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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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2
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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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3
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Hall AV, Musa OM, Hood DK, Apperley DC, Yufit DS, Steed JW. Alkali Metal Salts of 10,12-Pentacosadiynoic Acid and Their Dosimetry Applications. CRYSTAL GROWTH & DESIGN 2021. [PMID: 34054354 DOI: 10.1021/acs.cgd.1c00300] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Wide-dose-range 2D radiochromic films for radiotherapy, such as GAFchromic EBT, are based on the lithium salt of 10,12-pentacosadiynoic acid (Li-PCDA) as the photosensitive component. We show that there are two solid forms of Li-PCDA-a monohydrated form A and an anhydrous form B. The form used in commercial GAFchromic films is form A due to its short needle-shaped crystals, which provide favorable coating properties. Form B provides an enhanced photoresponse compared to that of form A, but adopts a long needle crystal morphology, which is difficult to process. The two forms were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, CP-MAS 13C solid-state NMR spectroscopy, and thermogravimetric analysis. In sum, these data suggest a chelating bridging bidentate coordination mode for the lithium ions. The sodium salt of PCDA (Na-PCDA) is also reported, which is an ionic cocrystal with a formula of Na+PCDA-·3PCDA. The PCDA and PCDA- ligands display monodentate and bridging bidentate coordination to the sodium ion in contrast to the coordination sphere of the Li-PCDA forms. In contrast to its lithium analogues, Na-PCDA is photostable.
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Affiliation(s)
- Amy V Hall
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham DH1 3LE, U.K
| | - Osama M Musa
- Ashland LLC, 1005 Route 202/206, Bridgewater, New Jersey 08807, United States
| | - David K Hood
- Ashland LLC, 1005 Route 202/206, Bridgewater, New Jersey 08807, United States
| | - David C Apperley
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham DH1 3LE, U.K
| | - Dmitry S Yufit
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham DH1 3LE, U.K
| | - Jonathan W Steed
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham DH1 3LE, U.K
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4
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Hall AV, Musa OM, Hood DK, Apperley DC, Yufit DS, Steed JW. Alkali Metal Salts of 10,12-Pentacosadiynoic Acid and Their Dosimetry Applications. CRYSTAL GROWTH & DESIGN 2021; 21:2416-2422. [PMID: 34054354 PMCID: PMC8154271 DOI: 10.1021/acs.cgd.1c00031] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 03/17/2021] [Indexed: 05/22/2023]
Abstract
Wide-dose-range 2D radiochromic films for radiotherapy, such as GAFchromic EBT, are based on the lithium salt of 10,12-pentacosadiynoic acid (Li-PCDA) as the photosensitive component. We show that there are two solid forms of Li-PCDA-a monohydrated form A and an anhydrous form B. The form used in commercial GAFchromic films is form A due to its short needle-shaped crystals, which provide favorable coating properties. Form B provides an enhanced photoresponse compared to that of form A, but adopts a long needle crystal morphology, which is difficult to process. The two forms were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, CP-MAS 13C solid-state NMR spectroscopy, and thermogravimetric analysis. In sum, these data suggest a chelating bridging bidentate coordination mode for the lithium ions. The sodium salt of PCDA (Na-PCDA) is also reported, which is an ionic cocrystal with a formula of Na+PCDA-·3PCDA. The PCDA and PCDA- ligands display monodentate and bridging bidentate coordination to the sodium ion in contrast to the coordination sphere of the Li-PCDA forms. In contrast to its lithium analogues, Na-PCDA is photostable.
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Affiliation(s)
- Amy V. Hall
- Department
of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham DH1 3LE, U.K.
| | - Osama M. Musa
- Ashland
LLC, 1005 Route 202/206, Bridgewater, New Jersey 08807, United States
| | - David K. Hood
- Ashland
LLC, 1005 Route 202/206, Bridgewater, New Jersey 08807, United States
| | - David C. Apperley
- Department
of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham DH1 3LE, U.K.
| | - Dmitry S. Yufit
- Department
of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham DH1 3LE, U.K.
| | - Jonathan W. Steed
- Department
of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham DH1 3LE, U.K.
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5
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Akino Y, Shiomi H, Isohashi F, Suzuki O, Seo Y, Tamari K, Hirata T, Mizuno H, Ogawa K. Correction of lateral response artifacts from flatbed scanners for dual-channel radiochromic film dosimetry. JOURNAL OF RADIATION RESEARCH 2021; 62:319-328. [PMID: 33479768 PMCID: PMC7948896 DOI: 10.1093/jrr/rraa124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 10/14/2020] [Indexed: 06/12/2023]
Abstract
In this study, we evaluated the inter-unit variability of the lateral response artifact for multiple flatbed scanners, focusing on the dual-channel method, and investigated the correction method of the lateral non-uniformity. Four scanners with A3+ paper-size and five scanners with A4 paper-size were evaluated. To generate the dose-response curves, small pieces of the Gafchromic EBT3 and EBT-XD films were irradiated, and five of the pieces were repeatedly scanned by moving them on the scanner to evaluate the lateral non-uniformity. To calculate the dose distribution accounting for the lateral non-uniformity, linear functions of the correction factor, representing the difference between the pixel values at offset position and the scanner midline, were calculated for red and blue color channels at each lateral position. Large variations of the lateral non-uniformity among the scanners were observed, even for the same model of scanner. For high dose, red color showed pixel value profiles similar to symmetric curves, whereas the profiles for low dose were asymmetric. The peak positions changed with dose. With correction of the lateral non-uniformity, the dose profiles of the pyramidal dose distribution measured at various scanner positions and that calculated with a treatment planning system showed almost identical profile shapes at all high-, middle- and low-dose levels. The dual-channel method used in this study showed almost identical dose profiles measured with all A3+ and A4 paper-size scanners at any positions when the corrections were applied for each color channel.
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Affiliation(s)
- Yuichi Akino
- Corresponding author. Oncology Center, Osaka University Hospital, 2-2 (D10), Yamadaoka, Suita, Osaka, 565-0871, Japan. Tel: (+81) 6-6879-3482; Fax: (+81) 6-6879-3489;
| | - Hiroya Shiomi
- Osaka University Graduate School of Meidcine, Suita, Osaka 565-0871, Japan
| | - Fumiaki Isohashi
- Osaka University Graduate School of Meidcine, Suita, Osaka 565-0871, Japan
| | - Osamu Suzuki
- Osaka Heavy Ion Therapy Center, Osaka 540-0008, Japan
| | - Yuji Seo
- Osaka University Graduate School of Meidcine, Suita, Osaka 565-0871, Japan
| | - Keisuke Tamari
- Osaka University Graduate School of Meidcine, Suita, Osaka 565-0871, Japan
| | - Takero Hirata
- Osaka University Graduate School of Meidcine, Suita, Osaka 565-0871, Japan
| | | | - Kazuhiko Ogawa
- Osaka University Graduate School of Meidcine, Suita, Osaka 565-0871, Japan
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6
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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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7
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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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8
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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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9
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León‐Marroquín EY, Mulrow D, Darafsheh A, Khan R. Response characterization of EBT‐XD radiochromic films in megavoltage photon and electron beams. Med Phys 2019; 46:4246-4256. [DOI: 10.1002/mp.13708] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 06/12/2019] [Accepted: 07/03/2019] [Indexed: 11/09/2022] Open
Affiliation(s)
- E. Yazmin León‐Marroquín
- Department of Radiation Oncology Washington University School of Medicine St. Louis MO 63110 USA
| | - Daniel Mulrow
- Department of Radiation Oncology Washington University School of Medicine St. Louis MO 63110 USA
- Department of Chemistry Washington University in St. Louis St. Louis MO 63110 USA
| | - Arash Darafsheh
- Department of Radiation Oncology Washington University School of Medicine St. Louis MO 63110 USA
| | - Rao Khan
- Department of Radiation Oncology Washington University School of Medicine St. Louis MO 63110 USA
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10
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Vallières S, Bienvenue C, Puyuelo-Valdes P, Salvadori M, d'Humières E, Schiettekatte F, Antici P. Low-energy proton calibration and energy-dependence linearization of EBT-XD radiochromic films. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:083301. [PMID: 31472601 DOI: 10.1063/1.5109644] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 07/11/2019] [Indexed: 06/10/2023]
Abstract
In this work, we calibrate the newly developed EBT-XD radiochromic films (RCFs) manufactured by Gafchromictm using protons in the energy range of 4-10 MeV. Irradiation was performed on the 2 × 6 MV tandem linear accelerator located at the Université de Montréal. The RCFs were digitized using an Epson Perfection V700 flatbed scanner using both the red-green-blue and grayscale channels. The proton fluences were measured with Faraday cups calibrated in absolute terms. The linear energy transfer function within the active layer of the films was calculated using the mass stopping power tables coming from the PSTAR database from the National Institute of Standards and Technology (NIST) to allow retrieval of the deposited dose. We find that the calibration curves for 7 and 10 MeV protons are nearly equivalent. The 4 MeV calibration curves exhibit a quenching effect due to the Bragg peak that falls close to the active layer. A linearization of this energy dependence was developed using a semiempirical parametric model to allow the generation of calibration curves for any incident proton energy within the present range. Excellent correspondence (<5% dose difference for the same netOD) of the 10 MeV calibration curves was noted when compared to existing high-energy proton (148.2 MeV) calibration curves reported in the literature. Our calibration extends the range of operation of EBT-XD films to low-energy proton beam dosimetry.
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Affiliation(s)
- S Vallières
- INRS-EMT, 1650 Blvd. Lionel-Boulet, Varennes, Quebec J3X 1P7, Canada
| | - C Bienvenue
- INRS-EMT, 1650 Blvd. Lionel-Boulet, Varennes, Quebec J3X 1P7, Canada
| | - P Puyuelo-Valdes
- INRS-EMT, 1650 Blvd. Lionel-Boulet, Varennes, Quebec J3X 1P7, Canada
| | - M Salvadori
- INRS-EMT, 1650 Blvd. Lionel-Boulet, Varennes, Quebec J3X 1P7, Canada
| | - E d'Humières
- CELIA, University of Bordeaux, 351 Cours de la Libération, Talence 33400, France
| | - F Schiettekatte
- University of Montreal, 2900 Boulevard Edouard-Montpetit, Montréal, Quebec H3T 1J4, Canada
| | - P Antici
- INRS-EMT, 1650 Blvd. Lionel-Boulet, Varennes, Quebec J3X 1P7, Canada
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11
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Shi C, Chen CC, Mah D, Chan MF. Monte Carlo calculation of the mass stopping power of EBT3 and EBT-XD films for protons for energy ranges of 50-400 MeV. PRECISION RADIATION ONCOLOGY 2019; 2:106-113. [PMID: 31131334 PMCID: PMC6532660 DOI: 10.1002/pro6.55] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Objective The goal of the present study was to calculate the continuous slowing down approximation (CDSA) ranges and derive mass stopping power for EBT3 and EBT-XD films for therapeutic protons energy ranges of 50-400 MeV. Methods The MCNPX and TRansport of Ions in Matter (TRIM) Monte Carlo codes were used in this study. Utilizing the published International Commission on Radiation Units and Measurement 49 data for the water mass stopping power and CSDA ranges, the mass stopping powers of EBT3 and EBT-XD films were derived using the approximation proposed by Newhauser and Zhang in 2009. Results The calculated CSDA ranges by MCNPX and TRIM in water were first benchmarked to International Commission on Radiation Units and Measurement 49 published data for water, and found to be within 1% with a 1.4-mm maximum difference. The calculated CSDA values in EBT3 film, compared with the measured CSDA ranges in the EBT3 film, were within 2% of the calculated values with a 3-mm maximum difference. The MCNPX and TRIM results for CSDA ranges agreed with each other to within 2.7% for EBT3 film and 4.4% for EBT-XD film. The overall uncertainties of the MCNPX and TRIM-derived CSDA ranges were 3% and 1.3%, respectively. Conclusion The mass stopping powers for Gafchromic EBT3 and EBT-XD films were derived.
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Affiliation(s)
- Chengyu Shi
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, Basking Ridge, New Jersey, USA
| | - Chin-Cheng Chen
- Department of Radiation Physics, ProCure Proton Center, Somerset, New Jersey, USA
| | - Dennis Mah
- Department of Radiation Physics, ProCure Proton Center, Somerset, New Jersey, USA
| | - Maria F Chan
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, Basking Ridge, New Jersey, USA
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12
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Volotskova O, Fang X, Keidar M, Chandarana H, Das IJ. Microstructure changes in radiochromic films due to magnetic field and radiation. Med Phys 2018; 46:293-301. [PMID: 30341911 DOI: 10.1002/mp.13248] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 10/01/2018] [Accepted: 10/05/2018] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To correlate the dose response and changes in microscopic structures of the radiochromic films exposed to the clinical magnetic field in the range 1.5-3 T with standard and flattening filter-free (FFF) photon beams. METHODS The radiochromic film was cut into 5 × 5 cm2 sheets/samples from one batch. These samples were exposed to a 1.5-T and/or 3-T B-fields from an MRI scanner using an abdominal sequence for 7 min before and after irradiation with 6 MV and/or 6 MV FFF beams. Films were placed in a reference condition at 5 cm depth in a solid water phantom and exposed up to 20 Gy. The sample orientation was maintained the same during exposure, readout, and scanning electron microscopic (SEM) analysis. The samples were scanned with an Epson Expression 11000XL in a 48-bit RGB color mode at 300 dpi with red channel. Scanned images were processed in Image J and red channel mean intensity values were recorded. The samples were then coated with 6 nm gold and imaged by SEM Teneo (5 kV, 13 pA) under 2000, 2500, and 3000 magnifications for texture analysis. RESULTS The changes in the microstructure of the films in magnetic fields (1.5- and 3.0-T) were dose dependent. The orientation and granular size of samples at higher doses were altered compared to the controls. Needle-shaped structures of the active layer were longer and aligned for samples exposed to higher doses and magnetic field. However, no significant changes in optical density due to the presence of a magnetic field pre/postirradiation up to 20 Gy were observed. CONCLUSION Fine structures of the film represent the polymerization characteristics that are affected by the radiation dose in the magnetic field. Upon exposure to radiation, diacetylene monomers undergo polymerization that forms longer chains with a temporal response. Even though this study did not notice any significant changes in optical density due to the presence of magnetic field, this should be studied in simultaneous application of the magnetic field during treatment in a dedicated MR-linac unit.
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Affiliation(s)
- Olga Volotskova
- Department of Radiation Oncology, NYU Langone Medical Center & Laura and Isaac Perlmutter Cancer Center, New York, NY, 10016, USA
| | - Xuiqi Fang
- Department of Mechanical and Aerospace Engineering, George Washington University, Washington, DC, 20052, USA
| | - Michael Keidar
- Department of Mechanical and Aerospace Engineering, George Washington University, Washington, DC, 20052, USA
| | - Hersh Chandarana
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, NYU Langone Medical Center, New York, NY, 10016, USA
| | - Indra J Das
- Department of Radiation Oncology, NYU Langone Medical Center & Laura and Isaac Perlmutter Cancer Center, New York, NY, 10016, USA
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13
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Feng Y, Tiedje HF, Gagnon K, Fedosejevs R. Spectral calibration of EBT3 and HD-V2 radiochromic film response at high dose using 20 MeV proton beams. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:043511. [PMID: 29716332 DOI: 10.1063/1.4996022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Radiochromic film is used extensively in many medical, industrial, and scientific applications. In particular, the film is used in analysis of proton generation and in high intensity laser-plasma experiments where very high dose levels can be obtained. The present study reports calibration of the dose response of Gafchromic EBT3 and HD-V2 radiochromic films up to high exposure densities. A 2D scanning confocal densitometer system is employed to carry out accurate optical density measurements up to optical density 5 on the exposed films at the peak spectral absorption wavelengths. Various wavelengths from 400 to 740 nm are also scanned to extend the practical dose range of such films by measuring the response at wavelengths removed from the peak response wavelengths. Calibration curves for the optical density versus exposure dose are determined and can be used for quantitative evaluation of measured doses based on the measured optical densities. It was found that blue and UV wavelengths allowed the largest dynamic range though at some trade-off with overall accuracy.
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Affiliation(s)
- Yiwei Feng
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton T6G2V4, Alberta, Canada
| | - Henry F Tiedje
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton T6G2V4, Alberta, Canada
| | - Katherine Gagnon
- Medical Isotope and Cyclotron Facility, University of Alberta, Edmonton T6G2V4, Alberta, Canada
| | - Robert Fedosejevs
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton T6G2V4, Alberta, Canada
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Khachonkham S, Dreindl R, Heilemann G, Lechner W, Fuchs H, Palmans H, Georg D, Kuess P. Characteristic of EBT-XD and EBT3 radiochromic film dosimetry for photon and proton beams. ACTA ACUST UNITED AC 2018; 63:065007. [DOI: 10.1088/1361-6560/aab1ee] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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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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