVancouverBritish ColumbiaCanada
- Department of Physics and AstronomyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of SurgeryDivision of Radiation Oncology and Experimental RadiotherapeuticsUniversity of British ColumbiaVancouverBritish ColumbiaCanada
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Raj S, Shree N, Ganesh KM. Effect of glass compression plate on EBT-XD film dosimetry for pretreatment quality assurance of stereotactic body radiotherapy. Rep Pract Oncol Radiother 2024; 29:357-361. [PMID: 39144269 PMCID: PMC11321779 DOI: 10.5603/rpor.101095] [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: 11/21/2023] [Accepted: 05/31/2024] [Indexed: 08/16/2024] Open
Abstract
Background EBT-XD film specially designed for high dose verifications such as stereotactic treatments. The dose response of the film can be affected by several factors, the curly nature of the film being one of them. In this study this curly nature of the film was investigated for stereotactic body radiotherapy (SBRT) plan verifications. Materials and methods For this study, 18 SBRT (11 prostate, 3 spines, and 4 lungs) cases were enrolled. For all the cases, VMAT plans were created in the Monaco treatment planning system and plan was delivered in Elekta Versa HD linear accelerator and delivered fluence was captured by EBT-XD films. All films were scanned with and without a compression plate. All the films were analyzed using the single-channel film method using the red channel. Results A significant difference in the gamma passing rates (GPR) for the films scanned with and without the compression plate was observed. The maximum percentage differences in GPR between using and not using a compression plate were 12.7% for 1% 1 mm, 8.1% for 2% 2 mm, 7.5% for 3% 2 mm, and 5% for 3% 3mm criteria. Similarly, the mean %difference in GPR was 5.8% for 1% 1 mm, 2.4% for 2% 2 mm, 1.6% for 3% 2 mm and 0.96% for 3% 3 mm criteria. Conclusion The results suggest that placing a compression plate over the film during scanning provided a great advantage in achieving a more accurate gamma passing rate irrespective of gamma criteria.
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Affiliation(s)
- Sathiya Raj
- Department of Radiation Physics, Kidwai Memorial Institute of Oncology, Bangalore, India
| | - Nithya Shree
- Department of Radiation Physics, Kidwai Memorial Institute of Oncology, Bangalore, India
| | - K M Ganesh
- Department of Radiation Physics, Kidwai Memorial Institute of Oncology, Bangalore, India
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Bantan H, Yasuda H. Reading of gafchromic EBT-3 film using an overhead scanner. Biomed Phys Eng Express 2024; 10:055004. [PMID: 38941982 DOI: 10.1088/2057-1976/ad5cf8] [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: 02/28/2024] [Accepted: 06/28/2024] [Indexed: 06/30/2024]
Abstract
Gafchromic film, a commercially available radiochromic film, has been developed and widely used as an effective tool for radiation dose verification and quality assurance in radiotherapy. However, the orientation effect in scanning a film remains a concern for practical application in beam profile monitoring. To resolve this issue, the authors introduced a novel method using an overhead scanner (OHS) coupled with a tracing light board instead of a conventional flatbed scanner (FBS) to read Gafchromic EBT3 films. We investigated the orientation effect of the EBT3 film with a regular hexagonal shape after irradiation with 5 Gy x-rays (160 kV, 6.3 mA) and compared the digitized images acquired using a commercially available OHS (CZUR Aura) and a conventional FBS (EPSON GT-X980). As a result, RGB color intensities acquired from the OHS showed significantly lower orientation effect of the color intensities of RGB components than those from FBS. This finding indicates the high potential of the proposed method for achieving more precise two-dimensional dosimetry. Further studies are required to confirm the effectiveness of this method under different irradiation conditions over a wider dose range.
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Affiliation(s)
- H Bantan
- Department of Radiation Biophysics, Research Institute for Radiation Biology and Medicine (RIRBM), Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551, Japan
- Phoenix Leader Education Program (Hiroshima Initiative) for Renaissance from Radiation Disaster, Hiroshima University, Kasumi 1-2-3 Minami-ku, Hiroshima 734-8553, Japan
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3 Minami-ku, Hiroshima, 734-8553, Japan
| | - H Yasuda
- Department of Radiation Biophysics, Research Institute for Radiation Biology and Medicine (RIRBM), Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551, Japan
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7
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Diaz-Martinez VD, Cyr M, Devic S, Tomic N, Lewis DF, Enger SA. Investigation of dosimetric characteristics of radiochromic film in response to alpha particles emitted from Americium-241. Med Phys 2024. [PMID: 38767310 DOI: 10.1002/mp.17133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 02/15/2024] [Accepted: 03/15/2024] [Indexed: 05/22/2024] Open
Abstract
BACKGROUND In radiotherapy, it is essential to deliver prescribed doses to tumors while minimizing damage to surrounding healthy tissue. Accurate measurements of absorbed dose are required for this purpose. Gafchromic® external beam therapy (EBT) radiochromic films have been widely used in radiotherapy. While the dosimetric characteristics of the EBT3 model film have been extensively studied for photon and charged particle beams (protons, electrons, and carbon ions), little research has been done on α $\alpha$ -particle dosimetry. α $\alpha$ -emitting radionuclides have gained popularity in cancer treatment due to their high linear energy transfer, short range in tissue, and ability to spare surrounding organs at risk, thereby delivering a more localized dose distribution to the tumor. Therefore, a dose-calibration film protocol for α $\alpha$ -particles is required. PURPOSE This study aimed to develop a dose-calibration protocol for the α $\alpha$ -particle emitting radionuclide 241Am, using Monte Carlo (MC) simulations and measurements with unlaminated EBT3 films. METHODS In this study, a MC-based user code was developed using the Geant4 simulation toolkit to model and simulate an 241Am source and an unlaminated EBT3 film. Two simulations were performed: one with voxelized geometries of the EBT3 active volume composition and the other using water. The dose rate was calculated within a region of interest in the voxelized geometries. Unlaminated EBT3 film pieces were irradiated with the 241Am source at various exposure times inside a black box. Film irradiations were compared to a 6-MV photon beam from a Varian TrueBeam machine. The simulated dose rate was used to convert the exposure times into absorbed doses to water, describing a radiochromic-film-based reference dosimetry protocol for α $\alpha$ -particles. The irradiated films were scanned and through an in-house Python script, the normalized pixel values from the green-color channel of scanned film images were analyzed. RESULTS The 241Am energy spectra obtained from the simulations were in good agreement with IAEA and NIST databases, having differences < $<$ 0.516% for the emitted γ $\gamma$ -rays and produced characteristic x-rays and < $<$ 0.006% for the α $\alpha$ -particles. Due to the short range of α $\alpha$ -particles, there was no energy deposition in the voxels outside the active 241Am source region projected onto the film surface. Thus, the total dose rate within the voxels covering the source was 0.847 ± $\pm$ 0.003 Gy/min within the sensitive layer of the film (LiPCDA) and 0.847 ± $\pm$ 0.004 Gy/min in water, indicating that the active volume can be considered water equivalent for the 241Am beam quality. A novel approach was employed in α $\alpha$ -film dosimetry using an exponential fit for the green channel, which showed promising results by reducing the uncertainty in dose estimation within 5%. Although the statistical analysis did not reveal significant differences between the 6-MV photon beam and the α $\alpha$ calibration curves, the dose-response curves exhibited the expected behavior. CONCLUSIONS The developed MC user code simulated the experimental setup for α $\alpha$ -dosimetry using radiochromic film with acceptable uncertainty. Unlaminated EBT3 film is suitable for the dosimetry of α $\alpha$ -radiation at low doses and can be used in conjunction with other unlaminated GafChromic® films for quality assurance and research purposes.
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Affiliation(s)
- Victor D Diaz-Martinez
- Medical Physics Unit, Department of Oncology, Faculty of Medicine, McGill University, Montréal, Québec, Canada
| | - Mélodie Cyr
- Medical Physics Unit, Department of Oncology, Faculty of Medicine, McGill University, Montréal, Québec, Canada
| | - Slobodan Devic
- Medical Physics Unit, Department of Oncology, Faculty of Medicine, McGill University, Montréal, Québec, Canada
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada
| | - Nada Tomic
- Medical Physics Unit, Department of Oncology, Faculty of Medicine, McGill University, Montréal, Québec, Canada
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada
| | | | - Shirin A Enger
- Medical Physics Unit, Department of Oncology, Faculty of Medicine, McGill University, Montréal, Québec, Canada
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada
- Research Institute of McGill University Health Centre, Montréal, Québec, Canada
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Rodrigues-Machado FC, Janitz E, Bernard S, Bekerat H, McEwen M, Renaud J, Enger SA, Childress L, Sankey JC. Radiation hardness of open Fabry-Pérot microcavities. OPTICS EXPRESS 2024; 32:17189-17196. [PMID: 38858908 DOI: 10.1364/oe.522332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 04/07/2024] [Indexed: 06/12/2024]
Abstract
High-finesse microcavities offer a platform for compact, high-precision sensing by employing high-reflectivity, low-loss mirrors to create effective optical path lengths that are orders of magnitude larger than the device geometry. Here, we investigate the radiation hardness of Fabry-Pérot microcavities formed from dielectric mirrors deposited on the tips of optical fibers. The microcavities are irradiated under both conventional (∼ 0.1 Gy/s) and ultrahigh (FLASH, ∼ 20 Gy/s) radiotherapy dose rates. Within our measurement sensitivity of ∼ 40 ppm loss, we observe no degradation in the mirror absorption after irradiation with over 300 Gy accumulated dose. This result highlights the excellent radiation hardness of the dielectric mirrors forming the cavities, enabling new optics-based, real-time, in-vivo, tissue-equivalent radiation dosimeters with ∼ 10 micron spatial resolution (our motivation), as well as other applications in high-radiation environments.
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Kozicki M, Sąsiadek-Andrzejczak E, Wach R, Maras P. Flexible Cotton Fabric-Based Ionizing Radiation Dosimeter for 2D Dose Distribution Measurements over a Wide Dose Range at High Dose Rates. Int J Mol Sci 2024; 25:2916. [PMID: 38474163 DOI: 10.3390/ijms25052916] [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: 02/08/2024] [Revised: 02/23/2024] [Accepted: 02/26/2024] [Indexed: 03/14/2024] Open
Abstract
This work presents an ecological, flexible 2D radiochromic dosimeter for measuring ionizing radiation in the kilogray dose range. Cotton woven fabric made of cellulose was volume-modified with nitrotetrazolium blue chloride as a radiation-sensitive compound. Its features include a color change during exposure from yellowish to purple-brown and flexibility that allows it to adapt to various shapes. It was found that (i) the dose response is up to ~80 kGy, (ii) it is independent of the dose rate for 1.1-73.1 kGy/min, (iii) it can be measured in 2D using a flatbed scanner, (iv) the acquired images can be filtered using a mean filter, which improves its dose resolution, (v) the dose resolution is -0.07 to -0.4 kGy for ~0.6 to ~75.7 kGy for filtered images, and (vi) two linear dose subranges can be distinguished: ~0.6 to ~7.6 kGy and ~9.9 to ~62.0 kGy. The dosimeter combined with flatbed scanner reading and data processing using dedicated software packages constitutes a comprehensive system for measuring dose distributions for objects with complex shapes.
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Affiliation(s)
- Marek Kozicki
- Department of Mechanical Engineering, Informatics and Chemistry of Polymer Materials, Faculty of Materials Technologies and Textile Design, Lodz University of Technology, Żeromskiego 116, 90-543 Lodz, Poland
| | - Elżbieta Sąsiadek-Andrzejczak
- Department of Mechanical Engineering, Informatics and Chemistry of Polymer Materials, Faculty of Materials Technologies and Textile Design, Lodz University of Technology, Żeromskiego 116, 90-543 Lodz, Poland
| | - Radosław Wach
- Institute of Applied Radiation Chemistry, Faculty of Chemistry, Lodz University of Technology, Wroblewskiego 15, 93-590 Lodz, Poland
| | - Piotr Maras
- Department of Radiotherapy Planning, Copernicus Hospital, Pabianicka 62, 93-513 Lodz, Poland
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Palmer AL, Nash D. Radiochromic film dosimetry in radiotherapy: a survey of current practice in the United Kingdom. Br J Radiol 2024; 97:646-651. [PMID: 38273671 PMCID: PMC11027307 DOI: 10.1093/bjr/tqae008] [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: 10/05/2023] [Revised: 11/03/2023] [Accepted: 11/06/2023] [Indexed: 01/27/2024] Open
Abstract
OBJECTIVES To establish the variation in film dosimetry usage in radiotherapy centres across the United Kingdom. To identify consensus and highlight areas of potential improvement to enhance radiotherapy dosimetry verification with film. METHODS A survey questionnaire was designed by members of the Institute of Physics and Engineering in Medicine Interdepartmental Dosimetry Audit Group via Microsoft Forms and distributed to all Heads of Radiotherapy Physics in the United Kingdom. The survey was open from June 19, 2023, to July 31, 2023. RESULTS Forty responses were received from the 62 radiotherapy centres in the United Kingdom, of which 58% were currently using film dosimetry and a further 7 were keen to commence use. Many reported film use had decreased in recent years but was still valuable particularly for commissioning and implementing new techniques. The variation and consensus of methods for film dosimetry calibration, measurement, and application was established. A review of barriers to implementation and methods to reduce uncertainty were included in the assessment. CONCLUSIONS A comprehensive assessment of film dosimetry usage in radiotherapy in the United Kingdom has been collated, which demonstrates a wide variation in methods, across typical clinical users, but maintains film as a valuable dosimetry option. ADVANCES IN KNOWLEDGE This research provides a snapshot of current film dosimetry use across the United Kingdom. It examines the variation and consensus of practice to which individual users can compare their systems, and identifies opportunities to improvement in the accuracy of film dosimetry.
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Affiliation(s)
- Antony L Palmer
- Medical Physics, Portsmouth Hospitals University NHS Trust, Portsmouth, PO6 3LY, United Kingdom
| | - David Nash
- Medical Physics, Portsmouth Hospitals University NHS Trust, Portsmouth, PO6 3LY, United Kingdom
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Yasuda H, Morioka S. Comparative study on measurements of radiochromic films using portable colorimeters. Sci Rep 2024; 14:3384. [PMID: 38336983 PMCID: PMC10858274 DOI: 10.1038/s41598-024-54017-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 02/07/2024] [Indexed: 02/12/2024] Open
Abstract
The recently proposed method for on-site radiation dosimetry by a combination of radiochromic film and portable colorimeter was tested for six combinations of two popular Gafchromic films (EBT3 and EBT-XD) and three commercially available portable colorimeters (nix pro2, nix spectro2 and Spectro1 Pro; abbreviated to "NixP", "NixS" and "SpoP", respectively). EBT3 and EBT-XD were irradiated with X-rays (160 kV, 6.3 mA) up to 40 Gy and 80 Gy, respectively, and the radiation-induced color levels of RGB and CMYK components were measured with the three colorimeters. Angle dependence was examined by reading at 15° intervals. As a result, it was judged that all combinations would work effectively under certain irradiation conditions. NixP and NixS were applicable to a wider dose range for both films, while SpoP fit a lower dose range. On the other hand, SpoP showed an advantageous feature of no angular dependence in reading films, while NixP and NixS showed significant angle-dependent changes. These differences are considered to be attributable to the different geometries of LED light emission, which came from all directions (360°) in SpoP, 4 directions in NixP, and 8 directions in NixS. These findings are expected to expand the applicability of the novel method to various occasions of on-site dosimetry.
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Affiliation(s)
- Hiroshi Yasuda
- Research Institute for Radiation Biology and Medicine (RIRBM), Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, 734-8553, Japan.
| | - Shido Morioka
- School of Medicine, Hiroshima University, Kasumi 1-2-3 Minami-ku, Hiroshima, 734-8553, Japan
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Yalvac B, Reulens N, Reniers B. Early results of a remote dosimetry audit program for lung stereotactic body radiation therapy. Phys Imaging Radiat Oncol 2024; 29:100544. [PMID: 38327761 PMCID: PMC10848021 DOI: 10.1016/j.phro.2024.100544] [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: 05/31/2023] [Revised: 01/25/2024] [Accepted: 01/26/2024] [Indexed: 02/09/2024] Open
Abstract
Background and purpose A dosimetry audit program based on alanine electron paramagnetic resonance (EPR) and radiochromic film dosimetry, may be a valuable tool for monitoring and improving the quality of lung stereotactic body radiotherapy (SBRT). The aim of this study was to report the initial, independent assessment of the dosimetric accuracy for lung SBRT practice using these dosimeters in combination with a novel phantom design. Materials and Methods The audit service was a remote audit program performed on a commercial lung phantom preloaded with film and alanine detectors. An alanine pellet was placed in the centre of the target simulated using silicone in a 3D-printed mould. Large film detectors were placed coronally through the target and the lung/tissue interface and analysed using gamma analysis. The beam output was always checked on the same day with alanine dosimetry in water. We audited 29 plans from 14 centres up to now. Results For the alanine results 28/29 plans were within 5 % with 19/29 plans being within 3 %. The passing rates were > 95 % for the film through the target for 27/29 plans and 17/29 plans for the film at the lung/tissue interface. For three plans the passing rate was < 90 % for the film on top of the lungs. Conclusions The preliminary results were very satisfactory for both detectors. The high passing rates for the film in the interface region indicate good performance of the treatment planning systems. The phantom design was robust and performed well on several treatment systems.
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Affiliation(s)
- Burak Yalvac
- Universiteit Hasselt, CMK, NuTeC, Diepenbeek, Belgium
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13
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Cederhag J, Kadesjö N, Nilsson M, Alstergren P, Shi XQ, Hellén-Halme K. Comparison of absorbed doses and organ doses measured with thermoluminescent dosimeters and Gafchromic film for cone beam computed tomography examination of the posterior mandibular region in a head phantom. Oral Surg Oral Med Oral Pathol Oral Radiol 2023; 136:769-776. [PMID: 37625926 DOI: 10.1016/j.oooo.2023.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 06/26/2023] [Accepted: 07/02/2023] [Indexed: 08/27/2023]
Abstract
OBJECTIVES We aimed to map the correlation between thermoluminescent dosimeters (TLDs) and Gafchromic film for measuring absorbed doses and to compare minimum, maximum, and mean absorbed doses over larger regions of interest and at various craniofacial organs and tissues during cone beam computed tomography (CBCT) exposure of the mandibular third molar region. STUDY DESIGN We positioned TLDs at 75 measurement points in a head phantom. Gafchromic film was cut to the same shape as the 5 levels of the phantom and was placed on top of the TLDs. Both dosimetry methods thus included the surface of each level simultaneously. CBCT scans were made using a 5 × 5 cm field of view and a rotation angle of 200°. Measurements included absorbed dose distributions, doses at all 75 points, and minimum, maximum, and mean doses within organs and tissues. RESULTS The correlation of point-dose measurements at all TLD sites with doses measured on film was strong (R2 = 0.9687), with greatest correlation at lower doses (<2 mGy). Large deviations between TLD and film measurements of minimum and maximum doses and absorbed doses to the organs occurred at all 5 levels. TLD positioning failed to cover several organ sites; for these, only absorbed dose measurements from the film were available. CONCLUSIONS TLDs were unable to sample dose distributions and gradients accurately. The characteristics of Gafchromic LD-V1 film make it a favorable alternative in dental CBCT dosimetry.
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Affiliation(s)
- Josefine Cederhag
- Department of Oral and Maxillofacial Radiology, Faculty of Odontology, Malmö University, Malmö, Sweden.
| | - Nils Kadesjö
- Medical Radiation Physics, Karolinska University Hospital, Stockholm, Sweden
| | - Mats Nilsson
- Department of Medical Radiation Physics, Lund University, Malmö, Sweden
| | - Per Alstergren
- Department of Orofacial Pain and Jaw Function, Faculty of Odontology, Malmö University, Malmö, Sweden; Specialized Pain Rehabilitation, Skåne University Hospital, Lund, Sweden; Scandinavian Center for orofacial Neurosciences, Malmö University, Malmö, Sweden
| | - Xie-Qi Shi
- Department of Oral and Maxillofacial Radiology, Faculty of Odontology, Malmö University, Malmö, Sweden; Section of Oral and Maxillofacial Radiology, Department of Clinical Dentistry, University of Bergen, Bergen, Norway
| | - Kristina Hellén-Halme
- Department of Oral and Maxillofacial Radiology, Faculty of Odontology, Malmö University, Malmö, Sweden
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Liu K, Jorge PG, Tailor R, Moeckli R, Schüler E. Comprehensive evaluation and new recommendations in the use of Gafchromic EBT3 film. Med Phys 2023; 50:7252-7262. [PMID: 37403570 PMCID: PMC10766858 DOI: 10.1002/mp.16593] [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: 09/14/2022] [Revised: 06/06/2023] [Accepted: 06/11/2023] [Indexed: 07/06/2023] Open
Abstract
BACKGROUND Gafchromic film's unique properties of tissue-equivalence, dose-rate independence, and high spatial resolution make it an attractive choice for many dosimetric applications. However, complicated calibration processes and film handling limits its routine use. PURPOSE We evaluated the performance of Gafchromic EBT3 film after irradiation under a variety of measurement conditions to identify aspects of film handling and analysis for simplified but robust film dosimetry. METHODS The short- (from 5 min to 100 h) and long-term (months) film response was evaluated for clinically relevant doses of up to 50 Gy for accuracy in dose determination and relative dose distributions. The dependence of film response on film-read delay, film batch, scanner type, and beam energy was determined. RESULTS Scanning the film within a 4-h window and using a standard 24-h calibration curve introduced a maximum error of 2% over a dose range of 1-40 Gy, with lower doses showing higher uncertainty in dose determination. Relative dose measurements demonstrated <1 mm difference in electron beam parameters such as depth of 50% of the maximum dose value (R50 ), independent of when the film was scanned after irradiation or the type of calibration curve used (batch-specific or time-specific calibration curve) if the same default scanner was used. Analysis of films exposed over a 5-year period showed that using the red channel led to the lowest variation in the measured net optical density values for different film batches, with doses >10 Gy having the lowest coefficient of variation (<1.7%). Using scanners of similar design produced netOD values within 3% after exposure to doses of 1-40 Gy. CONCLUSIONS This is the first comprehensive evaluation of the temporal and batch dependence of Gafchromic EBT3 film evaluated on consolidated data over 8 years. The relative dosimetric measurements were insensitive to the type of calibration applied (batch- or time-specific) and in-depth time-dependent dosimetric signal behaviors can be established for film scanned outside of the recommended 16-24 h post-irradiation window. We generated guidelines based on our findings to simplify film handling and analysis and provide tabulated dose- and time-dependent correction factors to achieve this without reducing the accuracy of dose determination.
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Affiliation(s)
- Kevin Liu
- Division of Radiation Oncology, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Graduate School of Biomedical Sciences, The University of Texas, Houston, Texas, USA
| | - Patrik Gonçalves Jorge
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Ramesh Tailor
- Division of Radiation Oncology, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Graduate School of Biomedical Sciences, The University of Texas, Houston, Texas, USA
| | - Raphaël Moeckli
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Emil Schüler
- Division of Radiation Oncology, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Graduate School of Biomedical Sciences, The University of Texas, Houston, Texas, USA
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15
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Mégrourèche J, Bekerat H, Bian J, Bui A, Sankey J, Childress L, Enger SA. Development of a hydrated electron dosimeter for radiotherapy applications: A proof of concept. Med Phys 2023; 50:7245-7251. [PMID: 37334736 DOI: 10.1002/mp.16555] [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: 01/04/2023] [Revised: 05/04/2023] [Accepted: 05/11/2023] [Indexed: 06/20/2023] Open
Abstract
BACKGROUND Hydrated electrons, which are short-lived products of radiolysis in water, increase the optical absorption of water, providing a pathway toward near-tissue-equivalent clinical radiation dosimeters. This has been demonstrated in high-dose-per-pulse radiochemistry research, but, owing to the weak absorption signal, its application in existing low-dose-per-pulse radiotherapy provided by clinical linear accelerators (linacs) has yet to be investigated. PURPOSE The aims of this study were to measure the optical absorption associated with hydrated electrons produced by clinical linacs and to assess the suitability of the technique for radiotherapy (⩽ 1 cGy per pulse) applications. METHODS 40 mW of 660-nm laser light was sent five passes through deionized water contained in a 10× 4 × $\times 4\times$ 2 cm3 glass-walled cavity by using four broadband dielectric mirrors, two on each side of the cavity. The light was collected with a biased silicon photodetector. The water cavity was then irradiated by a Varian TrueBeam linac with both photon (10 MV FFF, 6 MV FFF, 6 MV) and electron beams (6 MeV) while monitoring the transmitted laser power for absorption transients. Radiochromic EBT3 film measurements were also performed for comparison. RESULTS Examination of the absorbance profiles showed clear absorption changes in the water when radiation pulses were delivered. Both the amplitude and the decay time of the signal appeared consistent with the absorbed dose and the characteristics of the hydrated electrons. By using literature value for the hydrated electron radiation chemical yield (3.0±0.3), we inferred doses of 2.1±0.2 mGy (10 MV FFF), 1.3±0.1 mGy (6 MV FFF), 0.45±0.06 mGy (6 MV) for photons, and 0.47±0.05 mGy (6 MeV) for electrons, which differed from EBT3 film measurements by 0.6%, 0.8%, 10%, and 15.7%, respectively. The half-life of the hydrated electrons in the solution was ∼ 24 μ $\umu$ s. CONCLUSIONS By measuring 660-nm laser light transmitted through a cm-scale, multi-pass water cavity, we observed absorption transients consistent with hydrated electrons generated by clinical linac radiation. The agreement between our inferred dose and EBT3 film measurements suggests this proof-of-concept system represents a viable pathway toward tissue-equivalent dosimeters for clinical radiotherapy applications.
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Affiliation(s)
- Julien Mégrourèche
- Medical Physics Unit, Department of Oncology, McGill University, Montréal, Québec, Canada
| | - Hamed Bekerat
- Medical Physics Unit, Department of Oncology, McGill University, Montréal, Québec, Canada
- Radiation Oncology Department, Jewish General Hospital, Montréal, Québec, Canada
| | - Jingyi Bian
- Medical Physics Unit, Department of Oncology, McGill University, Montréal, Québec, Canada
| | - Alaina Bui
- Medical Physics Unit, Department of Oncology, McGill University, Montréal, Québec, Canada
| | - Jack Sankey
- Department of Physics, McGill University, Montréal, Québec, Canada
| | - Lilian Childress
- Department of Physics, McGill University, Montréal, Québec, Canada
| | - Shirin A Enger
- Medical Physics Unit, Department of Oncology, McGill University, Montréal, Québec, Canada
- Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada
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16
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Mena S, Karkour N, Alaphilippe V, Botero JP, Jiménez M, Linget D, Gibelin L, Le Ven V, Marquet A, Mellouh S, Josson E, Benassou W, Muñoz-Berbel X, Guirado G, Guardiola C. New opto-electro-mechanical sensor for two-dimensions dosimetry based on radiochromic films. Sci Rep 2023; 13:16787. [PMID: 37798315 PMCID: PMC10556105 DOI: 10.1038/s41598-023-43387-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 09/22/2023] [Indexed: 10/07/2023] Open
Abstract
This work presents the validation of a new Opto‒Electro-Mechanical (MOEM) system consisting of a matrix of photodetectors for two-dimensional dosimetry evaluation with radiochromic films. The proposed system is based on a 5 × 10 matrix of photodetectors controlled by both in-house electronic circuit and graphical user interface, which enables optical measurements directly. We present the first tests performed in an X-ray machine and 137Cs source with that array by using Gafchromic EBT3 films. We obtained similar results than with a standard method (e.g. flat-bed scanner). Results were compared with Monte Carlo simulations and very good agreement was found. Results show the feasibility of using this system for dose evaluations. To the best of our knowledge, this is the first MOEM sensor for radiotherapy. Further developments are ongoing to create an advanced 16 × 16 LDRs system covering 1.6 cm × 1.6 cm with a 1 mm of spatial resolution. We point to develop a portable dosimetry tool delivering dose maps in real time to improve the clinical application of radiochromic films.
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Affiliation(s)
- S Mena
- Departament de Química, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain.
- Instituto de Microelectrónica de Barcelona, (IMB-CNM, CSIC), 08193, Bellaterra, Spain.
| | - N Karkour
- Université Paris‒Saclay, CNRS/IN2P3, IJCLab, 91405, Orsay, France
| | - V Alaphilippe
- Université Paris‒Saclay, CNRS/IN2P3, IJCLab, 91405, Orsay, France
| | - J P Botero
- Universidad de los Andes, Carrera 1 No. 18ª-10, Bogotá, Colombia
| | - M Jiménez
- Instituto de Microelectrónica de Barcelona, (IMB-CNM, CSIC), 08193, Bellaterra, Spain
| | - D Linget
- Université Paris‒Saclay, CNRS/IN2P3, IJCLab, 91405, Orsay, France
| | - L Gibelin
- Université Paris‒Saclay, CNRS/IN2P3, IJCLab, 91405, Orsay, France
| | - V Le Ven
- Université Paris‒Saclay, CNRS/IN2P3, IJCLab, 91405, Orsay, France
| | - A Marquet
- ESME (École Supérieure Mécanique et Electronique) Sudria, Paris, France
| | - S Mellouh
- ESME (École Supérieure Mécanique et Electronique) Sudria, Paris, France
| | - E Josson
- ESME (École Supérieure Mécanique et Electronique) Sudria, Paris, France
| | - W Benassou
- Faculté de Chimie, Université Paris-Saclay, Orsay, France
| | - X Muñoz-Berbel
- Instituto de Microelectrónica de Barcelona, (IMB-CNM, CSIC), 08193, Bellaterra, Spain
- CIBER de Bioingeniería, Biomateriales y Nanomedicina, Instituto de Salud Carlos III, Madrid, Spain
| | - G Guirado
- Departament de Química, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - C Guardiola
- Instituto de Microelectrónica de Barcelona, (IMB-CNM, CSIC), 08193, Bellaterra, Spain.
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Palmer AL, Nash D, Polak W, Wilby S. Evaluation of a new radiochromic film dosimeter, Gafchomic EBT4, for VMAT, SABR and HDR treatment delivery verification. Phys Med Biol 2023; 68:175003. [PMID: 37499683 DOI: 10.1088/1361-6560/aceb48] [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: 02/03/2023] [Accepted: 07/27/2023] [Indexed: 07/29/2023]
Abstract
Objective.To evaluate a new film for radiotherapy dosimetry, Gafchromic EBT4, compared to the current EBT3. To evaluate dose-response and verify test cases in MV external beam and HDR brachytherapy.Approach. Three lots (batches) of EBT4 and three lots of EBT3 films were calibrated at 6 MV over 0-1200 cGy range, using FilmQAPro software. Signal-to-noise of pixel value, reported dose (RD), and factors affecting dosimetry accuracy were evaluated (rotation of the film at scanning, energy response and post-exposure darkening). Both films were exposed to clinical treatment plans (VMAT prostate, SABR lung, single HDR source dwell, and 'pseudo' 3-channel HDR cervix brachytherapy). Film-RD was compared to TPS-calculated dose.Main results.EBT4 calibration curves had characteristics more favourable than EBT3 for radiation dosimetry, with improved signal to noise in film-RD of EBT4 compared to EBT3 (increase of average 46% in red and green channels at 500 cGy). Film rotation at scanning and post-exposure darkening was similar for the two films. The energy response of EBT4 is similar to EBT3. For all clinical case studies, EBT4 provided better agreement with the TPS-planned doses than EBT3. VMAT prostate gamma 3%/3 mm passing rate, EBT4 100.0% compared to EBT3 97.9%; SABR lung gamma 2%/2 mm, EBT4 99.6% and EBT3 97.9%; HDR cervix gamma 3%/2 mm, EBT4 97.7% and EBT3 95.0%.Significance.These results show EBT4 is superior to EBT3 for radiotherapy dosimetry validation of TPS plan delivery. Fundamental improvements in noise profile and calibration curve are reported for EBT4. All clinical test cases showed EBT4 provided equivalent or smaller difference in measured dose to TPS calculated dose than EBT3. Baseline data is presented on the achievable accuracy of film dosimetry in radiotherapy using the new Gafchromic EBT4 film.
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Affiliation(s)
- Antony L Palmer
- Medical Physics Dept, Portsmouth Hospitals University NHS Trust, Cosham, PO6 3LY, United Kingdom
| | - David Nash
- Medical Physics Dept, Portsmouth Hospitals University NHS Trust, Cosham, PO6 3LY, United Kingdom
| | - Wojciech Polak
- Medical Physics Dept, Portsmouth Hospitals University NHS Trust, Cosham, PO6 3LY, United Kingdom
| | - Sarah Wilby
- Medical Physics Dept, Portsmouth Hospitals University NHS Trust, Cosham, PO6 3LY, United Kingdom
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18
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Arjmand M, Ghassemi F, Rafiepour P, Zeinali R, Riazi-Esfahani H, Beiki-Ardakani A. Dosimetric Investigation of Six Ru-106 Eye Plaques by EBT3 Radiochromic Films and Monte Carlo Simulation. J Biomed Phys Eng 2023; 13:309-316. [PMID: 37609514 PMCID: PMC10440413 DOI: 10.31661/jbpe.v0i0.2010-1206] [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: 10/11/2020] [Accepted: 02/10/2021] [Indexed: 08/24/2023]
Abstract
Background Ophthalmic brachytherapy using radioactive plaques is an effective technique for the treatment of uveal melanoma. Ru-106 eye plaques are considered as interesting issue due to their steep gradient dose. The pre-planning evaluation of dosimetric parameters is essential for the treatment planning system. Objective The current study aims at providing dose distributions of six Ru-106 eye plaques (CCA, CCB, CGD, CIB, COB and COD) using radiochromic EBT3 film, Geant4 Monte Carlo toolkit and the treatment planning software (Plaque Simulator). Material and Methods In this experimental study, an in-house phantom was employed for depth dose measurements with EBT3 films. Also, Geant4.10.5 scoring mesh was implemented to obtain the 2D dose distribution of the plaques. The results were compared with Plaque Simulator software and the manufacturer's (BEBIG) data. The gamma index criterion (3%/3 mm) was used to evaluate dose distributions obtained by the film measurements and Geant4 simulation. Results A good agreement was achieved between simulation and experimental results. Gamma index passing rate was 94.2%, 89.3%, 88.2%, 82.2%, 92.2% and 90.1% for CCA, CCB, CGD, CIB, COB and COD plaques, respectively. Absolute dose rate (mGy/min) obtained by EBT3 film at the depth of 2 mm was 79.4 mGy/min, 81.0 mGy/min, 78.6 mGy/min, 62.2 mGy/min, 75.2 mGy/min and 81.2 mGy/min for CCA, CCB, CGD, CIB, COB and COD plaques, respectively. Conclusion The measured dose distributions and lateral dose profiles may be utilized in the treatment planning system to cover clinical volumes such as the clinical target volume and the gross tumor volume.
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Affiliation(s)
- Mojtaba Arjmand
- Ocular Oncology service, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Fariba Ghassemi
- Retina & Vitreous Service- Ocular Oncology Service, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Payman Rafiepour
- Department of Nuclear Engineering, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Reyhaneh Zeinali
- Department of Medical Physics, Tabriz University of Medical Science, Tabriz, Iran
| | - Hamid Riazi-Esfahani
- Ocular Oncology service, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
- Retina Service, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Akbar Beiki-Ardakani
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
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19
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Pace M, Bonanno E, Borzì GR, Cavalli N, D'Anna A, Gueli AM, Stella G, Zirone L, Marino C. Organ dose in CT: Comparison between measurements and computational methods. Phys Med 2023; 112:102627. [PMID: 37348452 DOI: 10.1016/j.ejmp.2023.102627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/12/2023] [Accepted: 06/13/2023] [Indexed: 06/24/2023] Open
Abstract
PURPOSE This study aims to compare two methods for the organ dose evaluation in computed tomography (CT) in the head- and thorax regions: an experimental method, using radiochromic films, and a computational one, using a commercial software. METHODS Gafchromic® XR-QA2 and EBT-3 were characterized in terms of energetic, angular, and irradiation configurations dependence. Two free-in-air irradiation calibration configurations were employed using a CT scanner: with the sensitive surface of the film orthogonal (OC) and parallel (PC) to the beam axis. Different dose-response curves were obtained by varying the irradiation configurations and the beam quality (BQ). Subsequently, films were irradiated within an anthropomorphic phantom using CT-thorax and -head protocols, and the organ dose values obtained were compared with those provided by the commercial software. RESULTS At different configurations, an unchanged dose response was achieved with EBT-3, while a dose response of 15% was obtained with XR-QA2. By varying BQ, XR-QA2 showed a different response below 10%, while EBT-3 showed a variation below 5% for dose values >20 mGy. For films irradiation angle equal to 90°, the normalized to 0° relative response was 41% for the XR-QA2 model and 83% for the EBT-3 one. Organ dose values obtained with EBT-3 for both configurations and with XR-QA2 for OC were in agreement with the DW values, showing percentage discrepancies of less than 25%. CONCLUSIONS The obtained results showed the potential of EBT-3 in CT patient dosimetry since the lower angular dependence, compared to XR-QA2, compensates for low sensitivity in the diagnostic dose range.
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Affiliation(s)
- Martina Pace
- Medical Physics Department, Humanitas Istituto Clinico Catanese, Misterbianco, CT, Italy
| | - Elisa Bonanno
- Medical Physics Department, Humanitas Istituto Clinico Catanese, Misterbianco, CT, Italy
| | - Giuseppina Rita Borzì
- Medical Physics Department, Humanitas Istituto Clinico Catanese, Misterbianco, CT, Italy
| | - Nina Cavalli
- Medical Physics Department, Humanitas Istituto Clinico Catanese, Misterbianco, CT, Italy
| | - Alessia D'Anna
- Department of Physics and Astronomy E. Majorana, University of Catania, Catania, Italy
| | - Anna Maria Gueli
- Department of Physics and Astronomy E. Majorana, University of Catania, Catania, Italy
| | - Giuseppe Stella
- Department of Physics and Astronomy E. Majorana, University of Catania, Catania, Italy.
| | - Lucia Zirone
- Medical Physics Department, Humanitas Istituto Clinico Catanese, Misterbianco, CT, Italy; Department of Physics and Astronomy E. Majorana, University of Catania, Catania, Italy
| | - Camelo Marino
- Medical Physics Department, Humanitas Istituto Clinico Catanese, Misterbianco, CT, Italy
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Lozares-Cordero S, Bermejo-Barbanoj C, Badías-Herbera A, Ibáñez-Carreras R, Ligorred-Padilla L, Ponce-Ortega JM, González-Pérez V, Gandía-Martínez A, Font-Gómez JA, Blas-Borroy O, González-Ibáñez D. An open-source development based on photogrammetry for a real-time IORT treatment planning system. Phys Med 2023; 112:102622. [PMID: 37331081 DOI: 10.1016/j.ejmp.2023.102622] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 06/02/2023] [Accepted: 06/06/2023] [Indexed: 06/20/2023] Open
Abstract
PURPOSE This study presents a treatment planning system for intraoperative low-energy photon radiotherapy based on photogrammetry from real images of the surgical site taken in the operating room. MATERIAL AND METHODS The study population comprised 15 patients with soft-tissue sarcoma. The system obtains the images of the area to be irradiated with a smartphone or tablet, so that the absorbed doses in the tissue can be calculated from the reconstruction without the need for computed tomography. The system was commissioned using 3D printing of the reconstructions of the tumor beds. The absorbed doses at various points were verified using radiochromic films that were suitably calibrated for the corresponding energy and beam quality. RESULTS The average reconstruction time of the 3D model from the video sequence in the 15 patients was 229,6±7,0 s. The entire procedure, including video capture, reconstruction, planning, and dose calculation was 520,6±39,9 s. Absorbed doses were measured on the 3D printed model with radiochromic film, the differences between these measurements and those calculated by the treatment planning system were 1.4% at the applicator surface, 2.6% at 1 cm, 3.9% at 2 cm and 6.2% at 3 cm. CONCLUSIONS The study shows a photogrammetry-based low-energy photon IORT planning system, capable of obtaining real-time images inside the operating room, immediately after removal of the tumor and immediately before irradiation. The system was commissioned with radiochromic films measurements in 3D-printed model.
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Affiliation(s)
- Sergio Lozares-Cordero
- Physics and Radiation Protection Department, Miguel Servet University Hospital, Zaragoza, Spain.
| | | | - Alberto Badías-Herbera
- Higher Technical School of Industrial Engineering, Polytechnic University of Madrid, Spain
| | | | - Luis Ligorred-Padilla
- Esophagogastric Surgery and Sarcoma Unit (Department of General and Gastrointestinal Surgery), Miguel Servet University Hospital, Zaragoza, Spain
| | | | | | | | - José Antonio Font-Gómez
- Physics and Radiation Protection Department, Miguel Servet University Hospital, Zaragoza, Spain
| | - Olga Blas-Borroy
- Engineering and Maintenance Service, Miguel Servet University Hospital, Zaragoza, Spain
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21
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Pecić S, Vićić M, Belča I, Stojadinović S, Nidžović B, Kurij L, Dević S. Physical wedge as a tool for radiochromic film calibration. Z Med Phys 2023:S0939-3889(23)00077-6. [PMID: 37393128 DOI: 10.1016/j.zemedi.2023.05.008] [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: 03/28/2023] [Revised: 05/17/2023] [Accepted: 05/31/2023] [Indexed: 07/03/2023]
Abstract
Reliable calibration is one of the major challenges in using radiochromic films (RCF) for radiation dosimetry. In this study the feasibility of using dose gradients produced by a physical wedge (PW) for RCF calibration was investigated. The aim was to establish an efficient and reproducible method for calibrating RCF using a PW. Film strips were used to capture the wedge dose profile for five different exposures and the acquired scans were processed to generate corresponding net optical density wedge profiles. The proposed method was compared to the benchmark calibration, following the guidelines for precise calibration using uniform dose fields. The results of the benchmark comparison presented in this paper showed that using a single film strip for measuring wedge dose profile is sufficient for estimating a reliable calibration curve within the recorded dose range. Furthermore, the PW calibration can be extrapolated or extended by using multiple gradients for the optimal coverage of the desired calibration dose range. The method outlined in this paper can be readily replicated using the equipment and expertise commonly found in a radiotherapy center. Once the dose profile and central axis attenuation coefficient of the PW are determined, they can serve as a reference for a variety of calibrations using different types and batches of film. This investigation demonstrated that the calibration curves obtained with the presented PW calibration method are within the bounds of the measurement uncertainty evaluated for the conventional uniform dose field calibration method.
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Affiliation(s)
- Stevan Pecić
- Faculty of Physics, University of Belgrade, Studentski trg 12-16, Belgrade 11000, Serbia.
| | - Miloš Vićić
- Faculty of Physics, University of Belgrade, Studentski trg 12-16, Belgrade 11000, Serbia
| | - Ivan Belča
- Faculty of Physics, University of Belgrade, Studentski trg 12-16, Belgrade 11000, Serbia
| | - Strahinja Stojadinović
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas 75390, TX, United States
| | - Borko Nidžović
- Institute of Oncology and Radiology of Serbia, Pasterova 14, Belgrade 11000, Serbia
| | - Ljubomir Kurij
- University Clinical Center of Serbia, Center for Neurooncology, Gamma Knife, Koste Todorovića 4, Belgrade 11000, Serbia
| | - Slobodan Dević
- Medical Physics Unit, McGill University, Montreal H4A 3J1, QC, Canada; Department of Radiation Oncology, SMBD Jewish General Hospital, Montreal H3T 1E2, QC, Canada
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22
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Nakajima E, Sato H. Characterization of a new radiochromic film (LD-V1) using mammographic beam qualities. Z Med Phys 2023:S0939-3889(23)00072-7. [PMID: 37365089 DOI: 10.1016/j.zemedi.2023.05.004] [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: 01/22/2023] [Revised: 05/16/2023] [Accepted: 05/16/2023] [Indexed: 06/28/2023]
Abstract
PURPOSE Radiochromic film (RCF) is a detector that can obtain a two-dimensional dose distribution with high resolution; it is widely used in medical and industrial fields. Several types of RCFs exist based on their application. The type of RCF mainly used for mammography dose assessment has been discontinued; however, a new type of RCF (LD-V1) has been distributed as a successor. Since the medical use of LD-V1 has rarely been studied, we investigated the response characteristics of LD-V1 in mammography. METHODS Measurements were performed using Mo/Mo and Rh/Ag on a Senographe Pristina mammography device (GE, Fairfield, CT, USA). The reference air kerma was measured using a parallel-plate ionization chamber (PPIC) (C-MA, Applied Engineering Inc, Tokyo, Japan). Pieces of LD-V1 film model were irradiated at the same position where the reference air kerma in air was measured by the PPIC. Irradiation was performed using the time scale method based on the load on the equipment. Two methods of irradiation were considered: placing the detector in air and on the phantom. The LD-V1 was scanned five times at 72 dpi in RGB (48 bit) mode using a flatbed scanner (ES-G11000, Seiko Epson Corp, Nagano, Japan) 24 h following irradiation. The response ratio of the reference air kerma and the air kerma obtained from the LD-V1 were compared and examined for each beam quality and air kerma range. RESULTS AND DISCUSSION When the beam quality was altered, the response ratio varied from 0.8 to 1.2 with respect to the measurement value of the PPIC; however, some outliers were observed. Response ratios were highly variable in the low-dose range; however, as the air kerma increased, the ratios approached 1. Thus, LD-V1 does not need calibration for each beam quality used in mammography. LD-V1 enables air kerma evaluation by creating air kerma response curves under certain X-ray conditions used in mammography. CONCLUSION We suggest that the dose range be limited to 12 mGy or more to keep the response variation with beam qualities below ±20%. If further measurement is required for reducing the response variation, the dose range should be shifted to a higher dose range.
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Affiliation(s)
- Erika Nakajima
- Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Ibaraki Prefecture, Japan.
| | - Hitoshi Sato
- Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Ibaraki Prefecture, Japan
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23
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Sheykholeslami N, Parwaie W, Vaezzadeh V, Babaie M, Farzin M, Geraily G, Karimi AH. Dual application of Polyvinyl Alcohol Glutaraldehyde Methylthymol Blue Fricke hydrogel in clinical practice: Surface dosimeter and bolus. Appl Radiat Isot 2023; 197:110827. [PMID: 37086713 DOI: 10.1016/j.apradiso.2023.110827] [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: 11/08/2022] [Revised: 03/26/2023] [Accepted: 04/17/2023] [Indexed: 04/24/2023]
Abstract
An essential issue is an accurate evaluation of surface dose distribution for such sensitive treatments. This work aimed to feasibility of the dual application of the Ferrous Polyvinyl Alcohol Glutaraldehyde Methylthymol Blue (PVA-GTA-MTB) gel as a bolus compensator and surface dosimeter in breast radiotherapy. The differences between the surface dose measured using PVA-GTA-MTB gel and film dosimetry in the medial and lateral parts of the breast were 3.74% and 4.18%, respectively. A qualitative comparison of the isodose curves showed that the PVA-GTA-MTB bolus creates a uniform dose distribution similar to the superflab bolus in the target volume.
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Affiliation(s)
- Nooshin Sheykholeslami
- Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Wrya Parwaie
- Department of Laboratory Sciences, School of Allied Medical Sciences, Ilam University of Medical Sciences, Iran
| | - Vahid Vaezzadeh
- Radiation Oncology Research Center, Cancer Institute, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Babaie
- Radiation Oncology Research Center, Cancer Institute, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
| | - Mostafa Farzin
- Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Science, Tehran, Iran
| | - Ghazale Geraily
- Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Radiation Oncology Research Center, Cancer Institute, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran.
| | - Amir Hossein Karimi
- Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Radiation Oncology Research Center, Cancer Institute, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran.
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Breglio G, Bernini R, Berruti GM, Bruno FA, Buontempo S, Campopiano S, Catalano E, Consales M, Coscetta A, Cutolo A, Cutolo MA, Di Palma P, Esposito F, Fienga F, Giordano M, Iele A, Iadicicco A, Irace A, Janneh M, Laudati A, Leone M, Maresca L, Marrazzo VR, Minardo A, Pisco M, Quero G, Riccio M, Srivastava A, Vaiano P, Zeni L, Cusano A. Innovative Photonic Sensors for Safety and Security, Part III: Environment, Agriculture and Soil Monitoring. SENSORS (BASEL, SWITZERLAND) 2023; 23:3187. [PMID: 36991894 PMCID: PMC10053851 DOI: 10.3390/s23063187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/05/2023] [Accepted: 03/10/2023] [Indexed: 06/19/2023]
Abstract
In order to complete this set of three companion papers, in this last, we focus our attention on environmental monitoring by taking advantage of photonic technologies. After reporting on some configurations useful for high precision agriculture, we explore the problems connected with soil water content measurement and landslide early warning. Then, we concentrate on a new generation of seismic sensors useful in both terrestrial and under water contests. Finally, we discuss a number of optical fiber sensors for use in radiation environments.
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Affiliation(s)
- Giovanni Breglio
- Dipartimento di Ingegneria Elettrica e delle Tecnologie dell’Informazione, Università degli Studi di Napoli Federico II, Via Claudio 21, 80125 Napoli, Italy
- European Organization for Nuclear Research (CERN), 1211 Geneva, Switzerland
| | - Romeo Bernini
- Istituto per il Rilevamento Elettromagnetico dell’Ambiente, Consiglio Nazionale delle Ricerche, Via Diocleziano 328, 81024 Napoli, Italy
| | - Gaia Maria Berruti
- Gruppo di Optoelettronica e Fotonica, Dipartimento di Ingegneria, Università degli Studi del Sannio, Corso Garibaldi 107, 82100 Benevento, Italy
| | - Francesco Antonio Bruno
- Gruppo di Optoelettronica e Fotonica, Dipartimento di Ingegneria, Università degli Studi del Sannio, Corso Garibaldi 107, 82100 Benevento, Italy
| | - Salvatore Buontempo
- European Organization for Nuclear Research (CERN), 1211 Geneva, Switzerland
- National Institute for Nuclear Physics (INFN), 80125 Napoli, Italy
| | - Stefania Campopiano
- Dipartimento di Ingegneria, Università Degli Studi di Napoli Parthenope, Centro Direzionale Isola C4, 80143 Napoli, Italy
| | - Ester Catalano
- Dipartimento di Ingegneria, Università della Campania Luigi Vanvitelli, Via Roma 29, 81031 Aversa, Italy
- Optosensing Ltd., Via Carlo de Marco 69, 80137 Napoli, Italy
| | - Marco Consales
- Gruppo di Optoelettronica e Fotonica, Dipartimento di Ingegneria, Università degli Studi del Sannio, Corso Garibaldi 107, 82100 Benevento, Italy
| | - Agnese Coscetta
- Dipartimento di Ingegneria, Università della Campania Luigi Vanvitelli, Via Roma 29, 81031 Aversa, Italy
| | - Antonello Cutolo
- Dipartimento di Ingegneria Elettrica e delle Tecnologie dell’Informazione, Università degli Studi di Napoli Federico II, Via Claudio 21, 80125 Napoli, Italy
| | - Maria Alessandra Cutolo
- Dipartimento di Ingegneria Elettrica e delle Tecnologie dell’Informazione, Università degli Studi di Napoli Federico II, Via Claudio 21, 80125 Napoli, Italy
| | - Pasquale Di Palma
- Dipartimento di Ingegneria, Università Degli Studi di Napoli Parthenope, Centro Direzionale Isola C4, 80143 Napoli, Italy
| | - Flavio Esposito
- Dipartimento di Ingegneria, Università Degli Studi di Napoli Parthenope, Centro Direzionale Isola C4, 80143 Napoli, Italy
| | - Francesco Fienga
- Dipartimento di Ingegneria Elettrica e delle Tecnologie dell’Informazione, Università degli Studi di Napoli Federico II, Via Claudio 21, 80125 Napoli, Italy
- European Organization for Nuclear Research (CERN), 1211 Geneva, Switzerland
| | - Michele Giordano
- Istituto per i Polimeri, Compositi e Biomateriali Consiglio Nazionale delle Ricerche, Via Enrico Fermi 1, 80055 Portici, Italy
| | - Antonio Iele
- CERICT SCARL, CNOS Center, Viale Traiano, Palazzo ex Poste, 82100 Benevento, Italy
| | - Agostino Iadicicco
- Dipartimento di Ingegneria, Università Degli Studi di Napoli Parthenope, Centro Direzionale Isola C4, 80143 Napoli, Italy
| | - Andrea Irace
- Dipartimento di Ingegneria Elettrica e delle Tecnologie dell’Informazione, Università degli Studi di Napoli Federico II, Via Claudio 21, 80125 Napoli, Italy
| | - Mohammed Janneh
- CERICT SCARL, CNOS Center, Viale Traiano, Palazzo ex Poste, 82100 Benevento, Italy
| | | | - Marco Leone
- Gruppo di Optoelettronica e Fotonica, Dipartimento di Ingegneria, Università degli Studi del Sannio, Corso Garibaldi 107, 82100 Benevento, Italy
| | - Luca Maresca
- Dipartimento di Ingegneria Elettrica e delle Tecnologie dell’Informazione, Università degli Studi di Napoli Federico II, Via Claudio 21, 80125 Napoli, Italy
| | - Vincenzo Romano Marrazzo
- Dipartimento di Ingegneria Elettrica e delle Tecnologie dell’Informazione, Università degli Studi di Napoli Federico II, Via Claudio 21, 80125 Napoli, Italy
- European Organization for Nuclear Research (CERN), 1211 Geneva, Switzerland
| | - Aldo Minardo
- Dipartimento di Ingegneria, Università della Campania Luigi Vanvitelli, Via Roma 29, 81031 Aversa, Italy
| | - Marco Pisco
- Gruppo di Optoelettronica e Fotonica, Dipartimento di Ingegneria, Università degli Studi del Sannio, Corso Garibaldi 107, 82100 Benevento, Italy
| | - Giuseppe Quero
- Gruppo di Optoelettronica e Fotonica, Dipartimento di Ingegneria, Università degli Studi del Sannio, Corso Garibaldi 107, 82100 Benevento, Italy
| | - Michele Riccio
- Dipartimento di Ingegneria Elettrica e delle Tecnologie dell’Informazione, Università degli Studi di Napoli Federico II, Via Claudio 21, 80125 Napoli, Italy
| | - Anubhav Srivastava
- Dipartimento di Ingegneria, Università Degli Studi di Napoli Parthenope, Centro Direzionale Isola C4, 80143 Napoli, Italy
| | - Patrizio Vaiano
- Gruppo di Optoelettronica e Fotonica, Dipartimento di Ingegneria, Università degli Studi del Sannio, Corso Garibaldi 107, 82100 Benevento, Italy
| | - Luigi Zeni
- Dipartimento di Ingegneria, Università della Campania Luigi Vanvitelli, Via Roma 29, 81031 Aversa, Italy
- Optosensing Ltd., Via Carlo de Marco 69, 80137 Napoli, Italy
| | - Andrea Cusano
- Gruppo di Optoelettronica e Fotonica, Dipartimento di Ingegneria, Università degli Studi del Sannio, Corso Garibaldi 107, 82100 Benevento, Italy
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Zheng Z, Lu H, Hou H, Bai Y, Qiu J, Guo X, Wang JQ, Lin J. Stepwise Crystallization of Millimeter Scale Thorium Cluster Single Crystals as a Bifunctional Platform for X-ray Detection and Shielding. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2206782. [PMID: 36534835 DOI: 10.1002/smll.202206782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 12/06/2022] [Indexed: 06/17/2023]
Abstract
Monitoring and shielding of X-ray radiation are of paramount importance across diverse fields. However, they are frequently realized in separate protocols and a single material integrating both functions remained elusive. Herein, a hexanuclear cluster [Th6 (µ3 -OH)4 (µ3 -O)4 (H2 O)6 ](pba)6 (HCOO)6 (Th-pba-0D) incorporating high-Z thorium cations and 3-(pyridin-4-yl)benzoate ligands that can function as a brand-new dual-module platform for visible detection and efficient shielding of ionizing radiation is demonstrated. Th-pba-0D exhibits rather unique reversible radiochromism upon alternating X-ray and UV irradiation. Moreover, the millimeter scale crystal size of Th-pba-0D renders the penetration depth of X-ray visible to naked eye and leads to the unearthing of its high X-ray attenuation efficiency. Indeed, the shielding efficacy of Th-pba-0D is comparable to that of lead glass containing 40% PbO, and a Th-pba-0D pellet with a thickness of merely 1.2 mm can shield 99.73% X-ray (16 keV). These studies portend the possible utilization of thorium-bearing materials as a bifunctional platform for radiation detection and shielding.
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Affiliation(s)
- Zhaofa Zheng
- School of Nuclear Science and Technology, Xi'an Jiaotong University, No.28, West Xianning Road, Xi'an, 710049, P. R. China
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 2019 Jia Luo Road, Shanghai, 201800, P. R. China
- University of Chinese Academy of Sciences, No.19(A) Yuquan Road, Shijingshan District, Beijing, 100049, P. R. China
| | - Huangjie Lu
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 2019 Jia Luo Road, Shanghai, 201800, P. R. China
- University of Chinese Academy of Sciences, No.19(A) Yuquan Road, Shijingshan District, Beijing, 100049, P. R. China
| | - Huiliang Hou
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 2019 Jia Luo Road, Shanghai, 201800, P. R. China
- University of Chinese Academy of Sciences, No.19(A) Yuquan Road, Shijingshan District, Beijing, 100049, P. R. China
| | - Yaoyao Bai
- School of Nuclear Science and Technology, Xi'an Jiaotong University, No.28, West Xianning Road, Xi'an, 710049, P. R. China
| | - Jie Qiu
- School of Nuclear Science and Technology, Xi'an Jiaotong University, No.28, West Xianning Road, Xi'an, 710049, P. R. China
| | - Xiaofeng Guo
- Department of Chemistry and Alexandra Navrotsky Institute for Experimental Thermodynamics, Washington State University, Fulmer 630, Pullman, WA, 99164-4630, USA
| | - Jian-Qiang Wang
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 2019 Jia Luo Road, Shanghai, 201800, P. R. China
- University of Chinese Academy of Sciences, No.19(A) Yuquan Road, Shijingshan District, Beijing, 100049, P. R. China
| | - Jian Lin
- School of Nuclear Science and Technology, Xi'an Jiaotong University, No.28, West Xianning Road, Xi'an, 710049, P. R. China
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Trivedi G, Singh PP, Oinam AS. Comparison of single catheter versus dual catheter-based EBT3 film calibration for the Ir-192 beam energy. Biomed Phys Eng Express 2023; 9. [PMID: 36796085 DOI: 10.1088/2057-1976/acbc80] [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: 09/16/2022] [Accepted: 02/16/2023] [Indexed: 02/18/2023]
Abstract
Purpose. Films and TLDs have been the common choices for passivein-vivodose measurement in radiotherapy. In the brachytherapy applications, it is very difficult to report and verify the dose at multiple localized high dose gradient regions and also the dose to organ at risk. This study was carried out to introduce a new and accurate calibration method for GafChromic EBT3 films irradiated using Ir-192 photon energy from miniature High Dose Rate (HDR) Brachytherapy source.Materials and methods. Film holder made of Styrofoam was used to hold the EBT3 film at its center. It was placed inside the mini water phantom and the films were irradiated by Ir-192 source of microSelectron HDR afterloading brachytherapy system. Two different setups: Single catheter-based film exposure and dual catheter-based film exposure were compared. The films scanned on a flatbed scanner were analysed in three different color channels: red, green, and blue using Image J software. The dose calibration graphs were generated using the third-order polynomial equations fitted on the data points from two different methods of calibration procedure. Maximum and mean dose difference between TPS calculated and measured was analyzed.Results. The measured dose difference from the TPS calculated doses were evaluated for the three groups of dose ranges (low, medium and high). In the high dose range, standard uncertainty of dose difference are ±2.3%, ±2.9%, and ±2.4% respectively for the red, green, and blue color channel when the TPS calculated dose was compared with single catheter based film calibration equation. Whereas it is observed as 1.3%, 1.4% and 3.1% for the red, green, and blue color channels respectively when compared with the dual catheter based film calibration equation. A test film was exposed to a TPS calculated dose of 666 cGy to validate the calibration equations, single catheter based film calibration equation estimated the dose difference as -9.2%, -7.8% and -3.6% respectively in the red, green, and blue color channels whereas the same were observed as 0.1%, 0.2% and 6.1% respectively when dual catheter based film calibration equation was applied.Conclusion.Source miniature size, reproducible positioning of the film and catheter system inside water medium are the major challenges in the film calibration with Ir-192 beam. To overcome these situations dual catheter-based film calibration was found more accurate and reproducible as compare to the single catheter based film calibration.
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Affiliation(s)
- Gaurav Trivedi
- Post Graduate Institute of Medical Education and Research, India.,Indian Institute of Technology, Ropar, India
| | | | - Arun S Oinam
- Post Graduate Institute of Medical Education and Research, India
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27
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Arous D, Lie JL, Håland BV, Børsting M, Edin NFJ, Malinen E. 2D mapping of radiation dose and clonogenic survival for accurate assessment of in vitroX-ray GRID irradiation effects. Phys Med Biol 2023; 68. [PMID: 36580679 DOI: 10.1088/1361-6560/acaf20] [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: 04/13/2022] [Accepted: 12/29/2022] [Indexed: 12/30/2022]
Abstract
Spatially fractionated radiation therapy (SFRT or GRID) is an approach to deliver high local radiation doses in an 'on-off' pattern. To better appraise the radiobiological effects from GRID, a framework to link local radiation dose to clonogenic survival needs to be developed. A549 lung cancer cells were irradiated in T25 cm2flasks using 220 kV x-rays with an open field or through a tungsten GRID collimator with periodical 5 mm openings and 10 mm blockings. Delivered nominal doses were 2, 5, and 10 Gy. A novel approach for image segmentation was used to locate the centroid of surviving colonies in scanned images of the cell flasks. GafchromicTMfilm dosimetry (GFD) and FLUKA Monte Carlo (MC) simulations were employed to map the dose at each surviving colony centroid. Fitting the linear-quadratic (LQ) function to clonogenic survival data for open field irradiation, the expected survival level at a given dose level was calculated. The expected survival levels were then mapped together with the observed levels in the GRID-irradiated flasks. GFD and FLUKA MC gave similar dose distributions, with a mean peak-to-valley dose ratio of about 5. LQ-parameters for open field irradiation gaveα=0.24±0.02Gy-1andβ=0.019±0.002Gy-2. The mean relative percentage deviation between observed and predicted survival in the (peak; valley) dose regions was (4.6; 3.1) %, (26.6; -1.0) %, and (129.8; -2.3) % for 2, 5 and 10 Gy, respectively. In conclusion, a framework for mapping of surviving colonies following GRID irradiation together with predicted survival levels from homogeneous irradiation was presented. For the given cell line, our findings indicate that GRID irradiation causes reduced survival in the peak regions compared to an open field configuration.
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Affiliation(s)
- Delmon Arous
- Department of Physics, University of Oslo, PO Box 1048 Blindern, N-0316, Oslo, Norway.,Department of Medical Physics, The Norwegian Radium Hospital, Oslo University Hospital, PO Box 4953 Nydalen, N-0424 Oslo, Norway
| | - Jacob Larsen Lie
- Department of Physics, University of Oslo, PO Box 1048 Blindern, N-0316, Oslo, Norway
| | - Bjørg Vårli Håland
- Department of Physics, University of Oslo, PO Box 1048 Blindern, N-0316, Oslo, Norway
| | - Magnus Børsting
- Department of Physics, University of Oslo, PO Box 1048 Blindern, N-0316, Oslo, Norway
| | | | - Eirik Malinen
- Department of Physics, University of Oslo, PO Box 1048 Blindern, N-0316, Oslo, Norway.,Department of Medical Physics, The Norwegian Radium Hospital, Oslo University Hospital, PO Box 4953 Nydalen, N-0424 Oslo, Norway
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28
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Dong X, Tian Y, Wang F, Chen C, Wang Y, Ma J. Gold-Nanoparticle-Enhanced Radio-Fluorogenic Hydrogel Sensor for Low Radiation Doses in Clinical Radiotherapy. Polymers (Basel) 2022; 14:4841. [PMID: 36432968 PMCID: PMC9694710 DOI: 10.3390/polym14224841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 11/08/2022] [Indexed: 11/12/2022] Open
Abstract
Radio-fluorogenic hydrogel dosimeters are urgently needed in radiotherapy for 3D dose verification. However, few hydrogel sensors have been reported at low absorbed doses under 2 Gy which meets the requirements of clinical practice. Here, we report a new type of gold-nanoparticle-enhanced radio-fluorogenic agarose hydrogel with coumarin as the dose-responsive material. An optimal composition of 3 wt% of agarose, 0.1 mM of gold nanoparticles, and 0.5 mM coumarin was selected. The addition of gold nanoparticles enhanced the hydroxyl radicals generated from the radiolysis of water, which can react with coumarin and generate fluorescent 7-hydroxy-coumarin and, eventually, achieve low-dose verification of 0-2.4 Gy with a high linear correlation coefficient. These findings provide an effective method for 3D dose verification, and will inspire the development of other radio-fluorogenic sensing hydrogels as well.
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Affiliation(s)
| | | | | | | | - Yunlong Wang
- College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China
| | - Jun Ma
- College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China
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Vuori S, Colinet P, Lehtiö JP, Lemiere A, Norrbo I, Granström M, Konu J, Ågren G, Laukkanen P, Petit L, Airaksinen AJ, van Goethem L, Le Bahers T, Lastusaari M. Reusable radiochromic hackmanite with gamma exposure memory. MATERIALS HORIZONS 2022; 9:2773-2784. [PMID: 36069965 DOI: 10.1039/d2mh00593j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Radiochromic films are used as position-sensitive dose meters in e.g. medical physics and radiation processing. The currently available films like those based on lithium-10,12-pentacosdiynoate or leucomalachite green are either toxic or non-reusable, or both. There is thus a great need for a sustainable solution for radiochromic detection. In the present work, we present a suitable candidate: hackmanite with the general formula Na8Al6Si6O24(Cl,S)2. This material is known as a natural intelligent material capable of changing color when exposed to ultraviolet radiation or X-rays. Here, we show for the first time that hackmanites are also radiochromic when exposed to alpha particles, beta particles (positrons) or gamma radiation. Combining experimental and computational data we elucidate the mechanism of gamma-induced radiochromism in hackmanites. We show that hackmanites can be used for gamma dose mapping in high dose applications as well as a memory material that has the one-of-a-kind ability to remember earlier gamma exposure. In addition to satisfying the requirements of sustainability, hackmanites are non-toxic and the films made of hackmanite are reusable thus showing great potential to replace the currently available radiochromic films.
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Affiliation(s)
- Sami Vuori
- Department of Chemistry, University of Turku, FI-20014 Turku, Finland.
- University of Turku Graduate School (UTUGS), Doctoral Programme in Physical and Chemical Sciences (PCS), FI-20014 Turku, Finland
| | - Pauline Colinet
- Laboratoire de Chimie, University of Lyon, ENS de Lyon, CNRS, Université Lyon 1, UMR 5182, Lyon, France.
| | - Juha-Pekka Lehtiö
- University of Turku Graduate School (UTUGS), Doctoral Programme in Physical and Chemical Sciences (PCS), FI-20014 Turku, Finland
- Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland
| | - Arnaud Lemiere
- Photonics Laboratory, Tampere University, FI-33720 Tampere, Finland
| | - Isabella Norrbo
- Department of Chemistry, University of Turku, FI-20014 Turku, Finland.
| | | | - Jari Konu
- Department of Chemistry, University of Jyväskylä, FI-40014 Jyväskylä, Finland
| | - Göran Ågren
- FOI, Swedish Defence Research Agency, SE-90182 Umeå, Sweden
| | - Pekka Laukkanen
- Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland
| | - Laeticia Petit
- Photonics Laboratory, Tampere University, FI-33720 Tampere, Finland
| | - Anu J Airaksinen
- Department of Chemistry, Turku PET Centre, University of Turku, FI-20521 Turku, Finland
| | - Ludo van Goethem
- Mineralogical Society of Antwerp, Boterlaarbaan 225, 2100 Deurne, Belgium
| | - Tangui Le Bahers
- Laboratoire de Chimie, University of Lyon, ENS de Lyon, CNRS, Université Lyon 1, UMR 5182, Lyon, France.
| | - Mika Lastusaari
- Department of Chemistry, University of Turku, FI-20014 Turku, Finland.
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30
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Andrew Katsifis G, McKenzie DR, Hill R, Connor MO, Milross C, Suchowerska N. Radiation dose perturbation at the tissue interface with PEEK and Titanium bone implants: Monte Carlo simulation, treatment planning and film dosimetry. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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31
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Peripheral and surface dose assessment using diode and Gafchromic EBT3 films dosimeters for different radiotherapy techniques. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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32
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Quantitative comparison of different dosimetry methods in orthovoltage X-ray therapy. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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33
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van Eeden D, Joubert MM, du Plessis FCP. Evaluation of artificial neural network designs for Gafchromic™ film calibration with Tc-99m and digital photos. Appl Radiat Isot 2022; 187:110311. [PMID: 35753171 DOI: 10.1016/j.apradiso.2022.110311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 05/31/2022] [Accepted: 06/02/2022] [Indexed: 11/16/2022]
Affiliation(s)
- Déte van Eeden
- Department of Medical Physics, Faculty of Health Sciences, University of the Free State, Bloemfontein, South Africa.
| | - Maria M Joubert
- Department of Medical Physics, Faculty of Health Sciences, University of the Free State, Bloemfontein, South Africa
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34
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Liu X, Van Slyke AL, Pearson E, Shoniyozov K, Redler G, Wiersma RD. Improving the efficiency of small animal 3D-printed compensator IMRT with beamlet intensity total variation regularization. Med Phys 2022; 49:5400-5408. [PMID: 35608256 DOI: 10.1002/mp.15764] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 02/23/2022] [Accepted: 05/11/2022] [Indexed: 12/30/2022] Open
Abstract
PURPOSE There is growing interest in the use of modern 3D printing technology to implement intensity-modulated radiation therapy (IMRT) on the preclinical scale that is analogous to clinical IMRT. However, current 3D-printed IMRT methods suffer from complex modulation patterns leading to long delivery times, excess filament usage, and less accurate compensator fabrication. In this work, we have developed a total variation regularization (TVR) approach to address these issues. METHODS TVR-IMRT was used to optimize the beamlet intensity map, which was then converted to a thickness of the corresponding compensator attenuation region in copper-doped polylactic acid (PLA) filament. IMRT and TVR-IMRT heart and lung plans were generated for two different mice using three, five, or seven gantry angles. The total compensator thickness, total variation of compensator beamlet thicknesses, total variation of beamlet intensities, and exposure time were compared. The individual field doses and composite dose were delivered to film for one plan and gamma analysis was performed. RESULTS In total, 12 mice heart and lung plans were generated for both IMRT and TVR-IMRT cases. Across all cases, it was found that TVR-IMRT reduced the total variation of compensator beamlet thicknesses and beamlet intensities by 54 ± 4 % $54\pm 4\%$ and 50 ± 3 % $50\pm 3\%$ on average when compared to standard 3D-printed compensator IMRT. On average, the total mass of compensator material consumed and radiation beam-on time were reduced by 45 ± 6 % $45\pm 6\%$ and 24 ± 4 % $24\pm 4\%$ , respectively, whereas dose metrics remained comparable. Heart plan compensators were printed and delivered to film and subsequent gamma analysis performed for each of the single fields as well as the composite dose. For the composite delivery, a passing rate of 89.1% for IMRT and 95.4% for TVR-IMRT was achieved for a 3 % / 0.3 $3\%/0.3$ mm criterion. CONCLUSIONS TVR can be applied to small animal IMRT beamlet intensities to produce fluence maps and subsequent 3D-printed compensator patterns with significantly less complexity while still maintaining similar dose conformity to traditional IMRT. This can simplify/accelerate the 3D printing process, reduce the amount of filament required, and reduce overall beam-on time to deliver a plan.
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Affiliation(s)
- Xinmin Liu
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Alexander L Van Slyke
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Erik Pearson
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, Illinois, USA
| | - Khayrullo Shoniyozov
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Gage Redler
- Moffitt Cancer Center, Department of Radiation Oncology, Tampa, Florida, USA
| | - Rodney D Wiersma
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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35
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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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36
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K S, E JJS. Studies on the tissue and water equivalence of some 3D printing materials and dosimeters. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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37
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Ji W, Kim JB, Kim JJ. Measurement of low energy beta radiation from Ni-63 by using peeled-off Gafchromic EBT3 film. NUCLEAR ENGINEERING AND TECHNOLOGY 2022. [DOI: 10.1016/j.net.2022.05.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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38
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Modified Geometry of 106Ru Asymmetric Eye Plaques to Improve Dosimetric Calculations in Ophthalmic Brachytherapy. J Pers Med 2022; 12:jpm12050723. [PMID: 35629144 PMCID: PMC9144752 DOI: 10.3390/jpm12050723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 04/22/2022] [Accepted: 04/27/2022] [Indexed: 11/29/2022] Open
Abstract
Ru/Rh asymmetric plaques for ophthalmic brachytherapy have special geometric designs with a cutout intended to prevent irradiation of critical ocular structures proximal to the tumor. In this work, we present new geometric models for PENELOPE+PenEasy Monte Carlo simulations of these applicators, differing from the vendor-reported geometry, that better match their real geometry to assess their dosimetric impact. Simulation results were benchmarked to experimental dosimetric data from radiochromic film measurements, data provided by the manufacturer in the calibration certificates, and other experimental results published in the literature, obtaining, in all cases, better agreement with the modified geometries. The clinical impact of the new geometric models was evaluated by simulating real clinical cases using patient-specific eye models. The cases calculated using the modified geometries presented higher doses to the critical structures proximal to the cutout region. The modified geometric models presented in this work provide a more accurate representation of the asymmetric plaques, greatly improving the agreement between Monte Carlo calculations and experimental measurements. Lack of consideration of accurate geometric models has been shown to be translated into notable increases in dose to organs at risk in clinical cases.
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39
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Biglin ER, Aitkenhead AH, Price GJ, Chadwick AL, Santina E, Williams KJ, Kirkby KJ. A preclinical radiotherapy dosimetry audit using a realistic 3D printed murine phantom. Sci Rep 2022; 12:6826. [PMID: 35474242 PMCID: PMC9042835 DOI: 10.1038/s41598-022-10895-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 04/05/2022] [Indexed: 11/08/2022] Open
Abstract
Preclinical radiation research lacks standardized dosimetry procedures that provide traceability to a primary standard. Consequently, ensuring accuracy and reproducibility between studies is challenging. Using 3D printed murine phantoms we undertook a dosimetry audit of Xstrahl Small Animal Radiation Research Platforms (SARRPs) installed at 7 UK centres. The geometrically realistic phantom accommodated alanine pellets and Gafchromic EBT3 film for simultaneous measurement of the dose delivered and the dose distribution within a 2D plane, respectively. Two irradiation scenarios were developed: (1) a 10 × 10 mm2 static field targeting the pelvis, and (2) a 5 × 5 mm2 90° arc targeting the brain. For static fields, the absolute difference between the planned dose and alanine measurement across all centres was 4.1 ± 4.3% (mean ± standard deviation), with an overall range of - 2.3 to 10.5%. For arc fields, the difference was - 1.2% ± 6.1%, with a range of - 13.1 to 7.7%. EBT3 dose measurements were greater than alanine by 2.0 ± 2.5% and 3.5 ± 6.0% (mean ± standard deviation) for the static and arc fields, respectively. 2D dose distributions showed discrepancies to the planned dose at the field edges. The audit demonstrates that further work on preclinical radiotherapy quality assurance processes is merited.
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Affiliation(s)
- Emma R Biglin
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, 3rd floor Proton Beam Therapy Centre, Oak Road, Manchester, M20 4BX, UK.
| | - Adam H Aitkenhead
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, 3rd floor Proton Beam Therapy Centre, Oak Road, Manchester, M20 4BX, UK
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
| | - Gareth J Price
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, 3rd floor Proton Beam Therapy Centre, Oak Road, Manchester, M20 4BX, UK
- The Christie NHS Foundation Trust, Manchester, UK
| | - Amy L Chadwick
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, 3rd floor Proton Beam Therapy Centre, Oak Road, Manchester, M20 4BX, UK
- The Christie NHS Foundation Trust, Manchester, UK
| | - Elham Santina
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, 3rd floor Proton Beam Therapy Centre, Oak Road, Manchester, M20 4BX, UK
- The Christie NHS Foundation Trust, Manchester, UK
| | - Kaye J Williams
- Division of Pharmacy and Optometry, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Karen J Kirkby
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, 3rd floor Proton Beam Therapy Centre, Oak Road, Manchester, M20 4BX, UK
- The Christie NHS Foundation Trust, Manchester, UK
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40
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Cavallone M, Jorge PG, Moeckli R, Bailat C, Flacco A, Prezado Y, Delorme R. Determination of the ion collection efficiency of the Razor Nano Chamber for ultra-high dose-rate electron beams. Med Phys 2022; 49:4731-4742. [PMID: 35441716 PMCID: PMC9539950 DOI: 10.1002/mp.15675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 04/07/2022] [Accepted: 04/12/2022] [Indexed: 11/10/2022] Open
Abstract
Background Ultra‐high dose‐rate (UHDR) irradiations (>40 Gy/s) have recently garnered interest in radiotherapy (RT) as they can trigger the so‐called “FLASH” effect, namely a higher tolerance of normal tissues in comparison with conventional dose rates when a sufficiently high dose is delivered to the tissue. To transfer this to clinical RT treatments, adapted methods and practical tools for online dosimetry need to be developed. Ionization chambers remain the gold standards in RT but the charge recombination effects may be very significant at such high dose rates, limiting the use of some of these dosimeters. The reduction of the sensitive volume size can be an interesting characteristic to reduce such effects. Purpose In that context, we have investigated the charge collection behavior of the recent IBA Razor™ Nano Chamber (RNC) in UHDR pulses to evaluate its potential interest for FLASH RT. Methods In order to quantify the RNC ion collection efficiency (ICE), simultaneous dose measurements were performed under UHDR electron beams with dose‐rate‐independent Gafchromic™ EBT3 films that were used as the dose reference. A dose‐per‐pulse range from 0.01 to 30 Gy was investigated, varying the source‐to‐surface distance, the pulse duration (1 and 3 μs investigated) and the LINAC gun grid tension as irradiation parameters. In addition, the RNC measurements were corrected from the inherent beam shot‐to‐shot variations using an independent current transformer. An empirical logistic model was used to fit the RNC collection efficiency measurements and the results were compared with the Advanced Markus plane parallel ion chamber. Results The RNC ICE was found to decrease as the dose‐per‐pulse increases, starting from doses above 0.2 Gy/pulse and down to 40% of efficiency at 30 Gy/pulse. The RNC resulted in a higher ICE for a given dose‐per‐pulse in comparison with the Markus chamber, with a measured efficiency found higher than 85 and 55% for 1 and 10 Gy/pulse, respectively, whereas the Markus ICE was of 60 and 25% for the same doses. However, the RNC shows a higher sensitivity to the pulse duration than the Advanced Markus chamber, with a lower efficiency found at 1 μs than at 3 μs, suggesting that this chamber could be more sensitive to the dose rate within the pulse. Conclusions The results confirmed that the small sensitive volume of the RNC ensures higher ICE compared with larger chambers. The RNC was thus found to be a promising online dosimetry tool for FLASH RT and we proposed an ion recombination model to correct its response up to extreme dose‐per‐pulses of 30 Gy.
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Affiliation(s)
- Marco Cavallone
- Institut Curie, PSL Research University, Radiation Oncology Department, Proton Therapy Centre, Centre Universitaire, Orsay, 91898, France.,Laboratoire d'Optique Appliquée, ENSTA Paris, École Polytechnique, CNRS-UMR7639, Institut Polytechnique de Paris, Palaiseau Cedex, 91762, France
| | | | - Raphaël Moeckli
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland
| | - Alessandro Flacco
- Laboratoire d'Optique Appliquée, ENSTA Paris, École Polytechnique, CNRS-UMR7639, Institut Polytechnique de Paris, Palaiseau Cedex, 91762, France
| | - Yolanda Prezado
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, Orsay, 91400, France.,Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, Orsay, 91400, France
| | - Rachel Delorme
- University of Grenoble Alpes, CNRS, Grenoble INP, LPSC-IN2P3, Grenoble, 38000, France.,Imagerie et Modélisation en Neurobiologie et Cancérologie (IMNC), CNRS Univ Paris-Sud, Université Paris-Saclay, Orsay, F-91400, France
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41
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Valero C, Sarno A, Cutaia C, Poli M, Isoardi P, Stasi M. On the suitability of XR-SP2 gafchromic films for dosimetry in mammography. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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42
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Huang L, Gaballa H, Chang J. Evaluating dosimetric accuracy of the 6 MV calibration on EBT3 film in the use of Ir-192 high dose rate brachytherapy. J Appl Clin Med Phys 2022; 23:e13571. [PMID: 35226398 PMCID: PMC9121041 DOI: 10.1002/acm2.13571] [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: 09/23/2021] [Revised: 02/05/2022] [Accepted: 02/07/2022] [Indexed: 12/03/2022] Open
Abstract
Purpose To evaluate the dosimetric accuracy of EBT3 film calibrated with a 6 MV beam for high dose rate brachytherapy and propose a novel method for direct film calibration with an Ir‐192 source. Methods The 6 MV calibration was performed in water on a linear accelerator (linac). The Ir‐192 calibration was accomplished by irradiating the film wrapped around a cylinder applicator with an Ir‐192 source. All films were scanned 1‐day post‐irradiation to acquire calibration curves for all three (red, blue, and green) channels. The Ir‐192 calibration films were also used for single‐dose comparison. Moreover, an independent test film under a H.A.M. applicator was irradiated and the 2D dose distribution was obtained separately for each calibration using the red channel data. Gamma analysis and point‐by‐point profile comparison were performed to evaluate the performance of both calibrations. The uncertainty budget for each calibration system was analyzed. Results The red channel had the best performance for both calibration systems in the single‐dose comparison. We found a significant 4.89% difference from the reference for doses <250 cGy using the 6 MV calibration, while the difference was only 0.87% for doses >600 cGy. Gamma analysis of the 2D dose distribution showed the Ir‐192 calibration had a higher passing rate of 91.9% for the 1 mm/2% criterion, compared to 83.5% for the 6 MV calibration. Most failing points were in the low‐dose region (<200 cGy). The point‐by‐point profile comparison reported a discrepancy of 2%–3.6% between the Ir‐192 and 6 MV calibrations in this low‐dose region. The linac‐ and Ir‐192‐based dosimetry systems had an uncertainty of 4.1% (k = 2) and 5.66% (k = 2), respectively. Conclusions Direct calibration of EBT3 films with an Ir‐192 source is feasible and reliable, while the dosimetric accuracy of 6 MV calibration depends on the dose range. The Ir‐192 calibration should be used when the measurement dose range is below 250 cGy.
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Affiliation(s)
- Lyu Huang
- Department of Radiation Medicine, Center for Advanced Medicine, Northwell Health, New Hyde Park, New York, USA
| | - Hani Gaballa
- Department of Radiation Medicine, Center for Advanced Medicine, Northwell Health, New Hyde Park, New York, USA
| | - Jenghwa Chang
- Department of Radiation Medicine, Center for Advanced Medicine, Northwell Health, New Hyde Park, New York, USA.,Department of Radiation Medicine, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, New Hyde Park, New York, USA.,Department of Physics and Astronomy, Hofstra University, Hempstead, New York, USA
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43
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El-Naggar HI, Ghanim E, El Ghazaly M, Salama T. On the registration of low energy alpha particle with modified GafChromic EBT2 radiochromic film. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2021.109852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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44
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45
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Tien CJ, Damast S, Chen ZJ. Dosimetric study of Varian Universal Multi-Channel Cylinder System for High-Dose-Rate 192Ir Brachytherapy. Brachytherapy 2022; 21:244-254. [PMID: 34996715 DOI: 10.1016/j.brachy.2021.11.001] [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: 07/08/2021] [Revised: 11/05/2021] [Accepted: 11/08/2021] [Indexed: 11/28/2022]
Abstract
PURPOSE Recently, the Varian multichannel vaginal cylinder (MCVC) set for high-dose-rate 192Ir brachytherapy was commercially released. This MCVC was distinct from our existing MCVC in its peripheral channel layout and tip design. This investigation sought to assess the dosimetric impact of these changes. METHODS AND MATERIALS The dimensions of the virtual model for each applicator were compared against both physical and radiographic measurements. Volumetric dose distributions were generated in silico using a model-based dose calculation algorithm (MBDCA). To characterize the effects of the new peripheral channel layout on dose to adjacent areas ("dose-spill"), point doses were compared using two sets of applicator-based reference points: at surface or 5 mm radially from surface. To evaluate the dose-shaping capabilities, a dose distribution was generated for the new applicator and assessed against a representative dose distribution for a patient previously treated with existing equipment. RESULTS Based on both physical and radiographic measurements, virtual models were representative of each applicator within ±1 mm. Commissioning of the MBDCA was benchmarked based on AAPM Working Group on Dose Calculation Algorithms in Brachytherapy. The layout of the new applicator reduced dose-spill to other reference points significantly, as much as a factor of 16.3, compared with the existing equipment. The rounded tip shape and curve of the peripheral channels in the new applicator produced more conformity to its HR-CTV than existing equipment. CONCLUSIONS Compared with our existing equipment, the design changes in the new Varian MCVC set offered improved control of dose spill and better conformality to HR-CTV.
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Affiliation(s)
- Christopher J Tien
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT.
| | - Shari Damast
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT
| | - Zhe Jay Chen
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT
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Cook H, Lambert J, Thomas R, Palmans H, Hussein M, Clark CH, Royle G, Pettingell J, Lourenço A. Development of a heterogeneous phantom to measure range in clinical proton therapy beams. Phys Med 2022; 93:59-68. [PMID: 34968893 DOI: 10.1016/j.ejmp.2021.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 11/16/2021] [Accepted: 11/20/2021] [Indexed: 11/24/2022] Open
Abstract
PURPOSE In particle therapy, determination of range by measurement or calculation can be a significant source of uncertainty. This work investigates the development of a bespoke Range Length Phantom (RaLPh) to allow independent determination of proton range in tissue. This phantom is intended to be used as an audit device. METHOD RaLPh was designed to be compact and allows different configurations of tissue substitute slabs, to facilitate measurement of range using radiochromic film. Fourteen RaLPh configurations were tested, using two types of proton fluence optimised water substitutes, two types of bone substitute, and one lung substitute slabs. These were designed to mimic different complex tissue interfaces. Experiments were performed using a 115 MeV mono-energetic scanning proton beam to investigate the proton range for each configuration. Validation of the measured film ranges was performed via Monte Carlo simulations and ionisation chamber measurements. The phantom was then assessed as an audit device, by comparing film measurements with Treatment Planning System (TPS) predicted ranges. RESULTS Varying the phantom slab configurations allowed for measurable range differences, and the best combinations of heterogeneous material gave agreement between film and Monte Carlo on average within 0.2% and on average within 0.3% of ionisation chamber measurements. Results against the TPS suggest a material density override is currently required to enable the phantom to be an audit device. CONCLUSION This study found that a heterogeneous phantom with radiochromic film can provide range verification as part of a dedicated audit for clinical proton therapy beams.
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Affiliation(s)
- H Cook
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom; Medical Radiation Science, National Physical Laboratory, Teddington, TW11 0LW, United Kingdom.
| | - J Lambert
- Medical Physics Department, The Rutherford Cancer Centre South Wales, Newport NP10 8FZ, United Kingdom
| | - R Thomas
- Medical Radiation Science, National Physical Laboratory, Teddington, TW11 0LW, United Kingdom
| | - H Palmans
- Medical Radiation Science, National Physical Laboratory, Teddington, TW11 0LW, United Kingdom; Medical Physics Group, MedAustron Ion Therapy Center, A-2700 Wiener Neustadt, Austria
| | - M Hussein
- Medical Radiation Science, National Physical Laboratory, Teddington, TW11 0LW, United Kingdom
| | - C H Clark
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom; Medical Radiation Science, National Physical Laboratory, Teddington, TW11 0LW, United Kingdom; Radiotherapy Physics, University College London Hospital, NW1 2BU, United Kingdom; Radiotherapy Trials Quality Assurance Group (RTTQA), Mount Vernon Cancer Centre, HA6 2RN, United Kingdom
| | - G Royle
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
| | - J Pettingell
- Medical Physics Department, The Rutherford Cancer Centre South Wales, Newport NP10 8FZ, United Kingdom
| | - A Lourenço
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom; Medical Radiation Science, National Physical Laboratory, Teddington, TW11 0LW, United Kingdom
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Using magnetic material to repulse electrons in Axxent eBT for skin preservation during early-stage breast cancer conservative intra-operative radiotherapy. J Contemp Brachytherapy 2021; 13:575-582. [PMID: 34759982 PMCID: PMC8565629 DOI: 10.5114/jcb.2021.109933] [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: 02/09/2021] [Accepted: 07/28/2021] [Indexed: 12/03/2022] Open
Abstract
A miniature electronic X-ray source was employed in this study to deliver intra-operative radiotherapy (IORT) within breast lesions. A flexible magnetic material was used to reduce breast skin radiation damage. Total prescribed dose was 20 Gy at balloon surface, with breast tumor bed wrapped around balloon applicator. A flexible magnetic material, called ‘neodymium-iron boron’ (NdFeB) + alloy-49 was applied to cover lesion’s surface to preserve the skin and to reduce electron contamination raised from photon-induced low-energy electrons, with tissue less than 1 cm between applicator surface and breast skin. The reduction of electron contamination using NdFeB + alloy-49 with an applicator-skin distance of 20 mm, ranged from 7% to 10%, while with an applicator-skin distance of 10 mm for balloon volumes from 30 to 50 cm3, it ranged from 4% to 6% only. NdFeB + alloy-49 magnetic material was efficient in repulsing photon-induced low-energy electrons for skin preservation to compensate for deficiency of tissue over less than 1 cm gap between the surface of applicator and the breast skin.
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Characterization of Gafchromic™ film response against radionuclide activity. Appl Radiat Isot 2021; 178:109988. [PMID: 34688025 DOI: 10.1016/j.apradiso.2021.109988] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 10/09/2021] [Accepted: 10/15/2021] [Indexed: 11/23/2022]
Abstract
PURPOSE In this study, we used Gafchromic™ film XR-QA2 and RT-QA2 to characterize the film energy response against various radionuclides. We introduce a neutron depletion theoretical model that can describe film response as a function of cumulated activity. The film response was investigated with respect to different backscatter media such as polystyrene, perspex, lead and corrugated fibreboard carton (CFC). The sensitivity of the two types of film to different energies was also studied. Lastly, a film stack method was tested to allow the user to obtain sequential, cumulative doses at different time points. METHODS Pieces of Gafchromic™ film XR-QA2 and RT-QA2 were exposed to Am-241, Cs-137, Tc-99m, and I-131 to obtain various cumulative activities. After 24 h, each film piece was digitized by scanning it with an Epson Perfection V330 flatbed scanner to obtain 48-bit RGB TIFF images. Afterwards, each image was processed with the Image J software package. The film response was fitted to a theoretically derived function based on the neutron depletion model and the Beer-Lambert Law and compared with an existing fitting function. Layers of the film were also placed together and irradiated with the above-mentioned radionuclides to investigate the possibility of increasing the sensitivity of the film as a dosimeter. The energy response of the two types of film was investigated by irradiating pieces of film with different photon energies. RESULTS The theoretical response model fits OD vs cumulative activity accurately. XR-QA2 film shows good energy film response by using CFC as a backscatter material when using radionuclides. From the results, it is also evident that XR-QA2 is more sensitive to low energy gamma rays than RT-QA2. Its OD sensitivity can be increased by 2 ± 0.2 when using a double layer film and by 2.8 ± 0.3 when using a triple-layer film. By using a film stack, the experimental time can be decreased by using the second-order polynomial relationship obtained to relate the stacked film data to the single film data. CONCLUSIONS The neutron depletion theoretical model is accurate and contains less free parameters than higher-order polynomial fits. The Gafchromic™ XR-QA2 film is also better to use in nuclear medicine because of its higher sensitivity. The sensitivity of the film as a dosimeter can also be increased by using multiple layers of film. Experiment times can also be decreased by using the film stack method.
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Safaeipour E, Poorbaygi H, Jabbari I, Sheibani S. Evaluation of dosimetric functions for a new 169 Yb HDR Brachytherapy Source. J Appl Clin Med Phys 2021; 22:82-93. [PMID: 34263515 PMCID: PMC8425858 DOI: 10.1002/acm2.13347] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/17/2020] [Accepted: 06/16/2021] [Indexed: 11/30/2022] Open
Abstract
169 Yb has been recently used as an HDR brachytherapy source for cancer treatment. In this paper, dosimetric parameters of a new design of 169 Yb HDR brachytherapy source were determined by Monte Carlo (MC) method and film dosimetry. In this new source, the radioactive core has been encapsulated twice for safety purposes. The calculations of dosimetric parameters carried out using MC simulation in water and air phantom. In order to exclude photon contamination's cutoff energy, δ was set at 10 keV. TG-43U1 data dosimetric, including Sk , Λ, g(r), F(r, θ) was computed using outputs from the simulation and their statistical uncertainties were calculated. Dose distribution around the new prototype source in PMMA phantom in the framework of AAPM TG-43 and TG-55 recommendations was measured by Radiochromic film (RCF) Gafchromic EBT3. Obtained air kerma strength, Sk , and the dose rate constant, Λ, from simulation has a value of 1.03U ± 0.03 and 1.21 cGyh-1 U-1 ± 0.03, respectively. The radial dose function was calculated at radial distances between 0.5 and 10 cm with a maximum value of 1.15 ± 0.03 at 5-6 cm distances. The anisotropy functions for radial distances of 0.5-7 cm and angle distances 0° to180° were calculated. The dosimetric data of the new HDR 169 Yb source were compared with another reference source of 169 Yb-HDR and were found that has acceptable compatibility. In addition, the anisotropy function of the MC simulation and film dosimetry method at a distance of 1 cm from this source was obtained and a good agreement was found between the anisotropy results.
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Affiliation(s)
- Elham Safaeipour
- Department of Nuclear EngineeringFaculty of Advanced Science & TechnologiesUniversity of IsfahanIsfahanIran
| | - Hosein Poorbaygi
- Radiation Application Research SchoolNuclear Science and Technology Research InstituteTehranIran
| | - Iraj Jabbari
- Department of Nuclear EngineeringFaculty of Advanced Science & TechnologiesUniversity of IsfahanIsfahanIran
| | - Shahab Sheibani
- Radiation Application Research SchoolNuclear Science and Technology Research InstituteTehranIran
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Dubus F, Reynaert N. Dose calculation validation of a convolution algorithm in a solid water phantom. Phys Med 2021; 89:193-199. [PMID: 34392102 DOI: 10.1016/j.ejmp.2021.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 07/21/2021] [Accepted: 08/03/2021] [Indexed: 11/20/2022] Open
Abstract
PURPOSE The dose calculated using a convolution algorithm should be validated in a simple homogeneous water-equivalent phantom before clinical use. The dose calculation accuracy within a solid water phantom was investigated. METHODS The specific Gamma knife design requires a dose rate calibration within a spherical solid water phantom. The TMR10 algorithm, which approximates the phantom material as liquid water, correctly computes the absolute dose in water. The convolution algorithm, which considers electron density miscalculates the dose in water as the phantom Hounsfield units were converted into higher electron density when the original CT calibration curve was used. To address this issue, the electron density of liquid water was affected by modifying the CT calibration curve. The absolute dose calculated using the convolution algorithm was compared with that computed by the TMR10. The measured depth dose profiles were also compared to those computed by the convolution and TMR10 algorithms. A patient treatment was recalculated in the solid-water phantom and the delivery quality assurance was checked. RESULTS The convolution algorithm and the TMR10 calculate an absolute dose within 1% when using the modified CT calibration curve. The dose depth profile calculated using the convolution algorithms was superimposed on the TMR10 and measured dose profiles when the modified CT calibration curve was applied. The Gamma index was better than 93%. CONCLUSIONS Dose calculation algorithms, which consider electron density, require a CT calibration curve adapted to the phantom material to correctly compute the dose in water.
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Affiliation(s)
- François Dubus
- Medical Physics Department, University Hospital, Lille, France.
| | - Nick Reynaert
- Medical Physics Department, Centre Bordet, Brussels, Belgium
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