Physical and radiological properties of radiochromic gel as of its composition

Lee, Sang Hoon; Kim, Juree; Shim, Su Jung; Chang, Kyung Hwan; Lim, Sangwook; Huh, Hyun Do; Shin, Dong Oh; Cho, Sam Ju

doi:10.3938/jkps.64.1063

Cited by 6 publications

(7 citation statements)

References 25 publications

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“…Further experiments in-house found a ~10% fading effect that in certain conditions could be interpreted as an effective dose rate effect. Other groups have found no dose rate effect for this initial formulation [3][4][5]. Recent large volume samples are measuring a dose rate effect of nearly +15% for increasing dose rate from 1 to 10 Gy/min.…”

Section: Introductionmentioning

confidence: 85%

Dose rate effects in radiochromic leuco crystal violet dosimeters

Jordan

2022

J. Phys.: Conf. Ser.

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Radiochromic dosimeters based on leuco crystal violet (LCV) in aqueous solutions and gelatin hydrogels were evaluated for dose and dose rate performance. Optical transmission measurements were performed on samples in custom 10 cm long cuvettes in order to have measurable signals below 10 Gy. Standard gel formulations with 0.7 mM concentration of anionic surfactant sodium dodecyl sulfate (SDS) had a dose rate effect of increasing sensitivity with increasing dose rate of nearly 15% from 1 to 10 Gy/min at 20 Gy. Solutions of LCV and trichloracetic acid also showed similar dose rate effects. Adding LCV increased dose rate effect. Adding SDS, lowered sensitivity but maintained dose rate effect. Adding 0.4% gelatin also lowered sensitivity but reversed dose rate effect. For gels, lowering the pH reduced both sensitivity and dose rate effect. These trends are consistent with LCV solubility contributing to dose rate effects. These data indicate there are several factors related to dose rate effects in leuco crystal violet dosimeters and formulations designed to maximize sensitivity may not minimize dose rate effects.

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Section: Introductionmentioning

confidence: 85%

Dose rate effects in radiochromic leuco crystal violet dosimeters

Jordan

2022

J. Phys.: Conf. Ser.

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“…The absorbance peak of reusable LMG gel dosimeter was measured at 630∼635 nm and differed with the LCV gel dosimeter peak at 600 nm. 16) Based on wavelength peak data, every group was selected standard wavelength to measure in certain absorbance.…”

Section: Optical Spectrummentioning

confidence: 99%

Analysis of Physical Properties for Various Compositions of Reusable LMG and LCV Micelle Gel

et al. 2016

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In this study, we evaluated the reusable leuco malachite green (LMG) micelle gel properties dependent on various components of chemical concentration and compared with leuco crystal violet (LCV). The gels were delivered to 10, 20, 30, 40 and 50 Gy at 6 MV photon beam from linear accelerator and analyzed using spectrophotometry. We confirmed that the reusable LMG and LVC absorbance wavelength peak were made up at 630 nm and 600 nm respectively. The transparency of reusable LMG decreased with higher amount of trichloroacetic acid (TCAA) and lower reusable LMG dyes. 1 mM reusable LMG was the lowest transparency. The sensitivity was increased depending on lower trichloroacetic acid (TCAA) concentrations and the amount of suitable surfactant (Triton X-100), which was found to be 7 mM. However, we were not able to investigate sensitivity effects factor from reusable LMG dyes. The gel dosimeter containing 16 mM TCAA, 7 mM Triton X-100 gel dosimeter showed the highest sensitivity at 0.0021±0.0001 cm. The sensitivity of LCV was found to be higher than reusable LMG at 0.0037±0.0005 cm. The reusable LMG and LCV dose responses were shown to be R 2 =0.997, R 2 =0.999 respectively, as stable measurement results. Future research is necessary to improve dose sensitivity, dose rate dependency and gel fading with extensive chemical formulations.

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“…Radiochromic gels can be manufactured in an open air environment with non-toxic materials and they absorb rather than scatter light, which facilitates high accuracy readout by optical CT [18]. Furthermore, radiochromic dosimeters possess high dose sensitivity that can be adjusted by changing the proportions of the dye and initiating agent [19].…”

Section: Introductionmentioning

confidence: 99%

Iterative image reconstruction algorithm analysis for optical CT radiochromic gel dosimetry

Collins,

Ogilvy,

Hare

et al. 2024

Biomed. Phys. Eng. Express

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Background: Gel dosimeters are a potential tool for measuring the complex dose distributions that characterize modern radiotherapy. A prototype tabletop solid-tank fan-beam optical CT scanner for readout of gel dosimeters was recently developed. This scanner does not have a straight raypath from source to detector, thus images cannot be reconstructed using filtered backprojection (FBP) and iterative techniques are required. Purpose: To compare a subset of top performing algorithms in terms of image quality and quantitatively determine the optimal algorithm while accounting for refraction within the optical CT system.Methods: A ray tracing simulator was developed to track the path of light rays as they traverse the different mediums of the optical CT scanner. Two clinical phantoms and several synthetic phantoms were produced and used to evaluate the reconstruction techniques under known conditions. Reconstructed images were analyzed in terms of spatial resolution, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), signal non-uniformity (SNU) and mean relative difference (MRD). We developed an image quality based method to find the optimal stopping iteration window for each algorithm. Imaging data from the prototype optical CT scanner was reconstructed and analysed to determine the optimal algorithm for this application. Results/Conclusions: The optimal algorithms found through the quantitative scoring metric were FISTA-TV and S-CG-2-NA. Both algorithms are stable from over iterating and have excellent edge detection. FISTA-TV had the greatest noise reduction, however low spatial resolution makes FISTA-TV only viable for large field dosimetry. S-CG-2-NA has better spatial resolution than FISTA-TV but less noise reduction. S-CG-2-NA still maintains good SNR, CNR, and SNU values thus, is a well rounded reconstruction algorithm that would be the preferable choice for small field dosimetry.

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Physical and radiological properties of radiochromic gel as of its composition

Cited by 6 publications

References 25 publications

Dose rate effects in radiochromic leuco crystal violet dosimeters

Dose rate effects in radiochromic leuco crystal violet dosimeters

Analysis of Physical Properties for Various Compositions of Reusable LMG and LCV Micelle Gel

Iterative image reconstruction algorithm analysis for optical CT radiochromic gel dosimetry

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