Radiochromic film dosimetry: Reflection vs transmission scanning

Kalef-Ezra, J.; Karava, K.

doi:10.1118/1.2919092

Cited by 27 publications

(21 citation statements)

References 27 publications

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“…The films were kept in a light‐proof container when not being analyzed to reduce coloration from ambient light and UV sources 12 , 13 . Scans were performed at 50 pixels per inch resolution and analysis was performed using the red channel, per normal Gafchromic film analysis techniques 14 , 15 . This meant that pixel density values for analysis where 16 bit (65536) data.…”

Section: Methodsmentioning

confidence: 99%

Comparison of Epson scanner quality for radiochromic film evaluation

Alnawaf

Butson

2012

J Applied Clin Med Phys

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Epson Desktop scanners have been quoted as devices which match the characteristics required for the evaluation of radiation dose exposure by radiochromic films. Specifically, models such as the 10000XL have been used successfully for image analysis and are recommended by ISP for dosimetry purposes. This note investigates and compares the scanner characteristics of three Epson desktop scanner models including the Epson 10000XL, V700, and V330. Both of the latter are substantially cheaper models capable of A4 scanning. As the price variation between the V330 and the 10000XL is 20‐fold (based on Australian recommended retail price), cost savings by using the cheaper scanners may be warranted based on results. By a direct comparison of scanner uniformity and reproducibility we can evaluate the accuracy of these scanners for radiochromic film dosimetry. Results have shown that all three scanners can produce adequate scanner uniformity and reproducibility, with the inexpensive V330 producing a standard deviation variation across its landscape direction of 0.7% and 1.2% in the portrait direction (reflection mode). This is compared to the V700 in reflection mode of 0.25% and 0.5% for landscape and portrait directions, respectively, and 0.5% and 0.8% for the 10000XL. In transmission mode, the V700 is comparable in reproducibility to the 10000XL for portrait and landscape mode, whilst the V330 is only capable of scanning in the landscape direction and produces a standard deviation in this direction of 1.0% compared to 0.6% (V700) and 0.25% (10000XL). Results have shown that the V700 and 10000XL are comparable scanners in quality and accuracy with the 10000XL obviously capable of imaging over an A3 area as opposed to an A4 area for the V700. The V330 scanner produced slightly lower accuracy and quality with uncertainties approximately twice as much as the other scanners. However, the results show that the V330 is still an adequate scanner and could be used for radiation dosimetry purposes. As such, if budgetary requirements are limited, the V700 scanner would be the recommended option at a price eight times cheaper than the 10000XL; however, the V330 produces adequate results at a price which is 2.5 times cheaper again. This may be a consideration for smaller institutions or individuals working with radiochromic film dosimetry.PACS number: 87.55.Qr; 87.56.Fc

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Section: Methodsmentioning

confidence: 99%

Comparison of Epson scanner quality for radiochromic film evaluation

Alnawaf

Butson

2012

J Applied Clin Med Phys

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“…38 The fitting method has been used to obtain the relationship between dose and calibration data. 39 For IMRT plan verification, we used gamma index settings of 3% in dose and 3 mm in distance to get an agreement for most clinical environments. 40 As the films are placed very close to the lamp of the scanner, which can be one contributor of UV light, we scanned the films under the same conditions with respect to number of scans, area of ROI, and interval between successive readings.…”

Section: Iie Effect Of Room Lightmentioning

confidence: 99%

Variations in dose distribution and optical properties of Gafchromic^TM EBT2 film according to scanning mode

et al. 2012

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The transmission scanning mode exhibited a strong dependence on film orientation during scanning and a change in optical density resulting from room light exposure, so a constant scanning orientation and minimal exposure to light can reduce uncertainty in the measured dose (23 ± 3%). The angular dependence was analyzed using Jones matrices and optical properties of EBT2 film were obtained using an ellipsometer and an UV/visible spectrometer. The reflection scanning mode has relatively good stability with respect to room light and film orientation on a scanner, although the large standard deviation of dose is a disadvantage in measurements of absolute dose. Reflection scanning mode can offer a potential advantage for film dosimetry in radiotherapy, although transmission scanning mode is still recommended for dosimetry as it provides better uncertainty results.

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“…Because EBT film is not rendered completely opaque by irradiation, both reflectance and transmission scanning can be performed. Kalef-erza et al (2008) [17] compared these two scanning techniques and assessed reflection mode to be superior for accuracy especially at lower doses. However, both transmission scanning and reflectance scanning still produce a non-uniformity in scanner response which appears to be due to scattering of light within the scanner, especially at the scanning edges.…”

Section: Introductionmentioning

confidence: 98%

Scanner uniformity improvements for radiochromic film analysis with matt reflectance backing

Butson¹,

Alnawaf

et al. 2011

Australas Phys Eng Sci Med

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A simple and reproducible method for increasing desktop scanner uniformity for the analysis of radiochromic films is presented. Scanner uniformity, especially in the non-scan direction, for transmission scanning is well known to be problematic for radiochromic film analysis and normally corrections need to be applied. These corrections are dependant on scanner coordinates and dose level applied which complicates dosimetry procedures. This study has highlighted that using reflectance scanning in combination with a matt, white backing material instead of the conventional gloss scanner finish, substantial increases in the scanner uniformity can be achieved within 90% of the scanning area. Uniformity within ±1% over the scanning area for our epsonV700 scanner tested was found. This is compared to within ±3% for reflection scanning with the gloss backing material and within ±4% for transmission scanning. The matt backing material used was simply 5 layers of standard quality white printing paper (80 g/m(2)). It was found that 5 layers was the optimal result for backing material however most of the improvements were seen with a minimum of 3 layers. Above 5 layers, no extra benefit was seen. This may eliminate the need to perform scanner corrections for position on the desktop scanners for radiochromic film dosimetry.

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Radiochromic film dosimetry: Reflection vs transmission scanning

Cited by 27 publications

References 27 publications

Comparison of Epson scanner quality for radiochromic film evaluation

Comparison of Epson scanner quality for radiochromic film evaluation

Variations in dose distribution and optical properties of Gafchromic^TM EBT2 film according to scanning mode

Scanner uniformity improvements for radiochromic film analysis with matt reflectance backing

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Radiochromic film dosimetry: Reflection vs transmission scanning

Cited by 27 publications

References 27 publications

Comparison of Epson scanner quality for radiochromic film evaluation

Comparison of Epson scanner quality for radiochromic film evaluation

Variations in dose distribution and optical properties of GafchromicTM EBT2 film according to scanning mode

Scanner uniformity improvements for radiochromic film analysis with matt reflectance backing

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Product

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About

Variations in dose distribution and optical properties of Gafchromic^TM EBT2 film according to scanning mode