Reference dosimetry using radiochromic film

Girard, Frédéric; Bouchard, Hugo; Lacroix, Frédéric

doi:10.1120/jacmp.v13i6.3994

Cited by 38 publications

(54 citation statements)

References 31 publications

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“…23 On subsequent calibrations, irradiations were performed only with films placed at the surface, as the D s /D max ratio was already known, and the films were intended to assess surface doses. Girard et al 23 reported dose differences of up to 3.5% in the red channel for EBT2 films and calibration curves obtained 3 months apart. In this work, the difference between consecutive calibration curves obtained 4-5 months apart for EBT3 films was 3-4% for the red channel and 1.5-2% for the green channel.…”

Section: Film Calibration and Read-outmentioning

confidence: 99%

In vivodosimetry using Gafchromic films during pelvic intraoperative electron radiation therapy (IOERT)

Costa¹,

Sarmento²,

Gomes³

et al. 2016

BJR

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Objective: To characterize in vivo dose distributions during pelvic intraoperative electron radiation therapy (IOERT) for rectal cancer and to assess the alterations introduced by irregular irradiation surfaces in the presence of bevelled applicators. Methods: In vivo measurements were performed with Gafchromic films during 32 IOERT procedures. 1 film per procedure was used for the first 20 procedures. The methodology was then optimized for the remaining 12 procedures by using a set of 3 films. Both the average dose and two-dimensional dose distributions for each film were determined. Phantom measurements were performed for comparison. Results: For flat and concave surfaces, the doses measured in vivo agree with expected values. For concave surfaces with step-like irregularities, measured doses tend to be higher than expected doses. Results obtained with three films per procedure show a large variability along the irradiated surface, with important differences from expected profiles. These results are consistent with the presence of surface hotspots, such as those observed in phantoms in the presence of step-like irregularities, as well as fluid build-up. Conclusion: Clinical dose distributions in the IOERT of rectal cancer are often different from the references used for prescription. Further studies are necessary to assess the impact of these differences on treatment outcomes. In vivo measurements are important, but need to be accompanied by accurate imaging of positioning and irradiated surfaces. Advances in knowledge: These results confirm that surface irregularities occur frequently in rectal cancer IOERT and have a measurable effect on the dose distribution.

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Section: Film Calibration and Read-outmentioning

confidence: 99%

In vivodosimetry using Gafchromic films during pelvic intraoperative electron radiation therapy (IOERT)

Costa¹,

Sarmento²,

Gomes³

et al. 2016

BJR

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“…Recent publications proposed elegant solutions to this limitation, for example Girard et al [13] and Crijns et al [17]. These kinds of investigations are outside the scope of this work, since our purpose is to report about our experience with commercially available software and "plug and play" solution.…”

Section: Discussionmentioning

confidence: 99%

“…Radiochromic films are better stored in a dry and dark environment. Girard et al [13] reported a maximum rate of optical density change of ±0.15% per C in the red channel. They also showed that relative humidity variations ranging from 80% to 20% could introduce dose errors of up to 15%.…”

Section: Radiochromic Film and Scanner Models Usedmentioning

confidence: 99%

Gafchromic film dosimetry: Four years experience using FilmQA Pro software and Epson flatbed scanners

2014

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a b s t r a c tPurpose: s: To assess performance of FilmQA Pro software for pre-treatment patient-specific quality assurance (QA), using radiochromic films and two commercial flatbed scanners. To evaluate a novel multichannel approach compared to the classical red channel evaluation. Material and methods: Patient films (mostly EBT2 films, one box of EBT3) were digitalized using successively two flatbed scanners: the A4-size Epson V750 and the A3-size Epson 10000XL. Prior to patient dose verification, basic characteristics of films and scanners were investigated. Patient films were analyzed using FilmQA Pro software, which enables to use the signal from all three colour channels (Red, Green, Blue). Results: Compared to the red channel evaluation, multichannel evaluation presents better passing rates with regard to local gamma index. As expected, we obtained better results using A3-size scanner compared to A4-size scanner, especially when considering large region of interest. An observation of great interest was made for both scanners: after intensive use, a tilting in the blue transmittance profiles appeared in the lamp direction, making multichannel analysis unsuitable for accurate dose evaluation.

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“…The present task was divided into two parts, namely, (1) the atomic scale model and (2) the macroscopic scale model, in which molecular dynamics (MD) and finite element method (FEM) simulation techniques were coupled. The active layer in the EBT3 film consisted of diacetylene (DA) pentacosa-10,12-diynoate monomers [20] (hereafter referred to as DA monomers), which were modelled using the MD technique. The degrees of SSP in the atomic scale upon different UV exposures were obtained in order to determine the absorption coefficients of the active layer, which were then input into the FEM model.…”

Section: Atomic Scale Modelmentioning

confidence: 99%

“…The active layer in the EBT3 film consisted of diacetylene (DA) pentacosa-10,12-diynoate monomers [20] (hereafter referred to as DA monomers), which were modelled using the MD technique. The degrees of SSP in the atomic scale upon different UV exposures were obtained in order to determine the absorption coefficients of the active layer, which were then input into the FEM model.…”

Section: Introductionmentioning

confidence: 99%

Modeling Coloration of a Radiochromic Film with Molecular Dynamics-Coupled Finite Element Method

et al. 2017

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Radiochromic films change color upon exposures to radiation doses as a result of solid-state polymerization (SSP). Commercially available radiochromic films are primarily designed for, and have become widely used in, clinical X-ray dosimetry. However, many intriguing properties of radiochromic films are not yet fully understood. The present work aimed at developing a theoretical model at both atomic and macroscopic scales to provide a platform for future works to understand these intriguing properties. Despite the fact that radiochromic films were primarily designed for clinical X-ray dosimetry, dose-response curves for the Gafchromic EBT3 film obtained for ultraviolet (UV) radiation were employed to develop our model in order to avoid complications of ionization, non-uniform energy deposition, as well as dispersed doses caused by secondary electrons set in motion by the indirectly ionizing X-ray photons, which might introduce added uncertainties to the model and overshadow the basic SSP processes. The active layer in the EBT3 film consisted of diacetylene (DA) pentacosa-10,12-diynoate monomers, which were modelled using molecular dynamics (MD). The degrees of SSP in the atomic scale upon different UV exposures were obtained to determine the absorption coefficients of the active layer, which were then input into the finite element method (FEM). The classical steady-state Helmholtz equation was engaged to model the reflection from the active layer using the FEM technique. The multifrontal massively parallel sparse direct solver (MUMPS) was employed to solve the present numerical problem. Very good agreement between experimentally and theoretically obtained coloration in terms of net reflective optical density was achieved for different UV exposures. In particular, for UV exposures larger than~40 J/cm 2 , the reflected light intensity decreased at a lower rate when compared to other UV exposure values, which was explained by the densely cross-linked structure under near-complete polymerization, and thus the lower efficiency for further bond formation between DA monomer strands.

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Reference dosimetry using radiochromic film

Cited by 38 publications

References 31 publications

In vivodosimetry using Gafchromic films during pelvic intraoperative electron radiation therapy (IOERT)

In vivodosimetry using Gafchromic films during pelvic intraoperative electron radiation therapy (IOERT)

Gafchromic film dosimetry: Four years experience using FilmQA Pro software and Epson flatbed scanners

Modeling Coloration of a Radiochromic Film with Molecular Dynamics-Coupled Finite Element Method

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