GafChromic® EBT3 films for patient specific IMRT QA using a multichannel approach

Marrazzo, L.; Zani, M.; Pallotta, S.; Arilli, C.; Casati, M.; Compagnucci, A.; Talamonti, Cinzia; Bucciolini, M.

doi:10.1016/j.ejmp.2015.08.010

Cited by 41 publications

(29 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Similarly, in a number of studies, the 2%/2 mm criterion was considered more appropriate than the 3%/3 mm one. [ 10 31 32 33 ] For head and neck plans, as well as for prostate, Stasi et al . [ 31 ] used the 2%/2 mm/LD criterion and obtained a mean GPR of 89.4% and 85.0%, respectively, while in the present study, the result obtained was 86.8%.…”

Section: Discussionmentioning

confidence: 99%

Volumetric-modulated arc therapy lung stereotactic body radiation therapy dosimetric quality assurance: A comparison between radiochromic film and chamber array

et al. 2017

View full text Add to dashboard Cite

Introduction:The aim of this work is to verify the use of radiochromic film in the quality assurance (QA) of volumetric-modulated arc therapy (VMAT) lung stereotactic body radiation therapy (SBRT) plans and compare the results with those obtained using an ion chamber array.Materials and Methods:QA was performed for 14 plans using a two-dimensional-array seven29 and EBT3 film. Dose values per session ranged between 7.5 Gy and 18 Gy. The multichannel method was used to obtain a dose map for film.Results:The results obtained were compared with treatment planning system calculated profiles through gamma analysis. Passing criteria were 3%/3 mm, 2%/2 mm and 3%/1.5 mm with maximum and local dose (LD) normalization. Mean gamma passing rate (GPR) (percentage of points presenting a gamma function value of <1) was obtained and compared. Calibration curves were obtained for each color channel within the dose range 0–16 Gy. Mean GPR values for film were >98.9% for all criteria when normalizing per maximum dose. When using LD, normalization was >92.7%. GPR values for the array were lower for all criteria; this difference being statistically significant when normalizing at LD, reaching 12% for the 3%/1.5 mm criterion.Conclusion:Both detectors provide satisfactory results for the QA of plans for VMAT lung SBRT. The film provided greater mean GPR values, afforded greater spatial resolution and was more efficient overall.

show abstract

Section: Discussionmentioning

confidence: 99%

Volumetric-modulated arc therapy lung stereotactic body radiation therapy dosimetric quality assurance: A comparison between radiochromic film and chamber array

et al. 2017

View full text Add to dashboard Cite

show abstract

“…In saturation curves analyses, it was firstly reinforced what had already been studying by others authors: the red channel for NOD evaluation is the more sensitive for doses up to 7 Gy 1,4,13,16 . Once for 14h post-irradiation the saturation reached its maximum for almost all dose levels (including for single-channel analyses) it was chosen as being the new optimal time for scanning after film irradiation.…”

Section: Discussionmentioning

confidence: 65%

“…This is a reflective film digitizer with a spatial resolution of up to 2400 dpi 11 . As it has a three channel CCD detector, it was possible to perform a multichannel dosimetric evaluation of the EBT3 step films, which has demonstrated higher agreement with the experimental measurements and with the treatment planning system than the single channel analyses 12,13 .…”

Section: Scanning and Dosimetric Analysis Proceduresmentioning

confidence: 99%

Issues on VMAT QA Program with EBT3 Radiochromic Films: An improvement proposal

Col¹,

Nagao²,

Santos³

et al. 2019

Rev Bras Fis Med

View full text Add to dashboard Cite

EBT3 radiochromic film is renowned in medical physics field due its dose verification for Quality Assurance (QA) program in intensity-modulated radiotherapy (IMRT). However, it is known that QA programs, which include these films, are expensive and relatively time-consuming. Furthermore, it was noted that dosimetry with EBT3 film has been suffering with lack of accuracy. In that way, it was evaluated its possible dosimetric inaccuracy, the time expenditure in the whole QA process, as well as the cost-benefit of such a program and it is suggested efforts to improve this process based on our institution expertise. A retrospective study was performed on VMATplans, rating how many cases got success by absolute dosimetric Gamma analysis. Furthermore, in order to verify the film intra-lot aging, the calibration curves were compared to the lot fabrication date. On the other hand, with single- and multi-channel dosimetric analyses, further trials were performed over the post-irradiationsaturation curves up to 35 h after irradiation. The retrospective Gamma analyses exhibited that about 23% of the total VMAT cases did not passed by absolute Gamma evaluation. It was seen that the fabrication date influences the dose response, which prerequisites a calibration curve for each film box. For the multichannelanalyses, as excepted, the red channel sensitivity was the highest for doses up to 5 Gy. Moreover, it was reinforced that the dose response is a direct function of dose level for both types of analyses. In that way, it was chosen a post-irradiation time interval of 12h-16h, with dose response variation criteria less than 2%. Finally, it was verified, based on our routine, that there were about 23h/month expended in a film QA program and directly costs bordering US$20,000.00/year.

show abstract

“…Recently, a new and efficient protocol for radiochromic film dosimetry using EBT3 films was published [ 12 ] that combines calibration and measurement in a single scan, and issues related to environmental and scanner variability can be eliminated using this protocol. The optimal application of the protocol was studied by Marrazzo et al [ 33 ], and the effects of environmental and scanner variability were negligible.…”

Section: Discussionmentioning

confidence: 99%

The combination of the error correction methods of GAFCHROMIC EBT3 film

Chen

Zhu

et al. 2017

PLoS ONE

View full text Add to dashboard Cite

PurposeThe aim of this study was to combine a set of methods for use of radiochromic film dosimetry, including calibration, correction for lateral effects and a proposed triple-channel analysis. These methods can be applied to GAFCHROMIC EBT3 film dosimetry for radiation field analysis and verification of IMRT plans.MethodsA single-film exposure was used to achieve dose calibration, and the accuracy was verified based on comparisons with the square-field calibration method. Before performing the dose analysis, the lateral effects on pixel values were corrected. The position dependence of the lateral effect was fitted by a parabolic function, and the curvature factors of different dose levels were obtained using a quadratic formula. After lateral effect correction, a triple-channel analysis was used to reduce disturbances and convert scanned images from films into dose maps. The dose profiles of open fields were measured using EBT3 films and compared with the data obtained using an ionization chamber. Eighteen IMRT plans with different field sizes were measured and verified with EBT3 films, applying our methods, and compared to TPS dose maps, to check correct implementation of film dosimetry proposed here.ResultsThe uncertainty of lateral effects can be reduced to ±1 cGy. Compared with the results of Micke A et al., the residual disturbances of the proposed triple-channel method at 48, 176 and 415 cGy are 5.3%, 20.9% and 31.4% smaller, respectively. Compared with the ionization chamber results, the difference in the off-axis ratio and percentage depth dose are within 1% and 2%, respectively. For the application of IMRT verification, there were no difference between two triple-channel methods. Compared with only corrected by triple-channel method, the IMRT results of the combined method (include lateral effect correction and our present triple-channel method) show a 2% improvement for large IMRT fields with the criteria 3%/3 mm.

show abstract

GafChromic® EBT3 films for patient specific IMRT QA using a multichannel approach

Cited by 41 publications

References 30 publications

Volumetric-modulated arc therapy lung stereotactic body radiation therapy dosimetric quality assurance: A comparison between radiochromic film and chamber array

Volumetric-modulated arc therapy lung stereotactic body radiation therapy dosimetric quality assurance: A comparison between radiochromic film and chamber array

Issues on VMAT QA Program with EBT3 Radiochromic Films: An improvement proposal

The combination of the error correction methods of GAFCHROMIC EBT3 film

Contact Info

Product

Resources

About