Reference radiochromic film dosimetry: Review of technical aspects

Dević, Slobodan; Tomic, Nada; Lewis, David F.

doi:10.1016/j.ejmp.2016.02.008

Cited by 247 publications

(282 citation statements)

References 62 publications

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“…Radiochromic films have been used widely for two‐dimensional dosimetry in SRS because they have good spatial resolution, energy independent, tissue equivalent, and self‐developing . The main disadvantage of radiochromic films is the post irradiation waiting time …”

Section: Introductionmentioning

confidence: 99%

A 2D silicon detector array for quality assurance in small field dosimetry: DUO

et al. 2017

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Section: Introductionmentioning

confidence: 99%

A 2D silicon detector array for quality assurance in small field dosimetry: DUO

et al. 2017

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“…16 Like their predecessors, EBT3 films are expected to have low energy dependence and their dose response is practically insensitive to changes in the field size, depth and dose. [16][17][18] In addition, they can have a high spatial resolution and can provide two-dimensional (2D) dose distributions. 14 Film pixel value was converted into net optical density (netOD) using single-channel analysis.…”

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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“…Difference in response appears to be air kerma dependent, being larger at lower values. However, one has to keep in mind that the overall uncertainty of measured air kerma (or dose) will be governed by higher measurement uncertainty at lower air kerma values, as reported in the literature not only for the XR‐QA2 film model but for all the radiochromic film dosimetry protocols in general …”

Section: Resultsmentioning

confidence: 99%

“…Film response, measured as the radiation induced change in reflectance, was calculated using pixel values (PV) from the red color channel and net Δ R was calculated for each film piece by subtracting the reflectance of the nonirradiated control film piece from the reflectance of the irradiated one . Calibration curves were generated using a power function while response curves were fitted using rational function and the associated uncertainties were calculated using procedure outlined in Ref …”

Section: Methodsmentioning

confidence: 99%

“…Most of the current radiochromic film dosimetry protocols suggest that films should be scanned at least 8 h postirradiation, which is the time assumed to be necessary for the film darkening to saturate . From the chemical point of view, this is the time after which polymerization process, initiated by absorbed radiation, would slow sufficiently so that variability in the time between film exposure and scanning will not be the source of a substantial dose measurement uncertainty.…”

Section: Introductionmentioning

confidence: 99%

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Technical Note: Response time evolution of XR‐QA2 GafChromic™ film models

et al. 2017

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Purpose: To evaluate the response of the newest XR-QA2 GafChromic TM film model in terms of postexposure signal growth and energy response in comparison with the older XR-QA (Version 2) model. Methods: Pieces of film were irradiated to air kerma in air values up to 12 cGy with several beam qualities (5.3-8.25 mm Al) commonly used for CT scanning. Film response was scored in terms of net reflectance from scanned film images at various points in time postirradiation ranging from 1 to 7 days and 5 months postexposure. To reconstruct the measurement signal changes with postirradiation delay, we irradiated one film piece and then scanned it at different point times starting from 2" min and up to 3 days postexposure. Results: For all beam qualities and dose range investigated, it appears that the XR-QA2 film signal completely saturated after 15 h. Compared to 15 h postirradiation scanning time, the observed variation in net reflectance were 3%, 2%, and 1% for film scanned 2" min, 20 min, and 3 h after exposure, respectively, which is well within the measurement uncertainty of the XR-QA2 based reference radiochromic film dosimetry system. A comparison between the XR-QA (Version 2) and the XR-QA2 film response after several months (relative to their responses after 24 h) show differences in up to 8% and 1% for each film model respectively. Conclusions: The replacement of cesium bromide in the older XR-QA (Version 2) film model with bismuth oxide in the newer XR-QA2 film, while keeping the same single sensitive layer structure, lead to a significantly more stable postexposure response.

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Reference radiochromic film dosimetry: Review of technical aspects

Cited by 247 publications

References 62 publications

A 2D silicon detector array for quality assurance in small field dosimetry: DUO

A 2D silicon detector array for quality assurance in small field dosimetry: DUO

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

Technical Note: Response time evolution of XR‐QA2 GafChromic™ film models

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