Raman scattering for dosimetry using <scp>GAFCHROMIC EBT</scp>3 radiochromic dosimetry film

Talarico, O. S.; Krylova, T. A.; Mel’nik, N. N.

doi:10.1002/mp.13423

Cited by 4 publications

(10 citation statements)

References 23 publications

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“…Over the last few decades, different types of radiochromic films with a resolution of fewer than 100 µm have been investigated using an optical scanner or a densitometer, as explained in more detail elsewhere . The spectral response of radiochromic films has been explored to find out new and improved readout systems for high‐spatial resolution dosimetry . In the previous study, we developed a novel Raman mapping technique to measure the variation in Raman spectra of carbon double (C = C) and triple (C≡C) stretching bands of diacetylene polymer as a function of therapeutic x‐ray doses with a high‐spatial resolution .…”

Section: Introductionmentioning

confidence: 99%

“…In the previous study, we developed a novel Raman mapping technique to measure the variation in Raman spectra of carbon double (C = C) and triple (C≡C) stretching bands of diacetylene polymer as a function of therapeutic x‐ray doses with a high‐spatial resolution . Recently, Talarico et al performed a similar Raman mapping technique on EBT3 film with a 40‐µm spatial resolution and observed that the ratio of the peak intensities of C = C stretching mode around 1450 cm −1 and CH 2 vibrations around 1330 cm −1 grows with the increase in radiation dose . Reading out with Raman spectroscopy was advantageous in the sense that any delicate chemical changes caused by radiation can be detected.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of radiochromic films as a micrometer‐resolution dosimeter by confocal Raman spectroscopy

et al. 2019

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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 9 100 µm 2 on RCF with improved lateral and depth resolutions with confocal Raman spectrometry. The variation in Raman spectra of C-C-C deformation and CC stretching modes of diacetylene polymers around 676 and 2060 cm À1 , respectively, as a function of therapeutic x-ray doses, was measured. The single peak (SP) of CC and the peak ratio (PR) of CC 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 5238 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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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characterization of radiochromic films as a micrometer‐resolution dosimeter by confocal Raman spectroscopy

et al. 2019

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“…Dosimeters such as ionization chambers, films, thermoluminescent dosimeter (TLD), metal oxide semiconductor field‐effect transistor (MOSFET)‐based devices, and silicon diode detectors have been developed for this purpose. However, they often fall short of energy dependence, tissue equivalence, or spatial resolution 1,2,3 . In particular, measuring the dose distribution at the micrometer scale has been a challenge in radiation dosimetry.…”

Section: Introductionmentioning

confidence: 99%

“…Usually, radiochromic films are examined through optical densitometers to measure shifts in their optical density for different doses. Recent studies have used Raman spectroscopy to determine the compositional changes in the radiochromic film structure due to the polymerization of LiPCDA monomers 1.4–8 . Due to such favorable characteristics, RCF has been widely used for dose measurements in radiation therapy.…”

Section: Introductionmentioning

confidence: 99%

“…However, they often fall short of energy dependence, tissue equivalence, or spatial resolution. 1,2,3 In particular, measuring the dose distribution at the micrometer scale has been a challenge in radiation dosimetry. Radiochromic films (RCF) have been widely employed and further studied to address this issue, especially in small field dosimetry.…”

Section: Introductionmentioning

confidence: 99%

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Radiosensitization by Au‐nanofilm at micrometer level using confocal Raman spectroscopy

et al. 2021

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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 µm 2. 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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High spatial resolution dosimetry with uncertainty analysis using Raman micro‐spectroscopy readout of radiochromic films

et al. 2021

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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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Raman scattering for dosimetry using GAFCHROMIC EBT3 radiochromic dosimetry film

Cited by 4 publications

References 23 publications

Characterization of radiochromic films as a micrometer‐resolution dosimeter by confocal Raman spectroscopy

Characterization of radiochromic films as a micrometer‐resolution dosimeter by confocal Raman spectroscopy

Radiosensitization by Au‐nanofilm at micrometer level using confocal Raman spectroscopy

High spatial resolution dosimetry with uncertainty analysis using Raman micro‐spectroscopy readout of radiochromic films

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