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Mansour IR, Thomson RM. Haralick texture analysis for microdosimetry: characterization of Monte Carlo generated 3D specific energy distributions. Phys Med Biol 2023; 68:185003. [PMID: 37591252 DOI: 10.1088/1361-6560/acf183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 08/17/2023] [Indexed: 08/19/2023]
Abstract
Objective.Explore the application of Haralick textural analysis to 3D distributions of specific energy (energy imparted per unit mass) scored in cell-scale targets considering varying mean specific energy (absorbed dose), target volume, and incident spectrum.Approach.Monte Carlo simulations are used to generate specific energy distributions in cell-scale water voxels ((1μm)3-(15μm)3) irradiated by photon sources (mean energies: 0.02-2 MeV) to varying mean specific energies (10-400 mGy). Five Haralick features (homogeneity, contrast, entropy, correlation, local homogeneity) are calculated using an implementation of Haralick analysis designed to reduce sensitivity to grey level quantization and are interpreted using fundamental radiation physics.Main results.Haralick measures quantify differences in 3D specific energy distributions observed with varying voxel volume, absorbed dose magnitude, and source spectrum. For example, specific energy distributions in small (1-3μm) voxels with low magnitudes of absorbed dose (10 mGy) have relatively high measures of homogeneity and local homogeneity and relatively low measures of contrast and entropy (all relative to measures for larger voxels), reflecting the many voxels with zero specific energy in an otherwise sporadic distribution. With increasing target size, energy is shared across more target voxels, and trends in Haralick measures, such as decreasing homogeneity and increasing contrast and entropy, reflect characteristics of each 3D specific energy distribution. Specific energy distributions for sources of differing mean energy are characterized by Haralick measures, e.g. contrast generally decreases with increasing source energy, correlation and homogeneity are often (not always) higher for higher energy sources.Significance.Haralick texture analysis successfully quantifies spatial trends in 3D specific energy distributions characteristic of radiation source, target size, and absorbed dose magnitude, thus offering new avenues to quantify microdosimetric data beyond first order histogram features. Promising future directions include investigations of multiscale tissue models, targeted radiation therapy techniques, and biological response to radiation.
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Affiliation(s)
- Iymad R Mansour
- Carleton Laboratory for Radiotherapy Physics, Physics Department, Carleton University, 1125 Colonel By Dr, Ottawa, K1S 5B6, Ontario, Canada
| | - Rowan M Thomson
- Carleton Laboratory for Radiotherapy Physics, Physics Department, Carleton University, 1125 Colonel By Dr, Ottawa, K1S 5B6, Ontario, Canada
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Mansour IR, Thomson RM. Haralick texture feature analysis for characterization of specific energy and absorbed dose distributions across cellular to patient length scales. Phys Med Biol 2023; 68. [PMID: 36731130 DOI: 10.1088/1361-6560/acb885] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 02/02/2023] [Indexed: 02/04/2023]
Abstract
Objective.To investigate an approach for quantitative characterization of the spatial distribution of dosimetric data by introducing Haralick texture feature analysis in this context.Approach.Monte Carlo simulations are used to generate 3D arrays of dosimetric data for 2 scenarios: (1) cell-scale microdosimetry: specific energy (energy imparted per unit mass) in cell-scale targets irradiated by photon spectra (125I,192Ir, 6 MV); (2) tumour-scale dosimetry: absorbed dose in voxels for idealized models of125I permanent implant prostate brachytherapy, considering 'TG186' (realistic tissues including 0% to 5% intraprostatic calcifications; interseed attenuation) and 'TG43' (water model, no interseed attenuation) conditions. Five prominent Haralick features (homogeneity, contrast, correlation, local homogeneity, entropy) are computed and trends are interpreted using fundamental radiation physics.Main results.In the cell-scale scenario, the Haralick measures quantify differences in 3D specific energy distributions due to source spectra. For example, contrast and entropy are highest for125I reflecting the large variations in specific energy in adjacent voxels (photoelectric interactions; relatively short range of electrons), while 6 MV has the highest homogeneity with smaller variations in specific energy between voxels (Compton scattering dominates; longer range of electrons). For the tumour-scale scenario, the Haralick measures quantify differences due to TG186/TG43 simulation conditions and the presence of calcifications. For example, as calcifications increase from 0% to 5%, contrast increases while correlation decreases, reflecting the large differences in absorbed dose in adjacent voxels (higher absorbed dose in voxels with calcification due to photoelectric interactions).Significance.Haralick texture analysis provides a quantitative method for the characterization of 3D dosimetric distributions across cellular to tumour length scales, with promising future applications including analyses of multiscale tissue models, patient-specific data, and comparison of treatment approaches.
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Affiliation(s)
- Iymad R Mansour
- Carleton Laboratory for Radiotherapy Physics, Physics Department, Carleton University, 1125 Colonel By Dr, Ottawa, K1S 5B6, Ontario, Canada
| | - Rowan M Thomson
- Carleton Laboratory for Radiotherapy Physics, Physics Department, Carleton University, 1125 Colonel By Dr, Ottawa, K1S 5B6, Ontario, Canada
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Abu Mhanna HY, Omar AF, Radzi YM, Akhdar HF, Al Ewaidat H. Expired EBT3 Films’ Sensitivity for the Measurement of X-ray and UV Radiation: An Optical Analysis. MATERIALS 2022; 15:ma15082903. [PMID: 35454597 PMCID: PMC9027090 DOI: 10.3390/ma15082903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/15/2022] [Accepted: 04/13/2022] [Indexed: 11/25/2022]
Abstract
The aim of this study is to compare the optical responses of external beam therapy 3 (EBT3) films exposed to X-rays and solar ultraviolet rays (SUV-rays), as a dose control technique in the clinical sector for various radiation types, energies, and absorbed doses up to 4 Gy. In this study, EBT3 films with three different expiry dates were prepared and cut into pieces of size 2 by 2 cm2. The first group was exposed to 90 kVp X-rays, while the second group was exposed to the SUV-rays at noon. The analysis was performed using a visible Jaz spectrometer and an EPSON Perfection V370 Photo scanner to obtain the absorbance, the net reflective optical density (ROD) and the red-green-blue (RGB) values of the samples. The results have shown that spectroscopic measurements of the exposed expired EBT3 films with these radiation sources are able to produce primary peaks and secondary peaks at λ = 641.74 nm and λ = 585.98 nm for X-rays, and at λ = 637.93 nm and λ = 584.45 nm for SUV-rays, respectively. According to these findings, compared to 2021 films that expired shortly before the trial start date; 2018 films responded better to the absorbed dose than 2016 films when exposed to both X-ray and SUV-rays. In terms of energy dependence, the expired EBT3 2018 had the largest net ROD value. Using L*a*b* indices extracted from the RGB data, and despite that EBT3 films have expiry dates according to the manufacturer; all the films exhibited a substantial colour change, indicating that these films are still usable for clinical and research purposes.
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Affiliation(s)
- Hamad Yahia Abu Mhanna
- School of Physics, Universiti Sains Malaysia, Penang 11800, Malaysia;
- Correspondence: (H.Y.A.M.); (A.F.O.); (H.F.A.)
| | - Ahmad Fairuz Omar
- School of Physics, Universiti Sains Malaysia, Penang 11800, Malaysia;
- Correspondence: (H.Y.A.M.); (A.F.O.); (H.F.A.)
| | - Yasmin Md Radzi
- School of Physics, Universiti Sains Malaysia, Penang 11800, Malaysia;
| | - Hanan Fawaz Akhdar
- Physics Department, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 13318, Saudi Arabia
- Correspondence: (H.Y.A.M.); (A.F.O.); (H.F.A.)
| | - Haytham Al Ewaidat
- Department of Allied Medical Sciences-Radiologic Technology, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid 22110, Jordan;
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Optical Response of Expired EBT3 Film for Absorbed Dose Measurement in X-ray and Electron Beam Range. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12083974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The purpose of this study was to investigate the optical response of an expired External Beam Therapy (EBT3) film, which expired in 2018, using X-rays and electron beam doses. The film’s optical responses were evaluated for its usability in measuring different radiation sources, energy, and absorbed doses ranging up to 5 Gy. Pieces of the expired EBT3 film were irradiated with 90 kVp, 6 MV X-ray photons, and 6 MeV electron beam. The analysis was performed using the Jaz visible spectrometer and EPSON Perfection V370 Photo scanner to obtain the absorbance and the net relative optical density (ROD) of the film samples respectively. The results showed that spectroscopic measurements of the exposed expired EBT3 films under these radiation sources were able to produce primary secondary peaks at λ = 633.52 nm and λ = 582.3 nm respectively. The best wavelength subsets that presented the best MLR regression fitting for all experiments were 541.48 nm, 561.11 nm, and 600.28 nm. While, for the 6 MV photon and the 6 MeV electron beam they were 600.28 nm, 650.79 nm and 654.10 nm. In case of the irradiation with the 6 MV photon and the 6 MeV electron beam, expired EBT3 film showed no significant differences, which made it suitable for dosimetry in various sources of radiation. The individual calibration of radiation dose produces very high measurement accuracy with coefficient of determination, R2 above 0.99 and root mean square of error, RMSE of 0.038 Gy, 0.113 Gy, and 0.115 Gy for films irradiated with 90 kVp X-rays, 6 MV photon beam, and 6 MeV electron beam respectively. Hence, from the results, the expired EBT3 film used in this study showed promising usability of expired EBT3 films beyond their prescribed expiry dates.
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Kakade NR, Das A, Kumar R, Sharma SD, Chadha R, Maiti N, Kapoor S. Application of unlaminated EBT3 film dosimeter for quantification of dose enhancement using silver nanoparticle-embedded alginate film. Biomed Phys Eng Express 2022; 8. [PMID: 35325874 DOI: 10.1088/2057-1976/ac60c5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 03/24/2022] [Indexed: 11/11/2022]
Abstract
Purpose.The paper describes the application of unlaminated Gafchromic EBT3 film dosimeter for quantification of dose enhancement using locally synthesized silver nanoparticle-embedded alginate film (AgNPs-Alg film) for nanoparticles-aided radiotherapy.Materials and Methods.AgNPs-Alg film was synthesized and characterized using standard techniques. The unlaminated Gafchromic EBT3 film was specially customized for dosimetric measurement. The dose enhancements due to AgNPs-Alg film was experimentally determined for ISO wide spectrum x-rays series (average energy ranging from 57-137 keV) and 6 and 10 MV x-rays using laminated and unlaminated Gafchromic EBT3 film. The radiation dose of 1 Gy was delivered to a combination of AgNPs-Alg films and EBT3 film.Results.Ultraviolet-Visible spectroscopy of silver nanoparticles shows a surface plasmon resonance peak at 400 nm. The average particle size of 13 ± 2 nm was measured using Atomic Force Microscopy. For unlaminated film, the dose enhancements of 29%, 23%, 14% and 2% was observed for ISO wide spectrum x-rays having average energy of 57, 79, 104 and 137 keV, respectively. The dose enhancement was negligible for 6 and 10 MV x-rays. In the case of laminated film, no significant dose enhancement was measured for all the x-ray energies.Conclusion.The unlaminated Gafchromic EBT3 film can be a suitable choice for the measurement of dose enhancement. Further, silver nanoparticles can be used during nanoparticle-aided radiotherapy when irradiated at low x-ray energy.
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Affiliation(s)
- Nitin R Kakade
- Radiological Physics & Advisory Division, Bhabha Atomic Research Centre, Mumbai-400094, India.,Homi Bhabha National Institute, Anushaktinagar, Mumbai-400094, India
| | - Abhishek Das
- Homi Bhabha National Institute, Anushaktinagar, Mumbai-400094, India.,Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai-400085, India
| | - Rajesh Kumar
- Radiological Physics & Advisory Division, Bhabha Atomic Research Centre, Mumbai-400094, India.,Homi Bhabha National Institute, Anushaktinagar, Mumbai-400094, India
| | - S D Sharma
- Radiological Physics & Advisory Division, Bhabha Atomic Research Centre, Mumbai-400094, India.,Homi Bhabha National Institute, Anushaktinagar, Mumbai-400094, India
| | - Ridhima Chadha
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai-400085, India
| | - Nandita Maiti
- Homi Bhabha National Institute, Anushaktinagar, Mumbai-400094, India.,Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai-400085, India
| | - Sudhir Kapoor
- Homi Bhabha National Institute, Anushaktinagar, Mumbai-400094, India.,Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai-400085, India
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Effects of X-ray irradiation on the structural and optical properties of microcrystalline Alq3 powder and its potential dosimetry application. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2021.109656] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Mcnairn C, Mansour I, Muir B, Thomson RM, Murugkar S. High spatial resolution dosimetry with uncertainty analysis using Raman micro-spectroscopy readout of radiochromic films. Med Phys 2021; 48:4610-4620. [PMID: 34042192 DOI: 10.1002/mp.15000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 05/06/2021] [Accepted: 05/10/2021] [Indexed: 11/11/2022] Open
Abstract
PURPOSE The purpose of this work is to develop a new approach for high spatial resolution dosimetry based on Raman micro-spectroscopy scanning of radiochromic film (RCF). The goal is to generate dose calibration curves over an extended dose range from 0 to 50 Gy and with improved sensitivity to low (<2 Gy) doses, in addition to evaluating the uncertainties in dose estimation associated with the calibration curves. METHODS Samples of RCF (EBT3) were irradiated at a broad dose range of 0.03-50 Gy using an Elekta Synergy clinical linear accelerator. Raman spectra were acquired with a custom-built Raman micro-spectroscopy setup involving a 500 mW, multimode 785 nm laser focused to a lateral spot diameter of 30 µm on the RCF. The depth of focus of 34 µm enabled the concurrent collection of Raman spectra from the RCF active layer and the polyester laminate. The preprocessed Raman spectra were normalized to the intensity of the 1614 cm-1 Raman peak from the polyester laminate that was unaltered by radiation. The mean intensities and the corresponding standard deviation of the active layer Raman peaks at 696, 1445, and 2060 cm-1 were determined for the 150 × 100 µm2 scan area per dose value. This was used to generate three calibration curves that enabled the conversion of the measured Raman intensity to dose values. The experimental, fitting, and total dose uncertainty was determined across the entire dose range for the dosimetry system of Raman micro-spectroscopy and RCF. RESULTS In contrast to previous work that investigated the Raman response of RCFs using different methods, high resolution in the dose response of the RCF, even down to 0.03 Gy, was obtained in this study. The dynamic range of the calibration curves based on all three Raman peaks in the RCF extended up to 50 Gy with no saturation. At a spatial resolution of 30 × 30 µm2 , the total uncertainty in estimating dose in the 0.5-50 Gy dose range was [6-9]% for all three Raman calibration curves. This consisted of the experimental uncertainty of [5-8]%, and the fitting uncertainty of [2.5-4.5]%. The main contribution to the experimental uncertainty was determined to be from the scan area inhomogeneity which can be readily reduced in future experiments. The fitting uncertainty could be reduced by performing Raman measurements on RCF samples at further intermediate dose values in the high and low dose range. CONCLUSIONS The high spatial resolution experimental dosimetry technique based on Raman micro-spectroscopy and RCF presented here, could become potentially useful for applications in microdosimetry to produce meaningful dose estimates in cellular targets, as well as for applications based on small field dosimetry that involve high dose gradients.
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Affiliation(s)
- Connor Mcnairn
- Department of Physics, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, K1S 5B6, Canada
| | - Iymad Mansour
- Department of Physics, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, K1S 5B6, Canada
| | - Bryan Muir
- Metrology Research Centre, National Research Council of Canada, 1125 Colonel By Drive, Ottawa, Ontario, K1A 0R6, Canada
| | - Rowan M Thomson
- Department of Physics, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, K1S 5B6, Canada
| | - Sangeeta Murugkar
- Department of Physics, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, K1S 5B6, Canada
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Hernández Millares R, Mirza JA, Lee J, Choi K, Eom M, Ye SJ. Radiosensitization by Au-nanofilm at micrometer level using confocal Raman spectroscopy. Med Phys 2021; 48:796-804. [PMID: 33128244 DOI: 10.1002/mp.14570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 10/05/2020] [Accepted: 10/05/2020] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To measure the radiosensitization by an Au-nanofilm (GNF) at a micrometer level on a radiochromic film (RCF) using confocal Raman spectroscopy (CRS). METHODS Unlaminated radiochromic films were irradiated by 200 kVp x-ray from 0.3 to 50 Gy to obtain a calibration curve. Raman spectra of these films were measured by positioning the postirradiated RCF perpendicular to the CRS monochromatic beam and reading a depth profile of the film along the lateral axis. The Raman peak corresponding to the C ≡ C peak was obtained from a region of interest of 100 × 5 µm2 . To investigate the radiosensitization by GNF, two sets of RCF, one attached to a 100-nm thick GNF and the other without GNF were irradiated at 0.5 Gy by 50 and 120 kVp X-rays. The spatial resolution of the CRS on the RCF was quantified by the modulation transfer function method (MTF). Thus, in the spatial resolution determined by MTF, the doses deposited on the films were evaluated. The dose enhancement factor (DEF) was obtained in the measurable micro-size by comparing doses deposited on the RCFs with and without GNF. To verify the experimental results, Monte Carlo simulations following the experimental set up were performed using Geant4. In addition, analytical calculations for the radiosensitization by GNF were carried out. RESULTS The confocal Raman spectroscopy on the RCF achieved a spatial resolution of ~6 μm. An experimental DEF within the first 6 μm depth from the surface of RCF was found to be 17.9 for 50 kVp and 14.7 for 120 kVp. The DEF for the same depth obtained by MC and analytical calculations was 13.53 and 9.75 for 50 kVp, and 10.63 and 6.67 for 120 kVp, respectively. CONCLUSIONS The experimental DEF as a function of the distance from GNF was consistent with data from previous studies and the MC simulations, supporting that CRS in conjunction with the RCF is a feasible micrometer-resolution dosimeter.
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Affiliation(s)
- Rodrigo Hernández Millares
- Program in Biomedical Radiation Sciences, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, 08826, Korea
| | - Jamal Ahmad Mirza
- Program in Biomedical Radiation Sciences, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, 08826, Korea.,Isotope Production Division, Pakistan Institute of Nuclear Science and Technology, Nilore, Islamabad, 44000, Pakistan
| | - Junyoung Lee
- Program in Biomedical Radiation Sciences, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, 08826, Korea
| | - Kwon Choi
- Program in Biomedical Radiation Sciences, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, 08826, Korea
| | - Mingi Eom
- Program in Biomedical Radiation Sciences, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, 08826, Korea
| | - Sung-Joon Ye
- Program in Biomedical Radiation Sciences, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, 08826, Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, 03080, Korea.,Advanced Institutes of Convergence Technology, Seoul National University, Suwon, 16229, Korea
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A Study of Structural Change During In Vitro Digestion of Heated Soy Protein Isolates. Foods 2019; 8:foods8120594. [PMID: 31756907 PMCID: PMC6963817 DOI: 10.3390/foods8120594] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 11/13/2019] [Accepted: 11/15/2019] [Indexed: 11/17/2022] Open
Abstract
Use of soy protein isolate (SPI) as the encapsulating material in emulsions is uncommon due to its low solubility and emulsification potential. The aim of this study was to improve these properties of SPI via heat treatment-induced modifications. We modified SPI under various heating conditions and demonstrated the relationship between structure and in vitro digestibility in simulated gastric fluid by means of Sodium Dodecyl Sulphide-Polyacrylamide Gel Electrophoresis (SDS-PAGE) and Raman spectroscopy. It was found that the degree of hydrolysis (DH) of SPI increased and then decreased upon increasing exposure to heat. Different subunits of conglycinin were digested and degraded by pepsin. Heat treatment improved digestion characteristics that would reduce e the unnecessary loss of protein, offering potential for the efficient delivery of nutrients in nanoemulsions. These results could have significant relevance for research groups that are interested in the biological interactions and activity of functional SPI.
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Measuring radioenhancement by gold nanofilms: Comparison with analytical calculations. Phys Med 2019; 68:1-9. [PMID: 31715285 DOI: 10.1016/j.ejmp.2019.10.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 10/18/2019] [Accepted: 10/29/2019] [Indexed: 11/22/2022] Open
Abstract
PURPOSE To measure radioenhancement by gold nanoparticles (GNPs) using gold nanofilms (GNFs). METHODS GNFs of 20-100 nm thicknesses were prepared. The GNF attached to radiochromic film (RCF) was irradiated using 50, 220 kVp, and 6 MV X-rays. The radiation doses to the active layer of RCF with and without GNF were measured using an optical flatbed scanner and Raman spectrometer to estimate the dose enhancement factor (DEF). For verification, analytical calculations of DEF within the thickness of active layer and the ranges of secondary electrons were carried out. RESULTS The DEFs for GNFs of 20 to 100 nm thicknesses measured by an optical scanner ranged from 2.1 to 6.1 at 50 kVp and 1.6 to 4.9 at 220 kVp. Similarly, the DEFs measured by Raman spectroscopy ranged from 2.6 to 4.6 at 50 kVp and 2.2 to 4.8 at 220 kVp. The calculated DEFs ranged from 1.5 to 3.6 at 50 kVp and from 1.7 to 4.7 at 220 kVp. Almost no dose enhancement was observed in 6 MV X-ray. The analytical DEFs seemed to be underestimated by averaging local enhancement over the entire active layer. However, analytical DEFs within the ranges of secondary electrons was much higher than the measured macroscopic DEFs. CONCLUSIONS The experimental and analytical approaches developed in this study could quantitatively estimate radioenhancement by GNPs. Due to a short range of low-energy electrons emitted from gold, the microscopic radioenhancement within the ranges of low-energy electrons would be particularly important in a cell.
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Mirza JA, Hernández Millares R, Kim GI, Park SY, Lee J, Ye SJ. Characterization of radiochromic films as a micrometer-resolution dosimeter by confocal Raman spectroscopy. Med Phys 2019; 46:5238-5248. [PMID: 31442302 DOI: 10.1002/mp.13778] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 07/08/2019] [Accepted: 08/12/2019] [Indexed: 11/06/2022] Open
Abstract
PURPOSE Micrometer spatial resolution dosimetry has become inevitable for advanced radiotherapy techniques. A new approach using radiochromic films was developed to measure a radiation dose at a micrometer spatial resolution by confocal Raman spectroscopy. METHODS The commercial radiochromic films (RCF), EBT3 and EBT-XD, were irradiated with known doses using 50, 100, 200, and 300 kVp, and 6-MV x rays. The dose levels ranged from 0.3 to 50 Gy. The Raman mapping technique developed in our early study was used to readout an area of 100 × 100 µm2 on RCF with improved lateral and depth resolutions with confocal Raman spectrometry. The variation in Raman spectra of C-C-C deformation and C≡C stretching modes of diacetylene polymers around 676 and 2060 cm-1 , respectively, as a function of therapeutic x-ray doses, was measured. The single peak (SP) of C≡C and the peak ratio (PR) of C≡C band height to C-C-C band height with a spatial resolution of 10 µm on both types of RCF were evaluated, averaged, and plotted as a function of dose. An achievable spatial resolution, clinically useful dose range, dosimetric sensitivity, dose uniformity, and postirradiation stability as well as the orientation, energy, and dose rate dependence, of both types of RCFs, were characterized by the technique developed in this study. RESULTS A spatial resolution on RCF achieved by SP and PR methods was ~4.5 and ~2.9 µm, respectively. Raman spectroscopy data showed dose nonuniformity of ~11% in SP method and <3% in PR method. The SP method provided dose ranges of up to ~10 and ~20 Gy for EBT3 and EBT-XD films, respectively while the PR method up to ~30 and ~50 Gy. The PR method diminished the orientation effect. The percent difference between landscape and portrait orientations for the EBT3 and the EBT-XD films at 4 Gy had an acceptable level of 1.2% and 2.4%, respectively. With both SP and PR methods, the EBT3 and the EBT-XD films showed weak energy (within ~10% and ~3% for SP and PR methods, respectively) and dose rate dependence (within ~5% and ~3% for SP and PR methods, respectively) and had a stable response after 24-h postirradiation. CONCLUSIONS A technique for micrometer-resolution dosimetry was successfully developed by detecting radiation-induced Raman shift on EBT3 and EBT-XD. Both types of RCFs were suitable for micrometer-resolution dosimetry using CRS. With CRS both lateral and depth resolutions on RCF were improved. The PR method provided superior characteristics in dose uniformity, dose ranges, orientation dependence, and laser effect for both types of RCFs. The overall dosimetric characteristics of the RCFs determined by this technique were similar to those known by optical density scanning. The CRS with the PR method is advantageous over other the traditional scanning systems as a spatial resolution of <10 µm on RCF can be achieved with less deviations.
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Affiliation(s)
- Jamal Ahmad Mirza
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Program in Biomedical Radiation Sciences, Seoul National University, Seoul, 08826, Korea.,Isotope Production Division, Pakistan Institute of Nuclear Science and Technology, Nilore, Islamabad, 44000, Pakistan
| | - Rodrigo Hernández Millares
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Program in Biomedical Radiation Sciences, Seoul National University, Seoul, 08826, Korea
| | - Geon Il Kim
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Program in Biomedical Radiation Sciences, Seoul National University, Seoul, 08826, Korea.,School of Medicine, CHA University, Pocheon, 11160, Korea
| | - So-Yeon Park
- Department of Radiation Oncology, Veterans Health Service Medical Center, Seoul, 05368, Korea
| | - Jaegi Lee
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Program in Biomedical Radiation Sciences, Seoul National University, Seoul, 08826, Korea
| | - Sung-Joon Ye
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Program in Biomedical Radiation Sciences, Seoul National University, Seoul, 08826, Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, 03080, Korea.,Robotics Research Laboratory for Extreme Environments, Advance Institutes of Convergence Technology, Seoul National University, Suwon, 16229, Korea
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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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Talarico OS, Krylova TA, Melnik NN. Raman scattering for dosimetry using
GAFCHROMIC EBT
3 radiochromic dosimetry film. Med Phys 2019; 46:1883-1887. [DOI: 10.1002/mp.13423] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 01/22/2019] [Accepted: 01/22/2019] [Indexed: 11/12/2022] Open
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León‐Marroquín EY, Mulrow DJ, Khan R, Darafsheh A. Spectral analysis of the EBT3 radiochromic films for clinical photon and electron beams. Med Phys 2019; 46:973-982. [DOI: 10.1002/mp.13330] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 11/05/2018] [Accepted: 11/26/2018] [Indexed: 11/05/2022] Open
Affiliation(s)
- Elsa Y. León‐Marroquín
- Department of Radiation Oncology Washington University School of Medicine St. Louis MO 63110 USA
| | - Daniel J. 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
| | - Rao Khan
- Department of Radiation Oncology Washington University School of Medicine St. Louis MO 63110 USA
| | - Arash Darafsheh
- Department of Radiation Oncology Washington University School of Medicine St. Louis MO 63110 USA
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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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