Evaluation of a LED-based flatbed document scanner for radiochromic film dosimetry in transmission mode

Lárraga‐Gutiérrez, José M.; García‐Garduño, Olivia Amanda; Treviño‐Palacios, Carlos G.; Herrera-González, José Alfredo

doi:10.1016/j.ejmp.2018.02.010

Cited by 23 publications

(27 citation statements)

References 20 publications

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“…, only three maps showed good homogeneity level (within 2%) for a whole sheet scanning:

n P V_{italicRGB}

n e t O D_{G},

and

n e t O D_{B}

, although, the use of

n e t O D_{B}

is discouraged because of its inaccuracy. The red channel especially showed strong spatial dependency which agrees with the work of Lárraga‐Gutiérrez et al with an LED‐based scanner (although to a less extent, 8%). It is important to mention that most of the available literature on lateral scan correction are based on xenon fluorescent lamps so comparison to them would not be meaningful especially that the dose levels are different.…”

Section: Discussionsupporting

confidence: 89%

“…The red channel especially showed strong spatial dependency which agrees with the work of Lárraga‐Gutiérrez et al with an LED‐based scanner (although to a less extent, 8%). It is important to mention that most of the available literature on lateral scan correction are based on xenon fluorescent lamps so comparison to them would not be meaningful especially that the dose levels are different. However, quantitatively, results of this study support the conclusion that the lateral scan correction seems to be more severe for LED‐based scanners in the red channel only, since it was shown that for the green and blue channels, it is correctable with the use of specific control.…”

Section: Discussionsupporting

confidence: 89%

“…In this study, only results from the 12000XL scanner were reported since other studies already addressed xenon fluorescent lamp‐based scanners . The changes seen in Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore,

n P V_{italicRGB}

with the “fingerprint” correction protocol was shown to reduce the scanner variation consistently at all examined dose levels, which could be an indication for the potential effect of continuous scanning medium on the film signal. Lárraga‐Gutiérrez et al compared the use of an LED scanner (EPSON V800) to that of a xenon fluorescent lamp (EPSON 11000 XL). They reported no significant changes for both scanners after the 5th scan when used to scan EBT3 films model, which is not in full disagreement with results of this study since most “appreciable” changes started to appear approximately after scan#40 in this study to a level of 2.0%–2.5% after 100 scans (after correction).…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, it is possible that already‐established accuracy levels with the current RCF dosimetry systems may be impacted by such changes and these new scanners must be tested thoroughly. Lárraga‐Gutiérrez et al evaluated the performance of the V800 LED scanner and compared its use to the 11000XL model. They concluded that the response of the V800 scanner was comparable to the 11000XL but they noted some important spectral differences between the two types of lamps.…”

Section: Introductionmentioning

confidence: 99%

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Dose–response linearization in radiochromic film dosimetry based on multichannel normalized pixel value with an integrated spectral correction for scanner response variations

et al. 2019

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Purpose: To introduce a model that reproducibly linearizes the response from radiochromic film (RCF) dosimetry systems at extended dose range. To introduce a correction method, generated from the same scanned images, which corrects for scanner temporal response variation and scanner bed inhomogeneity. Methods: Six calibration curves were established for different lot numbers of EBT3 GAFCHRO-MIC TM film model based on four EPSON scanners [10000XL (2 units), 11000XL, 12000XL] at three different centers. These films were calibrated in terms of absorbed dose to water based on TG51 protocol or TRS398 with dose ranges up to 40 Gy. The film response was defined in terms of a proposed normalized pixel value (nPV RGB ) as a summation of first-order equations based on information from red, green, and blue channels. The fitting parameters of these equations are chosen in a way that makes the film response equal to dose at the time of calibration. An integrated set of correction factors (one per color channel) was also introduced. These factors account for the spatial and temporal changes in scanning states during calibration and measurements. The combination of nPV RGB and this "fingerprint" correction formed the basis of this new protocol and it was tested against net optical density (netOD X¼R;G;B ) single-channel dosimetry in terms of accuracy, precision, scanner response variability, scanner bed inhomogeneity, noise, and long-term stability. Results: Incorporating multichannel features (RGB) into the normalized pixel value produced linear response to absorbed dose (slope of 1) in all six RCF dosimetry systems considered in this study. The "fingerprint" correction factors of each of these six systems displayed unique patterns at the time of calibration. The application of nPV RGB to all of these six systems could achieve a level of accuracy of AE 2.0% in the dose range of interest within modeled uncertainty level of 2.0%-3.0% depending on the dose level. Consistent positioning of control and measurement film pieces and integrating the multichannel correction into the response function formalism mitigated possible scanner response variations of as much as AE 10% at lower doses and scanner bed inhomogeneity of AE 8% to the established level of uncertainty at the time of calibration. The system was also able to maintain the same level of accuracy after 3 and 6 months post calibration.Conclusions: Combining response linearity with the integrated correction for scanner response variation lead to a sustainable and practical RCF dosimetry system that mitigated systematic response shifts and it has the potential to reduce errors in reporting relative information from the film response.

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“…, only three maps showed good homogeneity level (within 2%) for a whole sheet scanning:

n P V_{italicRGB}

n e t O D_{G},

and

n e t O D_{B}

, although, the use of

n e t O D_{B}

Section: Discussionsupporting

confidence: 89%

Section: Discussionsupporting

confidence: 89%

“…In this study, only results from the 12000XL scanner were reported since other studies already addressed xenon fluorescent lamp‐based scanners . The changes seen in Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore,

n P V_{italicRGB}

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Dose–response linearization in radiochromic film dosimetry based on multichannel normalized pixel value with an integrated spectral correction for scanner response variations

et al. 2019

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Lateral response artifact correction method using image stitching technique in radiochromic film dosimetry

Miura,

Miyazawa,

Ozawa

et al. 2024

J Applied Clin Med Phys

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PurposeLateral response artifact (LRA) is caused by the interaction between film and flatbed scanner in the direction perpendicular to the scanning direction. This can significantly affect the accuracy of patient‐specific quality assurance (QA) in cases involving large irradiation fields. We hypothesized that by utilizing the central area of the flatbed scanner, where the magnitude of LRA is relatively small, the LRA could be mitigated effectively. This study proposes a practical solution using the image‐stitching technique to correct LRA for patient‐specific QA involving large irradiation fields.MethodsGafchromic™ EBT4 film and Epson Expression ES‐G11000 flatbed scanner were used in this study. The image‐stitching algorithm requires a spot between adjacent images to combine them. The film was scanned at three locations on a flatbed scanner, and these images were combined using the image‐stitching technique. The combined film dose was then calculated and compared with the treatment planning system (TPS)‐calculated dose using gamma analysis (3%/2 mm). Our proposed LRA correction was applied to several films exposed to 18 × 18 cm2 open fields at doses of 200, 400, and 600 cGy, as well as to four clinical Volumetric Modulated Arc Therapy (VMAT) treatment plans involving large fields.ResultsFor doses of 200, 400, and 600 cGy, the gamma analysis values with and without LRA corrections were 95.7% versus 67.8%, 95.5% versus 66.2%, and 91.8% versus 35.9%, respectively. For the clinical VMAT treatment plan, the average pass rate ± standard deviation in gamma analysis was 94.1% ± 0.4% with LRA corrections and 72.5% ± 1.5% without LRA corrections.ConclusionsThe effectiveness of our proposed LRA correction using the image‐stitching technique was demonstrated to significantly improve the accuracy of patient‐specific QA for VMAT treatment plans involving large irradiation fields.

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Temperature dependence and temporal stability of stacked radiochromic sheets for three‐dimensional dose verification

et al. 2020

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Purpose Recently a novel radiochromic sheet dosimeter, termed as PRESAGE sheets, consisting of leuco crystal violet dye and radical initiator had been developed and characterized. This study examines the dosimeter’s temporal stability and storage temperature dependence postirradiation, and its applicability for dose verification in three dimensions (3D) as a stack dosimeter. Methods PRESAGE sheets were irradiated using 6 MV photons at a dose range of 0–20 Gy with the change in optical density measured using a flatbed scanner. Following their irradiation, PRESAGE sheets were stored in different temperature environments (–18 °C, 4 °C, and 22 °C) and scanned at different time points, ranging from 1 to 168 h postirradiation, to track changes in measured signal and linearity of dose response. Multiple PRESAGE sheets were bound together to create a 12 × 13 × 8.7 cm3 film stack, with EBT3 film inserted between the sheets in the central region of the stack, that was treated using a clinical VMAT plan. Based on the results from the time and storage temperature study, two‐dimensional (2D) relative dose distribution measurements in PRESAGE were acquired promptly following irradiation at selected planes in the coronal, sagittal, and axial orientation of the film stack and compared to the treatment planning system calculations in their respective axes. Dose distribution measurements on the coronal axis of the stack dosimeter were also independently verified using EBT3 film. Results The dose response was observed to be linear (R2> 0.995) with sheets stored in colder temperatures retaining their signal and dose response sensitivity for extended periods postirradiation. Sheets stored in 22 °C environment should be measured within an hour postirradiation. Sheets stored in a 4 °C and −18 °C environment can be scanned up to 20‐ and 72 h postirradiation, respectively, while preserving the integrity of their dose response sensitivity and linearity of dose response within a mean absolute percent error of 2.0%. For instance, at 20 h postirradiation the dose response sensitivity for sheets stored in a −18 °C, 4 °C, and 22 °C temperature environment was measured to be 97%, 91%, and 77% of their original values measured within an hour postirradiation, respectively. The 2D gamma pass rate for central slices exceed 95% for PRESAGE film stack compared with treatment planning system on selected planes in the axial, coronal, and sagittal orientation and EBT3 film in the coronal orientation using a 2D gamma index of 2%/2mm. The gamma pass rate in comparing the calculated dose distribution with the measured dose distribution from PRESAGE‐LCV was observed to decrease in sheets scanned at later elapsed times postirradiation. In one example, the gamma pass rate for 2%/2mm criteria in the coronal plane was observed to decrease from 97.7% pass rate when scanned within an hour postirradiation to 92.1% pass rate when scanned at 20 h postirradiation under room temperature conditions. Conclusions This is the first study to demonstrate that the temporal s...

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Evaluation of a LED-based flatbed document scanner for radiochromic film dosimetry in transmission mode

Cited by 23 publications

References 20 publications

Dose–response linearization in radiochromic film dosimetry based on multichannel normalized pixel value with an integrated spectral correction for scanner response variations

Dose–response linearization in radiochromic film dosimetry based on multichannel normalized pixel value with an integrated spectral correction for scanner response variations

Lateral response artifact correction method using image stitching technique in radiochromic film dosimetry

Temperature dependence and temporal stability of stacked radiochromic sheets for three‐dimensional dose verification

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