Scanner uniformity improvements for radiochromic film analysis with matt reflectance backing
Tóm tắt
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/m2). 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.
Tài liệu tham khảo
Butson MJ, Cheung T, Yu PKN (2006) Weak energy dependence of EBT Gafchromic film dose response in the 50 kVp–10 MVp X-ray range. Appl Radiat Isot 64:60–62
Cheung T, Butson MJ, Yu PKN (2006) Independence of calibration curves for EBT Gafchromic films of the size of high-energy X-ray fields. Appl Radiat Isot 64:1027–1030
Gotanda T, Katsuda T, Gotanda R, Tabuchi A, Yamamoto K, Kuwano T, Yatake H, Takeda Y (2009) Evaluation of effective energy for QA and QC: measurement of half-value layer using radiochromic film density. Australas Phys Eng Sci Med 32(1):26–29
Gotanda R, Katsuda T, Gotanda T, Tabuchi A, Yatake H, Takeda Y (2008) Dose distribution in pediatric CT head examination using a new phantom with radiochromic film. Australas Phys Eng Sci Med 31(4):339–344
Gotanda R, Katsuda T, Gotanda T, Eguchi M, Takewa S, Tabuchi A, Yatake H (2007) Computed tomography phantom for radiochromic film dosimetry. Australas Phys Eng Sci Med 30(3):194–199
Butson MJ, Cheung T, Yu PK (2007) Radiochromic film for verification of superficial X-ray backscatter factors. Australas Phys Eng Sci Med 30:269–273
Currie M, Bailey M, Butson M, Martin J (2007) Verification of nose irradiation using orthovoltage x-ray beams. Australas Phys Eng Sci Med 30:105–110
He CF, Geso M, Ackerly T, Wong CJ (2008) Stereotactic dose perturbation from an aneurysm clip measured by Gafchromic EBT film. Australas Phys Eng Sci Med 31:18–23
Butson MJ, Yu P, Metcalfe P (1998) Measurement of off-axis and peripheral skin dose using radiochromic film. Phys Med Biol 43(9):2647–2650
Butson M, Yu P, Metcalfe P (1998) Effects of readout light sources and ambient light on radiochromic film. Phys Med Biol 43:2407–2412
Butson MJ, Yu PKN, Metcalfe PE (1999) Extrapolated surface dose measurements with radiochromic film. Med Phys 26:485–488
Bouchard H, Lacroix F, Beaudoin G, Carrier JF, Kawrakow I (2009) On the characterization and uncertainty analysis of radiochromic film dosimetry. Med Phys 36(6):1931–1946
Ferreira BC, Lopes MC, Capela M (2009) Evaluation of an Epson flatbed scanner to read Gafchromic EBT films for radiation dosimetry. Phys Med Biol 54(4):1073–1085
Paelinck L, De Neve W, De Wagter C (2007) Precautions and strategies in using a commercial flatbed scanner for radiochromic film dosimetry. Phys Med Biol 52(1):231–242
Menegotti L, Delana A, Martignano A (2008) Radiochromic film dosimetry with flatbed scanners: a fast and accurate method for dose calibration and uniformity correction with single film exposure. Med Phys 35(7):3078–3085
Saur S, Frengen J (2008) GafChromic EBT film dosimetry with flatbed CCD scanner: a novel background correction method and full dose uncertainty analysis. Med Phys 35(7):3094–3101
Kalef-Ezra J, Karava K (2008) Radiochromic film dosimetry: reflection vs transmission scanning. Med Phys 35(6):2308–2311
Butson MJ, Cheung T, Yu PK (2009) Evaluation of the magnitude of EBT Gafchromic film polarization effects. Australas Phys Eng Sci Med 32(1):21–25
Butson MJ, Cheung T, Yu PKN (2006) Scanning orientation effects on EBT Gafchromic film dosimetry. Australas Phys Eng Sci Med 29:281–284
Cheung T, Butson MJ, Yu PK (2005) Post-irradiation colouration of Gafchromic EBT radiochromic film. Phys Med Biol 50(20):N281–N285
Yu PK, Butson M, Cheung T (2006) Does mechanical pressure on radiochromic film affect optical absorption and dosimetry? Australas Phys Eng Sci Med 29(3):285–287