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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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2
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Saße K, Albers K, Klassen PD, Marianyagam NJ, Weidlich G, Schneider MB, Chang S, Adler J, Poppe B, Looe HK, Eulenstein D. Experimental and Monte Carlo based dosimetric investigation of a novel 3 mm radiosurgery 3 MV beam using the microSilicon detector. J Appl Clin Med Phys 2024; 25:e14388. [PMID: 38762906 PMCID: PMC11163500 DOI: 10.1002/acm2.14388] [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: 03/15/2024] [Accepted: 04/15/2024] [Indexed: 05/21/2024] Open
Abstract
BACKGROUND The ZAP-X system is a novel gyroscopic radiosurgical system based on a 3 MV linear accelerator and collimator cones with a diameter between 4 and 25 mm. Advances in imaging modalities to detect small and early-stage pathologies allow for an early and less invasive treatment, where a smaller collimator matching the anatomical target could provide better sparing of surrounding healthy tissue. PURPOSE A novel 3 mm collimator cone for the ZAP-X was developed. This study aims to investigate the usability of a commercial diode detector (microSilicon) for the dosimetric characterization of this small collimator cone; and to investigate the underlying small field perturbation effects. METHODS Profile measurements in five depths as well as PDD and output ratio measurements were performed with a microSilicon detector and radiochromic EBT3 films. In addition, comprehensive Monte Carlo simulations were performed to validate the measurement observations and to quantify the perturbation effects of the microSilicon detector in these extremely small field conditions. RESULTS It is shown that the microSilicon detector enables an accurate dosimetric characterization of the 3 mm beam. The profile parameters, such as the FWHM and 20%-80% penumbra width, agree within 0.1 to 0.2 mm between film and detector measurements. The output ratios agree within the measurement uncertainty between microSilicon detector and films, whereas the comparisons of the PDD results show good agreement with the Monte Carlo simulations. The analysis of the perturbation factors of the microSilicon detector reveals a small field correction factor of approximately 3% for the 3 mm circular beam and a correction factor smaller than 1.5% for field diameters above 3 mm. CONCLUSIONS It could be shown that the microSilicon detector is well-suitable for the characterization of the new 3 mm circular beam of the ZAP-X system.
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Affiliation(s)
- Katrin Saße
- University Clinic for Medical Radiation Physics, Medical Campus Pius HospitalCarl von Ossietzky UniversityOldenburgGermany
| | - Karina Albers
- University Clinic for Medical Radiation Physics, Medical Campus Pius HospitalCarl von Ossietzky UniversityOldenburgGermany
| | | | - Neelan J. Marianyagam
- Department of NeurosurgeryStanford University School of MedicinePalo AltoCaliforniaUSA
| | | | | | - Steven Chang
- Department of NeurosurgeryStanford University School of MedicinePalo AltoCaliforniaUSA
| | - John Adler
- ZAP Surgical SystemsSan CarlosCaliforniaUSA
| | - Björn Poppe
- University Clinic for Medical Radiation Physics, Medical Campus Pius HospitalCarl von Ossietzky UniversityOldenburgGermany
| | - Hui Khee Looe
- University Clinic for Medical Radiation Physics, Medical Campus Pius HospitalCarl von Ossietzky UniversityOldenburgGermany
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Miura H, Miyazawa M, Ozawa S, Enosaki T, Kagemoto M. Lateral response artifact correction method using image stitching technique in radiochromic film dosimetry. J Appl Clin Med Phys 2024:e14373. [PMID: 38696704 DOI: 10.1002/acm2.14373] [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: 08/27/2023] [Revised: 04/01/2024] [Accepted: 04/13/2024] [Indexed: 05/04/2024] Open
Abstract
PURPOSE Lateral response artifact (LRA) is caused by the interaction between film and flatbed scanner in the direction perpendicular to the scanning direction. This can significantly affect the accuracy of patient-specific quality assurance (QA) in cases involving large irradiation fields. We hypothesized that by utilizing the central area of the flatbed scanner, where the magnitude of LRA is relatively small, the LRA could be mitigated effectively. This study proposes a practical solution using the image-stitching technique to correct LRA for patient-specific QA involving large irradiation fields. METHODS Gafchromic™ EBT4 film and Epson Expression ES-G11000 flatbed scanner were used in this study. The image-stitching algorithm requires a spot between adjacent images to combine them. The film was scanned at three locations on a flatbed scanner, and these images were combined using the image-stitching technique. The combined film dose was then calculated and compared with the treatment planning system (TPS)-calculated dose using gamma analysis (3%/2 mm). Our proposed LRA correction was applied to several films exposed to 18 × 18 cm2 open fields at doses of 200, 400, and 600 cGy, as well as to four clinical Volumetric Modulated Arc Therapy (VMAT) treatment plans involving large fields. RESULTS For doses of 200, 400, and 600 cGy, the gamma analysis values with and without LRA corrections were 95.7% versus 67.8%, 95.5% versus 66.2%, and 91.8% versus 35.9%, respectively. For the clinical VMAT treatment plan, the average pass rate ± standard deviation in gamma analysis was 94.1% ± 0.4% with LRA corrections and 72.5% ± 1.5% without LRA corrections. CONCLUSIONS The effectiveness of our proposed LRA correction using the image-stitching technique was demonstrated to significantly improve the accuracy of patient-specific QA for VMAT treatment plans involving large irradiation fields.
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Affiliation(s)
- Hideharu Miura
- Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan
- Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan
| | | | - Shuichi Ozawa
- Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan
- Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Tsubasa Enosaki
- Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan
| | - Masayuki Kagemoto
- Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan
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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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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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Miura H, Ozawa S, Okazue T, Enosaki T, Nagata Y. Characterization of scanning orientation and lateral response artifact for EBT4 Gafchromic film. J Appl Clin Med Phys 2023:e13992. [PMID: 37086445 PMCID: PMC10402671 DOI: 10.1002/acm2.13992] [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: 01/16/2023] [Revised: 03/29/2023] [Accepted: 04/04/2023] [Indexed: 04/24/2023] Open
Abstract
The purpose of this study was to investigate the impact of scanning orientation and lateral response artifact (LRA) effects on the dose-response of EBT4 films and compare it with that of EBT3 films. Dose-response curves for EBT3 and EBT4 films in red-green-blue (RGB) color channels in portrait orientation were created for unexposed films and for films exposed to doses ranging from 0 to 1 000 cGy. Portrait and landscape orientations of the EBT3 and EBT4 films were scanned to investigate the scanning orientation effect in the red channel. EBT3 and EBT4 films were irradiated to assess the LRA in the red channel using a field size of 15 × 15 cm2 and delivered doses of 200, 400, and 600 cGy. Films were scanned at the edge of the scanner bed, and the measured doses were compared with the treatment planning system (TPS) calculated doses at a position 100 mm lateral to the scanner center. At a dose of 200 cGy, the differences in optical density (OD) in the red, green, and blue color channels between EBT3 and EBT4 films were 0.035 (24.8%), 0.042 (49.7%), and 0.022 (64.4%), respectively. The EBT4 film slightly improved the scanning orientation compared to the EBT3 film. The OD difference in the different scanning orientations for the EBT3 and EBT4 films was 0.015 (6.8%) and 0.007 (3.9%), respectively, at a dose of 200 cGy. This is equivalent to a 20 or 10 cGy variation at a dose of 200 cGy. Compared with the TPS calculation, the measurement doses for EBT3 and EBT4 films irradiated at 200 cGy were approximately 16% and 13% higher, respectively, at the 100 mm off-centered position. The EBT4 film showed an improvement concerning the impact of LRA compared with the EBT3 film. This study demonstrated that the response of EBT4 film to a dose in the blue channel was less sensitive and showed an improvement in the scanning orientation and LRA effects.
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Affiliation(s)
- Hideharu Miura
- Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan
- Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Shuichi Ozawa
- Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan
- Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Toshiya Okazue
- Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan
| | - Tsubasa Enosaki
- Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan
| | - Yasushi Nagata
- Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan
- Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan
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Shameem T, Bennie N, Butson M, Thwaites D. Effect of scanner lens on lateral response artefact in radiochromic film dosimetry. Phys Eng Sci Med 2022; 45:721-727. [PMID: 35635609 PMCID: PMC9448687 DOI: 10.1007/s13246-022-01136-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 05/03/2022] [Indexed: 11/28/2022]
Abstract
Radiochromic film is a good dosimeter choice for patient QA for complex treatment techniques because of its near tissue equivalency, high spatial resolution and established method of use. Commercial scanners are typically used for film dosimetry, with Epson scanners being the most common. Radiochromic film dosimetry is not straightforward having some well-defined problems which must be considered, one of the main ones being the Lateral Response Artefact (LRA) effect. Previous studies showed that the contributing factors to LRA are from the structure of the active ingredients of the film and the components and construction of the flatbed scanner. This study investigated the effect of the scanner lens on the LRA effect, as part of a wider investigation of scanner design effects and uncertainties. Gafchromic EBT3 films were irradiated with 40 × 40 cm2 field size 6 MV beams. Films were analysed using images captured by a Canon 7D camera utilising 18 mm, 50 mm and 100 mm focal length lenses compared to images scanned with a conventional Epson V700 scanner. The magnitude of the LRA was observed to be dependent on the focal length of the lens used to image the film. A substantial reduction in LRA was seen with the use of the 50 mm and 100 mm lenses, by factors of 3–5 for the 50 mm lens and 4–30 for the 100 mm lens compared to conventional desktop scanner techniques. This is expected to be from the longer focal length camera lens system being able to collect more light from distant areas compared to the scanner-based system. This provides an opportunity to design film dosimetry systems that minimise this artefact.
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Affiliation(s)
- Tarafder Shameem
- North Coast Cancer Institute, Lismore, NSW, Australia.
- Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW, Australia.
| | - Nick Bennie
- North Coast Cancer Institute, Lismore, NSW, Australia
| | - Martin Butson
- Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW, Australia
- EPA, Sydney, NSW, Australia
| | - David Thwaites
- Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW, Australia
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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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Ono K, Fujino K, Kurihara R, Hayashi SI, Akagi Y, Hirokawa Y. Three-dimensional Winston-Lutz test using reusable polyvinyl alcohol-iodide (PVA-I) radiochromic gel dosimeter. Phys Med Biol 2021; 66. [PMID: 34530407 DOI: 10.1088/1361-6560/ac279d] [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: 05/26/2021] [Accepted: 09/16/2021] [Indexed: 01/01/2023]
Abstract
Medical linear-accelerator-based stereotactic radiosurgery (SRS) using a stereotactic apparatus or image-guided radiotherapy system for intracranial lesions is performed widely in clinical practice. In general, Winston-Lutz (WL) tests using films or electric portal imaging devices (EPIDs) have been performed as pre-treatment and routine quality assurance (QA) for the abovementioned treatment. Two-dimensional displacements between the radiation isocentre and mechanical isocentre are analysed from the test; therefore, it is difficult to identify the three-dimensional (3D) isocentre position intuitively. In this study, we developed an innovative 3D WL test for SRS-QA using a novel radiochromic gel dosimeter based on a polyvinyl alcohol-iodide (PVA-I) complex that can be reused after annealing. A WL gel phantom that was consisted of the PVA-I gel dosimeter poured into a tall acrylic container and an embedded small tungsten sphere was used as a position detector. A flatbed scanner was used to analyse the isocentre position. The measured 3D isocentre accuracy from the gel-based WL test was within 0.1 mm compared with that obtained from the EPID-based WL test. Furthermore, excellent reusability of the WL gel phantom was observed in long-term SRS isocentre verification, in which clinical SRS cases involving repeated irradiation and annealing were analysed. These results demonstrate the high accuracy and reliable evaluation of the isocentre position using an innovative test. In addition, the clinical-based routine SRS-QA using the PVA-I gel dosimeter demonstrates a highly convenience while affording an easy and fast analysis process.
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Affiliation(s)
- Kaoru Ono
- High-precision Radiotherapy Center, Hiroshima Heiwa Clinic, Japan
| | - Keisuke Fujino
- High-precision Radiotherapy Center, Hiroshima Heiwa Clinic, Japan
| | - Ryosuke Kurihara
- High-precision Radiotherapy Center, Hiroshima Heiwa Clinic, Japan
| | | | - Yukio Akagi
- High-precision Radiotherapy Center, Hiroshima Heiwa Clinic, Japan
| | - Yutaka Hirokawa
- High-precision Radiotherapy Center, Hiroshima Heiwa Clinic, Japan
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Méndez I, Rovira-Escutia JJ, Casar B. A protocol for accurate radiochromic film dosimetry using Radiochromic.com. Radiol Oncol 2021; 55:369-378. [PMID: 34384012 PMCID: PMC8366735 DOI: 10.2478/raon-2021-0034] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 07/01/2021] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Radiochromic films have many applications in radiology and radiation therapy. Generally, the dosimetry system for radiochromic film dosimetry is composed of radiochromic films, flatbed scanner, and film analysis software. The purpose of this work is to present the effectiveness of a protocol for accurate radiochromic film dosimetry using Radiochromic.com as software for film analysis. MATERIALS AND METHODS Procedures for image acquisition, lot calibration, and dose calculation are explained and analyzed. Radiochromic.com enables state-of-the-art models and corrections for radiochromic film dosimetry, such as the Multigaussian model for multichannel film dosimetry, and lateral, inter-scan, and re-calibration corrections of the response. RESULTS The protocol presented here provides accurate dose results by mitigating the sources of uncertainty that affect radiochromic film dosimetry. CONCLUSIONS Appropriate procedures for film and scanner handling in combination with Radiochromic.com as software for film analysis make easy and accurate radiochromic film dosimetry feasible.
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Affiliation(s)
- Ignasi Méndez
- Department for dosimetry and quality of radiological procedures, Institute of Oncology Ljubljana, Ljubljana, Slovenia
| | | | - Bozidar Casar
- Department for dosimetry and quality of radiological procedures, Institute of Oncology Ljubljana, Ljubljana, Slovenia
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Development and dosimetric characterization of novel amide substituted diacetylene based radiochromic films for medical radiation dosimetry. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2021.109391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Radiochromic Films for the Two-Dimensional Dose Distribution Assessment. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11052132] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Radiochromic films are mainly used for two-dimensional dose verification in photon, electron, and proton therapy treatments. Moreover, the radiochromic film types available today allow their use in a wide dose range, corresponding to applications from low-medical diagnostics to high-dose beam profile measurements in charged particle medical accelerators. An in-depth knowledge of the characteristics of radiochromic films, of their operating principles, and of the dose reading techniques is of paramount importance to exploit all the features of this interesting and versatile radiation detection system. This short review focuses on these main aspects by considering the most recent works on the subject.
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Santos T, Ventura T, Lopes MDC. A review on radiochromic film dosimetry for dose verification in high energy photon beams. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2020.109217] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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14
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Rodríguez C, López-Fernández A, García-Pinto D. A new approach to radiochromic film dosimetry based on non-local means. Phys Med Biol 2020; 65:225019. [PMID: 33200749 DOI: 10.1088/1361-6560/abb71b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Radiochromic film in conjunction with flatbed scanners are frequently employed as dosimeters for advanced techniques in radiotherapy. Their strengths are as follows: light element composition, low energy dependence, near biological tissue equivalence and high spatial resolution. However, they have some weaknesses as well: non-uniformities, read out noise, and scanning artifacts. Several processing protocols have been proposed intending to correct the perturbations these weaknesses produce. The aim of this paper is to present a new processing protocol for radiochromic film dosimetry based on a non-local means denoising algorithm. Three dose distributions of open square fields and a spatial combination of these fields using different angles of incidence and monitor units have been employed to validate the protocol. The dose distributions are traceable to ionization chamber measurements. Additionally, a real dose distribution of a treatment was used to simulate scanning data with noise and scanning lateral artifact, and to study how the protocol behaves under these perturbations. The same measured raw data have been processed by means of an implementation of the multichannel protocol (multigaussian method). It has been found that the proposed protocol reduces dose uncertainty even though it uses fewer scans than the multichannel protocol.
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Affiliation(s)
- César Rodríguez
- Medical Physics and Radiation Protection Service, Fuenlabrada University Hospital, Fuenlabrada, Spain. Medical Physics, Radiology Department, Complutense University, Madrid, Spain
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Niroomand‐Rad A, Chiu‐Tsao S, Grams MP, Lewis DF, Soares CG, Van Battum LJ, Das IJ, Trichter S, Kissick MW, Massillon‐JL G, Alvarez PE, Chan MF. Report of AAPM Task Group 235 Radiochromic Film Dosimetry: An Update to TG‐55. Med Phys 2020; 47:5986-6025. [DOI: 10.1002/mp.14497] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 09/15/2020] [Accepted: 09/17/2020] [Indexed: 12/12/2022] Open
Affiliation(s)
| | | | | | | | | | | | - Indra J. Das
- Radiation Oncology Northwestern University Memorial Hospital Chicago IL USA
| | - Samuel Trichter
- New York‐Presbyterian HospitalWeill Cornell Medical Center New York NY USA
| | | | - Guerda Massillon‐JL
- Instituto de Fisica Universidad Nacional Autonoma de Mexico Mexico City Mexico
| | - Paola E. Alvarez
- Imaging and Radiation Oncology Core MD Anderson Cancer Center Houston TX USA
| | - Maria F. Chan
- Memorial Sloan Kettering Cancer Center Basking Ridge NJ USA
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Howard ME, Herman MG, Grams MP. Methodology for radiochromic film analysis using FilmQA Pro and ImageJ. PLoS One 2020; 15:e0233562. [PMID: 32437474 PMCID: PMC7241712 DOI: 10.1371/journal.pone.0233562] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 05/07/2020] [Indexed: 11/23/2022] Open
Abstract
Radiochromic film (RCF) has several advantageous characteristics which make it an attractive dosimeter for many clinical tasks in radiation oncology. However, knowledge of and strict adherence to complicated protocols in order to produce accurate measurements can prohibit RCF from being widely adopted in the clinic. The purpose of this study was to outline some simple and straightforward RCF fundamentals in order to help clinical medical physicists perform accurate RCF measurements. We describe a process and methodology successfully used in our practice with the hope that it saves time and effort for others when implementing RCF in their clinics. Two RCF analysis software programs which differ in cost and complexity, the commercially available FilmQA Pro package and the freely available ImageJ software, were used to show the accuracy, consistency and limitations of each. The process described resulted in a majority of the measurements across a wide dose range to be accurate within ± 2% of the intended dose using either FilmQA Pro or ImageJ.
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Affiliation(s)
- Michelle E. Howard
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Michael G. Herman
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Michael P. Grams
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota, United States of America
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Rose MS, Tirpak L, Van Casteren K, Zack J, Simon T, Schoenfeld A, Simon W. Multi‐institution validation of a new high spatial resolution diode array for SRS and SBRT plan pretreatment quality assurance. Med Phys 2020; 47:3153-3164. [DOI: 10.1002/mp.14153] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 02/20/2020] [Accepted: 03/12/2020] [Indexed: 12/31/2022] Open
Affiliation(s)
- Mark S. Rose
- Sun Nuclear Corporation 3275 Suntree Blvd Melbourne Florida 32940 USA
| | - Lena Tirpak
- Sun Nuclear Corporation 3275 Suntree Blvd Melbourne Florida 32940 USA
| | | | - Jeff Zack
- Sun Nuclear Corporation 3275 Suntree Blvd Melbourne Florida 32940 USA
| | - Tom Simon
- Sun Nuclear Corporation 3275 Suntree Blvd Melbourne Florida 32940 USA
| | | | - William Simon
- Sun Nuclear Corporation 3275 Suntree Blvd Melbourne Florida 32940 USA
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Shameem T, Bennie N, Butson M, Thwaites D. A comparison between EPSON V700 and EPSON V800 scanners for film dosimetry. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2020; 43:10.1007/s13246-019-00837-3. [PMID: 31912461 DOI: 10.1007/s13246-019-00837-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Accepted: 12/16/2019] [Indexed: 11/29/2022]
Abstract
Radiochromic film is a good dosimeter choice for patient QA for complex treatment techniques (IMRT, VMAT, SABR, SBRT) because of its near tissue equivalency, very high spatial resolution and established method of use. Commercial scanners are usually used for film dosimetry, among which EPSON scanners are the most common. NCCI have used an EPSON V700 scanner, but recently acquired a new model EPSON V800 scanner. The purpose of this work was to evaluate any differences between these two scanners to consider whether they can be used interchangeably or not. Different aspects of film dosimetry, e.g. lateral response artefact (LRA) effect, orientation effect, scanner response etc., were compared. EBT3 films were irradiated with 40 × 40 cm2 field size 6 MV beams and scanned in both the scanners. The scanned images were read in ImageJ V1.49 software. The data obtained was then copied in MS Excel to compare the scanners. The V800 scanner causes more polarisation, which results in more LRA effect than for the V700 scanner. The responses of the scanners in all three colour channels are not the same for the same film and irradiation. The V800 scanner shows an increase of response of up to 1.6% compared to 3.7% increase in the V700 scanner after scanning a piece of irradiated film 20 times. The scanners cannot be used interchangeably. The correction factors for LRA effect and the calibration curves are different. Further characterisation, evaluation and commissioning is required before clinical use.
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Affiliation(s)
- Tarafder Shameem
- North Coast Cancer Institute, Lismore, NSW, Australia.
- School of Physics, Institute of Medical Physics, University of Sydney, Sydney, NSW, Australia.
| | - Nick Bennie
- North Coast Cancer Institute, Lismore, NSW, Australia
| | - Martin Butson
- School of Physics, Institute of Medical Physics, University of Sydney, Sydney, NSW, Australia
- Department of Radiation Oncology, Chris O'Brien Lifehouse, Sydney, NSW, Australia
| | - David Thwaites
- School of Physics, Institute of Medical Physics, University of Sydney, Sydney, NSW, Australia
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Padilla-Cabal F, Alejandro Fragoso J, Franz Resch A, Georg D, Fuchs H. Benchmarking a GATE/Geant4 Monte Carlo model for proton beams in magnetic fields. Med Phys 2019; 47:223-233. [PMID: 31661559 PMCID: PMC7003833 DOI: 10.1002/mp.13883] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 10/23/2019] [Accepted: 10/24/2019] [Indexed: 12/16/2022] Open
Abstract
Purpose Magnetic resonance guidance in proton therapy (MRPT) is expected to improve its current performance. The combination of magnetic fields with clinical proton beam lines poses several challenges for dosimetry, treatment planning and dose delivery. Proton beams are deflected by magnetic fields causing considerable changes in beam trajectories and also a retraction of the Bragg peak positions. A proper prediction and compensation of these effects is essential to ensure accurate dose calculations. This work aims to develop and benchmark a Monte Carlo (MC) beam model for dose calculation of MRPT for static magnetic fields up to 1 T. Methods Proton beam interactions with magnetic fields were simulated using the GATE/Geant4 toolkit. The transport of charged particle in custom 3D magnetic field maps was implemented for the first time in GATE. Validation experiments were done using a horizontal proton pencil beam scanning system with energies between 62.4 and 252.7 MeV and a large gap dipole magnet (B = 0–1 T), positioned at the isocenter and creating magnetic fields transverse to the beam direction. Dose was measured with Gafchromic EBT3 films within a homogeneous PMMA phantom without and with bone and tissue equivalent material slab inserts. Linear energy transfer (LET) quenching of EBT3 films was corrected using a linear model on dose‐averaged LET method to ensure a realistic dosimetric comparison between simulations and experiments. Planar dose distributions were measured with the films in two different configurations: parallel and transverse to the beam direction using single energy fields and spread‐out Bragg peaks. The MC model was benchmarked against lateral deflections and spot sizes in air of single beams measured with a Lynx PT detector, as well as dose distributions using EBT3 films. Experimental and calculated dose distributions were compared to test the accuracy of the model. Results Measured proton beam deflections in air at distances of 465, 665, and 1155 mm behind the isocenter after passing the magnetic field region agreed with MC‐predicted values within 4 mm. Differences between calculated and measured beam full width at half maximum (FWHM) were lower than 2 mm. For the homogeneous phantom, measured and simulated in‐depth dose profiles showed range and average dose differences below 0.2 mm and 1.2%, respectively. Simulated central beam positions and widths differed <1 mm to the measurements with films. For both heterogenous phantoms, differences within 1 mm between measured and simulated central beam positions and widths were obtained, confirming a good agreement of the MC model. Conclusions A GATE/Geant4 beam model for protons interacting with magnetic fields up to 1 T was developed and benchmarked to experimental data. For the first time, the GATE/Geant4 model was successfully validated not only for single energy beams, but for SOBP, in homogeneous and heterogeneous phantoms. EBT3 film dosimetry demonstrated to be a powerful dosimetric tool, once the film response function is LET corrected, for measurements in‐line and transverse to the beam direction in magnetic fields. The proposed MC beam model is foreseen to support treatment planning and quality assurance (QA) activities toward MRPT.
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Affiliation(s)
- Fatima Padilla-Cabal
- Department of Radiotherapy, Medical University of Vienna/AKH, Vienna, Austria.,Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria
| | - Jose Alejandro Fragoso
- Department of Nuclear Physics, Higher Institute of Technologies and Applied Science, Havana, Cuba
| | - Andreas Franz Resch
- Department of Radiotherapy, Medical University of Vienna/AKH, Vienna, Austria.,Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria
| | - Dietmar Georg
- Department of Radiotherapy, Medical University of Vienna/AKH, Vienna, Austria.,Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria
| | - Hermann Fuchs
- Department of Radiotherapy, Medical University of Vienna/AKH, Vienna, Austria.,Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria
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De Roover R, Berghen C, De Meerleer G, Depuydt T, Crijns W. Extended field radiotherapy measurements in a single shot using a BaFBr-based OSL-film. ACTA ACUST UNITED AC 2019; 64:165007. [DOI: 10.1088/1361-6560/ab2eff] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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21
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Darafsheh A, León-Marroquín EY, Mulrow DJ, Baradaran-Ghahfarokhi M, Zhao T, Khan R. On the spectral characterization of radiochromic films irradiated with clinical proton beams. ACTA ACUST UNITED AC 2019; 64:135016. [DOI: 10.1088/1361-6560/ab23cd] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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22
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A novel method for EBT3 Gafchromic films read-out at high dose levels. Phys Med 2019; 61:77-84. [DOI: 10.1016/j.ejmp.2019.04.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 04/06/2019] [Accepted: 04/16/2019] [Indexed: 11/24/2022] Open
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23
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Casolaro P, Campajola L, Breglio G, Buontempo S, Consales M, Cusano A, Cutolo A, Di Capua F, Fienga F, Vaiano P. Real-time dosimetry with radiochromic films. Sci Rep 2019; 9:5307. [PMID: 30926839 PMCID: PMC6440967 DOI: 10.1038/s41598-019-41705-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 03/12/2019] [Indexed: 11/20/2022] Open
Abstract
Radiochromic film dosimetry has been widely employed in most of the applications of radiation physics for over twenty years. This is due to a number of appealing features of radiochromic films, such as reliability, accuracy, ease of use and cost. However, current radiochromic film reading techniques, based on the use of commercial densitometers and scanners, provide values of dose only after the exposure of the films to radiation. In this work, an innovative methodology for the real-time reading of radiochromic films is proposed for some specific applications. The new methodology is based on opto-electronic instrumentation that makes use of an optical fiber probe for the determination of optical changes of the films induced by radiation and allows measurements of dose with high degree of precision and accuracy. Furthermore, it has been demonstrated that the dynamic range of some kinds of films, such as the EBT3 Gafchromic films (intensively used in medical physics), can be extended by more than one order of magnitude. Owing to the numerous advantages with respect to the commonly used reading techniques, a National Patent was filed in January 2018.
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Affiliation(s)
- Pierluigi Casolaro
- University of Napoli Federico II, Department of Physics, I-80126, Napoli, Italy.
- Istituto Nazionale di Fisica Nucleare (INFN) - Sezione di Napoli, I-80126, Napoli, Italy.
| | - Luigi Campajola
- University of Napoli Federico II, Department of Physics, I-80126, Napoli, Italy
- Istituto Nazionale di Fisica Nucleare (INFN) - Sezione di Napoli, I-80126, Napoli, Italy
| | - Giovanni Breglio
- University of Napoli Federico II, Department of Electronical Engineering, I-80125, Napoli, Italy
| | - Salvatore Buontempo
- Istituto Nazionale di Fisica Nucleare (INFN) - Sezione di Napoli, I-80126, Napoli, Italy
| | - Marco Consales
- Optoelectronics Group - Department of Engineering, University of Sannio, I-82100, Benevento, Italy.
| | - Andrea Cusano
- Optoelectronics Group - Department of Engineering, University of Sannio, I-82100, Benevento, Italy
| | - Antonello Cutolo
- Optoelectronics Group - Department of Engineering, University of Sannio, I-82100, Benevento, Italy
| | - Francesco Di Capua
- University of Napoli Federico II, Department of Physics, I-80126, Napoli, Italy
- Istituto Nazionale di Fisica Nucleare (INFN) - Sezione di Napoli, I-80126, Napoli, Italy
| | - Francesco Fienga
- Istituto Nazionale di Fisica Nucleare (INFN) - Sezione di Napoli, I-80126, Napoli, Italy
| | - Patrizio Vaiano
- Optoelectronics Group - Department of Engineering, University of Sannio, I-82100, Benevento, Italy
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Abstract
The change in optical properties of GafChromic films depends not only on the absorbed dose, but also on the linear energy transfer (LET) of the ionizing radiation. The influence of LET on the film dose-response relationship is especially important when films are applied for dosimetry of energetic charged particles. In the present study, we examined the response of the unlaminated EBT3 and MD-V3 films to proton, deuterium and helium beams with energies in the range of several megaelectronvolts (MeV). Films were exposed to doses up to 200 Gy and a model based on the bimolecular chemical reaction was chosen to fit the measured film signals. The LET in the active layers of the films and the dose correction factors were computed with Monte Carlo software TRIM. Signal quenching, observed for all ion beams in comparison to x-rays, was investigated as a function of the LET in the range of 10-100 keV µm-1. The response of the films got weaker with increasing the LET and showed no dependence on the ion species. The LET effect was quantified by introducing a modified expression for the relative effectiveness (RE) by which a unique RE value is assigned to a single LET. The RE defined in that way decreased from about 90% for LET of 10 keV µm-1 to less than 50% for LET of 100 keV µm-1. Similar behavior was observed for EBT3 and MD-V3 film models.
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Affiliation(s)
- V. Grilj
- Center for Radiological Research, Columbia University Irving Medical Center, New York, NY, USA
| | - D. J. Brenner
- Center for Radiological Research, Columbia University Irving Medical Center, New York, NY, USA
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25
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Jeang EH, Goh Y, Cho KH, Min S, Choi SH, Jeong H, Jo K, Lee N, Song S, Lee SB, Shin D, Kim YJ, Kim JY, Kim DY, Hwang UJ, Lim YK. Two-dimensional in vivo rectal dosimetry during high-dose-rate brachytherapy for cervical cancer: a phantom study. Acta Oncol 2018; 57:1359-1366. [PMID: 30004264 DOI: 10.1080/0284186x.2018.1484155] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND The aim of the present study was to verify the dosimetric accuracy of two-dimensional (2D) in vivo rectal dosimetry using an endorectal balloon (ERB) with unfoldable EBT3 films for high-dose-rate (HDR) brachytherapy for cervical cancer. The clinical applicability of the technique was discussed. MATERIAL AND METHODS ERB inflation makes the EBT3 films unrolled, whereas its deflation makes them rolled. Patient-specific quality assurance (pQA) tests were performed in 20 patient plans using an Ir-192 remote afterloading system and a water-filled cervical phantom with the ERB. The dose distributions measured in ERBs were compared with those of the treatment plans. RESULTS The absolute dose profiles measured by the ERBs were in good agreement with those of treatment plans. The global gamma passing rates were 96-100% and 91-100% over 20 pQAs under the criteria of 3%/3 mm and 3%/2 mm, respectively, with a 30% low-dose threshold. Dose-volume histograms of the rectal wall were obtained from the measured dose distributions and showed small volume differences less than 2% on average from the patients' plans over the entire dose interval. The positioning error of the applicator set was detectable with high sensitivity of 12% dose area variation per mm. Additionally, the clinical applicability of the ERB was evaluated in volunteers, and none of them felt any pain when the ERB was inserted or removed. CONCLUSIONS The 2D in vivo rectal dosimetry using the ERB with EBT3 films was effective and might be clinically applicable for HDR brachytherapy for cervical and prostate cancers to monitor treatment accuracy and consistency as well as to predict rectal toxicity.
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Affiliation(s)
- Eun Hee Jeang
- Proton Therapy Center, National Cancer Center, Goyang, Korea
| | - Youngmoon Goh
- Proton Therapy Center, National Cancer Center, Goyang, Korea
| | - Kwan Ho Cho
- Proton Therapy Center, National Cancer Center, Goyang, Korea
| | - Soonki Min
- Proton Therapy Center, National Cancer Center, Goyang, Korea
| | - Sang Hyoun Choi
- Department of Radiation Oncology, Korea Cancer Center Hospital, Seoul, Korea
| | - Hojin Jeong
- Department of Radiation Oncology, Gyeongsang National University Hospital, Jinju, Korea
| | - Kwanghyun Jo
- Department of Radiation Oncology, Samsung Medical Center, Seoul, Korea
| | - Nuri Lee
- Proton Therapy Center, National Cancer Center, Goyang, Korea
| | - Sanghyeon Song
- Proton Therapy Center, National Cancer Center, Goyang, Korea
| | - Se Byeong Lee
- Proton Therapy Center, National Cancer Center, Goyang, Korea
| | - Dongho Shin
- Proton Therapy Center, National Cancer Center, Goyang, Korea
| | - Yeon-Joo Kim
- Proton Therapy Center, National Cancer Center, Goyang, Korea
| | - Joo-Young Kim
- Proton Therapy Center, National Cancer Center, Goyang, Korea
| | - Dae Yong Kim
- Proton Therapy Center, National Cancer Center, Goyang, Korea
| | - Ui-Jung Hwang
- Department of Radiation Oncology, National Medical Center, Seoul, Korea
| | - Young Kyung Lim
- Proton Therapy Center, National Cancer Center, Goyang, Korea
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Miguel FJS, Clemente-Gutiérrez F, Pérez-Vara C. Analysis of different procedures for absolute dosimetry with EBT3 radiochromic film. Biomed Phys Eng Express 2018. [DOI: 10.1088/2057-1976/aae1cd] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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27
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Méndez I, Polšak A, Hudej R, Casar B. The Multigaussian method: a new approach to mitigating spatial heterogeneities with multichannel radiochromic film dosimetry. Phys Med Biol 2018; 63:175013. [PMID: 30101754 DOI: 10.1088/1361-6560/aad9c1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The main objective of multichannel radiochromic film dosimetry methods is to correct, or at least mitigate, spatial heterogeneities in the film-scanner response, especially variations in the active layer thickness. To this end, films can also be scanned prior to irradiation. In this study, the abilities of various single channel and multichannel methods to reduce spatial heterogeneities, with and without scanning before irradiation, were tested. Red, green and blue single channel models, two additive channel independent perturbation (CHIP) models and two multiplicative CHIP models were compared with the Multigaussian method. The Multigaussian method is a new approach to multichannel dosimetry, based on experimental findings. It assumes that the probability density function of the response vector formed by the pixel values of the different color channels, including irradiated and non-irradiated scans, follows a multivariate Gaussian distribution. The Multigaussian method provided more accurate doses than the other models under comparison, especially when incorporating the information of the film prior to irradiation. The relative dose differences between reference doses measured with MatriXX and film doses were examined. After applying inter-scan and lateral corrections, the lowest mean absolute errors were 0.8% and 1.0% for the Multigaussian method with and without the information of the scan before irradiation, respectively. Followed by the uniform multiplicative CHIP and red single channel models, using pixel values and net optical density, respectively, both with 1.1%.
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Affiliation(s)
- I Méndez
- Department of Medical Physics, Institute of Oncology Ljubljana, Zaloška cesta 2, Ljubljana 1000, Slovenia
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28
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Barten DLJ, Hoffmans D, Palacios MA, Heukelom S, van Battum LJ. Suitability of EBT3 GafChromic film for quality assurance in MR-guided radiotherapy at 0.35 T with and without real-time MR imaging. ACTA ACUST UNITED AC 2018; 63:165014. [DOI: 10.1088/1361-6560/aad58d] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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29
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Lárraga-Gutiérrez JM, García-Garduño OA, Treviño-Palacios C, Herrera-González JA. Evaluation of a LED-based flatbed document scanner for radiochromic film dosimetry in transmission mode. Phys Med 2018; 47:86-91. [DOI: 10.1016/j.ejmp.2018.02.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 01/28/2018] [Accepted: 02/13/2018] [Indexed: 10/17/2022] Open
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30
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Delfs B, Schoenfeld AA, Poppinga D, Kapsch RP, Jiang P, Harder D, Poppe B, Looe HK. Magnetic fields are causing small, but significant changes of the radiochromic EBT3 film response to 6 MV photons. ACTA ACUST UNITED AC 2018; 63:035028. [DOI: 10.1088/1361-6560/aa9bd5] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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31
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Callens MB, Crijns W, Depuydt T, Haustermans K, Maes F, D’Agostino E, Wevers M, Pfeiffer H, Van Den Abeele K. Modeling the dose dependence of the vis-absorption spectrum of EBT3 GafChromic™ films. Med Phys 2017; 44:2532-2543. [DOI: 10.1002/mp.12246] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 02/16/2017] [Accepted: 03/14/2017] [Indexed: 11/10/2022] Open
Affiliation(s)
- Maarten B. Callens
- Wave Propagation and Signal Processing; KU Leuven - KULAK; Kortrijk 8500 Belgium
| | - Wouter Crijns
- Department of Radiation Oncology; University Hospitals Leuven; Leuven 3000 Belgium
| | - Tom Depuydt
- Department of Radiation Oncology; University Hospitals Leuven; Leuven 3000 Belgium
| | - Karin Haustermans
- Department of Radiation Oncology; University Hospitals Leuven; Leuven 3000 Belgium
| | - Frederik Maes
- Department of Electrical Engineering; ESAT/PSI, KU Leuven; Leuven 3001 Belgium
| | | | - Martine Wevers
- Department of Materials Engineering; KU Leuven; Leuven 3001 Belgium
| | - Helge Pfeiffer
- Department of Materials Engineering; KU Leuven; Leuven 3001 Belgium
| | - Koen Van Den Abeele
- Wave Propagation and Signal Processing; KU Leuven - KULAK; Kortrijk 8500 Belgium
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33
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Wegener S, Sauer OA. Separation of scatter from small MV beams and its effect on detector response. Med Phys 2017; 44:1139-1148. [PMID: 28063164 DOI: 10.1002/mp.12091] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 12/20/2016] [Accepted: 01/01/2017] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Separating the scatter from the primary component of a MV beam to study detector response separately in each case for a better understanding of the role of different effects influencing the response in nonstandard fields. METHODS Detector response in three different experimental setups was investigated for a variety of different types (diamond, shielded and unshielded diodes, ionization chamber and film): (a). Detectors positioned in water under a thin steel pole blocking the central part of the beam, yielding only the response to the scatter part of the beam. (b). Detectors positioned in air under a PMMA cap to approximate the contribution of the primary beam without scatter. (c). Detectors positioned in water in the standard open field configuration to obtain a superposition of both. RESULTS Detector differences became more clearly observable when the primary beam was blocked and detector behavior heavily depended on the construction type. It was possible to calculate the response in the open fields from the values measured in the blocked configuration with 1% accuracy for all studied field sizes between 0.8 and 10 cm and for all detectors. CONCLUSIONS The limitations of clinically used detectors in nonstandard situations were illustrated in the extreme situation of just scattered radiation reaching the detector. By experimentally separating scatter from the primary beam, the roles of different effects on the detector response were observed.
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Affiliation(s)
- Sonja Wegener
- Department of Radiation Oncology, University of Würzburg, 97080, Würzburg, Germany
| | - Otto A Sauer
- Department of Radiation Oncology, University of Würzburg, 97080, Würzburg, Germany
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Ikeda H, Souda H, Puspitasari A, Held KD, Hidema J, Nikawa T, Yoshida Y, Kanai T, Takahashi A. Development and performance evaluation of a three-dimensional clinostat synchronized heavy-ion irradiation system. LIFE SCIENCES IN SPACE RESEARCH 2017; 12:51-60. [PMID: 28212708 DOI: 10.1016/j.lssr.2017.01.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 01/21/2017] [Indexed: 06/06/2023]
Abstract
Outer space is an environment characterized by microgravity and space radiation, including high-energy charged particles. Astronauts are constantly exposed to both microgravity and radiation during long-term stays in space. However, many aspects of the biological effects of combined microgravity and space radiation remain unclear. We developed a new three-dimensional (3D) clinostat synchronized heavy-ion irradiation system for use in ground-based studies of the combined exposures. Our new system uses a particle accelerator and a respiratory gating system from heavy-ion radiotherapy to irradiate samples being rotated in the 3D clinostat with carbon-ion beams only when the samples are in the horizontal position. A Peltier module and special sample holder were loaded on a static stage (standing condition) and the 3D clinostat (rotation condition) to maintain a suitable temperature under atmospheric conditions. The performance of the new device was investigated with normal human fibroblasts 1BR-hTERT in a disposable closed cell culture chamber. Live imaging revealed that cellular adhesion and growth were almost the same for the standing control sample and rotation sample over 48h. Dose flatness and symmetry were judged according to the relative density of Gafchromic films along the X-axis and Y-axis of the positions of the irradiated sample to confirm irradiation accuracy. Doses calculated using the carbon-ion calibration curve were almost the same for standing and rotation conditions, with the difference being less than 5% at 1Gy carbon-ion irradiation. Our new device can accurately synchronize carbon-ion irradiation and simulated microgravity while maintaining the temperature under atmospheric conditions at ground level.
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Affiliation(s)
- Hiroko Ikeda
- Gunma University Heavy Ion Medical Center, Maebashi, Gunma 371-8511, Japan
| | - Hikaru Souda
- Gunma University Heavy Ion Medical Center, Maebashi, Gunma 371-8511, Japan
| | | | - Kathryn D Held
- Gunma University Initiative for Advanced Research, Maebashi, Gunma 371-8511, Japan; Department of Radiation Oncology, Massachusetts General Hospital/Harvard Medical School, Boston, MA 02114, USA
| | - Jun Hidema
- Department of Environmental Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Takeshi Nikawa
- Department of Nutritional Physiology, Institute of Medical Nutrition, Tokushima University Graduate School, Tokushima, Tokushima 770-8503, Japan
| | - Yukari Yoshida
- Gunma University Heavy Ion Medical Center, Maebashi, Gunma 371-8511, Japan
| | - Tatsuaki Kanai
- Gunma University Heavy Ion Medical Center, Maebashi, Gunma 371-8511, Japan
| | - Akihisa Takahashi
- Gunma University Heavy Ion Medical Center, Maebashi, Gunma 371-8511, Japan.
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Lewis DF, Chan MF. Technical Note: On GAFChromic EBT-XD film and the lateral response artifact. Med Phys 2016; 43:643-9. [PMID: 26843228 DOI: 10.1118/1.4939226] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The new radiochromic film, GAFChromic EBT-XD, contains the same active material, lithium-10,12-pentacosadiynoate, as GAFChromic EBT3, but the crystalline form is different. This work investigates the effect of this change on the well-known lateral response artifact when EBT-XD film is digitized on a flatbed scanner. METHODS The dose response of a single production lot of EBT-XD was characterized by scanning an unexposed film plus a set of films exposed to doses between 2.5 and 50 Gy using 6 MV photons. To characterize the lateral response artifact, the authors used the unexposed film plus a subset of samples exposed to doses between 20 and 50 Gy. Digital images of these films were acquired at seven discrete lateral locations perpendicular to the scan direction on three Epson 10000XL scanners. Using measurements at the discrete lateral positions, the scanner responses were determined as a function of the lateral position of the film. From the data for each scanner, a set of coefficients were derived whereby measured response values could be corrected to remove the effects of the lateral response artifact. The EBT-XD data were analyzed as in their previous work and compared to results reported for EBT3 in that paper. RESULTS For films scanned in the same orientation and having equal responses, the authors found that the lateral response artifact for EBT-XD and EBT3 films was remarkably similar. For both films, the artifact increases with increased net response. However, as EBT-XD is less sensitive than EBT3, a greater exposure dose is required to reach the same net response. On this basis, the lower sensitivity of EBT-XD relative to EBT3 results in less net response change for equal exposure and a reduction in the impact of the lateral response artifact. CONCLUSIONS The shape of the crystalline active component in EBT-XD and EBT3 does not affect the fundamental existence of the lateral response artifact when the films are digitized on flatbed scanners. Owing its lower sensitivity, EBT-XD film requires higher dose to reach the same response as EBT3, resulting in lesser impact of the lateral response artifact. For doses >10 Gy, the slopes of the EBT-XD red and green channel dose response curves are greater than the corresponding ones for EBT3. For these two reasons, the authors prefer EBT-XD for doses exceeding about 10 Gy.
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Affiliation(s)
- David F Lewis
- RC Film Consulting LLC, 54 Benedict Road, Monroe, Connecticut 06468
| | - Maria F Chan
- Memorial Sloan-Kettering Cancer Center, 136 Mountain View Boulevard, Basking Ridge, New Jersey 07920
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Schoenfeld AA, Wieker S, Harder D, Poppe B. The origin of the flatbed scanner artifacts in radiochromic film dosimetry—key experiments and theoretical descriptions. Phys Med Biol 2016; 61:7704-7724. [DOI: 10.1088/0031-9155/61/21/7704] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Grid patterns, spatial inter-scan variations and scanning reading repeatability in radiochromic film dosimetry. Phys Med 2016; 32:1072-81. [DOI: 10.1016/j.ejmp.2016.08.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 07/21/2016] [Accepted: 08/03/2016] [Indexed: 11/23/2022] Open
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Pérez Azorin JF, Garcia LIR, Ozcoidi DM, Almansa JF. Polarized dosimetry method for Gafchromic EBT3. Phys Med 2016; 32:972-80. [DOI: 10.1016/j.ejmp.2016.06.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 06/20/2016] [Accepted: 06/22/2016] [Indexed: 10/21/2022] Open
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Schoenfeld AA, Wieker S, Harder D, Poppe B. Changes of the optical characteristics of radiochromic films in the transition from EBT3 to EBT-XD films. Phys Med Biol 2016; 61:5426-5442. [DOI: 10.1088/0031-9155/61/14/5426] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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40
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Tamponi M, Bona R, Poggiu A, Marini P. A new form of the calibration curve in radiochromic dosimetry. Properties and results. Med Phys 2016; 43:4435. [DOI: 10.1118/1.4954208] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Evaluation of the incident directional dependence of radiochromic film by use of Monte Carlo simulation and measurement. Radiol Phys Technol 2016; 9:227-32. [PMID: 27010193 DOI: 10.1007/s12194-016-0353-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 03/07/2016] [Accepted: 03/11/2016] [Indexed: 10/22/2022]
Abstract
In high-precision radiotherapy, absolute and relative doses are evaluated for patient-specific intensity-modulated radiation therapy (IMRT) quality assurance (QA). In our institution, we use GAFCHROMIC EBT3 (EBT3) for relative dose evaluation in IMRT QA. We usually use two directional film configurations, which are in the axial and sagittal planes. The QA in our institution shows some differences between the gamma pass rates in the axial and sagittal directions. The purpose of this study was to evaluate the incident directional dependence of EBT3 by using the percent depth dose (PDD) and the off-center ratio (OCR) between EBT3 films positioned perpendicular to the beam axis and along the beam axis. Furthermore, we compared the PDD in EBT3 films positioned perpendicular to the beam axis and the PDD by using an ionization chamber. In addition, PDDs in water phantoms with and without EBT3 films were calculated by Monte Carlo simulation. The results showed that the PDD in EBT3 films positioned perpendicular to the beam axis increased with the depth from the phantom surface. Monte Carlo simulation showed the same trend as did the film measurements. The OCR results were slightly different at dose levels below 20 %. The OCR in EBT3 films positioned along the beam axis was higher than that perpendicular to the beam axis. Thus, we conclude that EBT3 film has incident directional dependence. In IMRT QA, the gamma analysis results may be affected by the incident directional dependence of EBT3 film.
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van Battum LJ, Huizenga H, Verdaasdonk RM, Heukelom S. How flatbed scanners upset accurate film dosimetry. Phys Med Biol 2015; 61:625-49. [PMID: 26689962 DOI: 10.1088/0031-9155/61/2/625] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Film is an excellent dosimeter for verification of dose distributions due to its high spatial resolution. Irradiated film can be digitized with low-cost, transmission, flatbed scanners. However, a disadvantage is their lateral scan effect (LSE): a scanner readout change over its lateral scan axis. Although anisotropic light scattering was presented as the origin of the LSE, this paper presents an alternative cause. Hereto, LSE for two flatbed scanners (Epson 1680 Expression Pro and Epson 10000XL), and Gafchromic film (EBT, EBT2, EBT3) was investigated, focused on three effects: cross talk, optical path length and polarization. Cross talk was examined using triangular sheets of various optical densities. The optical path length effect was studied using absorptive and reflective neutral density filters with well-defined optical characteristics (OD range 0.2-2.0). Linear polarizer sheets were used to investigate light polarization on the CCD signal in absence and presence of (un)irradiated Gafchromic film. Film dose values ranged between 0.2 to 9 Gy, i.e. an optical density range between 0.25 to 1.1. Measurements were performed in the scanner's transmission mode, with red-green-blue channels. LSE was found to depend on scanner construction and film type. Its magnitude depends on dose: for 9 Gy increasing up to 14% at maximum lateral position. Cross talk was only significant in high contrast regions, up to 2% for very small fields. The optical path length effect introduced by film on the scanner causes 3% for pixels in the extreme lateral position. Light polarization due to film and the scanner's optical mirror system is the main contributor, different in magnitude for the red, green and blue channel. We concluded that any Gafchromic EBT type film scanned with a flatbed scanner will face these optical effects. Accurate dosimetry requires correction of LSE, therefore, determination of the LSE per color channel and dose delivered to the film.
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Affiliation(s)
- L J van Battum
- Physics and Medical Technology, VU University Medical Center, Support Radiotherapy, PO Box 7057, 1007 MB Amsterdam, The Netherlands
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Palmer AL, Dimitriadis A, Nisbet A, Clark CH. Evaluation of Gafchromic EBT-XD film, with comparison to EBT3 film, and application in high dose radiotherapy verification. Phys Med Biol 2015; 60:8741-52. [DOI: 10.1088/0031-9155/60/22/8741] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Lewis D, Chan MF. Correcting lateral response artifacts from flatbed scanners for radiochromic film dosimetry. Med Phys 2015; 42:416-29. [PMID: 25563282 DOI: 10.1118/1.4903758] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE A known factor affecting the accuracy of radiochromic film dosimetry is the lateral response artifact (LRA) induced by nonuniform response of a flatbed scanner in the direction perpendicular to the scan direction. This work reports a practical solution to eliminate such artifacts for all forms of dose QA. METHODS EBT3 films from a single production lot (02181401) cut into rectangular 4 × 5 cm(2) pieces, with the long dimension parallel to the long dimension of the original 20.3 × 25.4 cm(2) sheets, were exposed at a depth of 5 cm on a Varian Trilogy at the center of a 20 × 20 cm(2) open field at seven doses between 50 and 1600 cGy using 6 MV photons. These films together with an unexposed film from the same production lot were lined one next to the other on an Epson 10000 XL or 11000 XL scanner in portrait orientation with their long dimension parallel to the scan direction. Scanned images were then obtained with the line of films positioned at seven discrete lateral locations perpendicular to the scan direction. The process was repeated in landscape orientation and on three other Epson scanners. Data were also collected for three additional production lots of EBT3 film (11051302, 03031401, and 03171403). From measurements at the various lateral positions, the scanner response was determined as a function of the lateral position of the scanned film. For a given color channel X, the response at any lateral position L is related to the response at the center, C, of the scanner by Response(C, D, X) = A(L,X) + B(L,X) ⋅ Response(L, D, X), where D is dose and the coefficients A(L,X) and B(L,X) are determined from the film measurements at the center of the scanner and six other discrete lateral positions. The values at intermediate lateral positions were obtained by linear interpolation. The coefficients were determined for the red, green, and blue color channels, preserving the ability to apply triple-channel dosimetry once corrections were applied to compensate for the lateral position response artifact. To validate this method, corrections were applied to several films that were exposed to 15 × 15 cm(2) open fields and large IMRT and VMAT fields and scanned at the extreme edges of the scan window in addition to the central location. Calibration and response data were used to generate dose maps and perform gamma analysis using single- or triple-channel dosimetry with FilmQAPro 2014 software. RESULTS The authors' study found that calibration curves at the different lateral positions could be correlated by a simple two-point rescaling using the response for unexposed film as well as the response of film exposed at high doses between 800 and 1600 cGy. The coefficients A(L,X) and BL,X for each color channel X were found to be independent of dose at each lateral location L. This made it possible to apply the relationship Response(C, D, X) = A(L,X) + B(L,X) ⋅ Response(L, D, X), to the raw film responses, permitting correction of the response values at any lateral position to an equivalent response, as if that part of the film was located at the center of the scanner. This correction method was validated for several films exposed to open as well as large IMRT and VMAT fields. CONCLUSIONS The work reported elaborates on the process using the correction procedures to eliminate the lateral response artifact and demonstrates improvements in the accuracy of radiochromic film dosimetry for the radiation therapy quality assurance applications.
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Affiliation(s)
- David Lewis
- RCF Consulting, LLC, 54 Benedict Road, Monroe, Connecticut 06468
| | - Maria F Chan
- Memorial Sloan-Kettering Cancer Center, 136 Mountain View Boulevard, Basking Ridge, New Jersey 07920
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Rakowski JT, Laha SS, Snyder MG, Buczek MG, Tucker MA, Liu F, Mao G, Hillman Y, Lawes G. Measurement of gold nanofilm dose enhancement using unlaminated radiochromic film. Med Phys 2015; 42:5937-44. [DOI: 10.1118/1.4931054] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Grams MP, Gustafson JM, Long KM, de los Santos LEF. Technical Note: Initial characterization of the new EBT-XD Gafchromic film. Med Phys 2015; 42:5782-6. [DOI: 10.1118/1.4930058] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Lewis D, Devic S. Correcting scan-to-scan response variability for a radiochromic film-based reference dosimetry system. Med Phys 2015; 42:5692-701. [DOI: 10.1118/1.4929563] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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