GafChromic線量測定における光学フィルタを用いた感度特性に関する検討

• Published in: 日本放射線技術学会雑誌 Vol. 63; no. 11; pp. 1253 - 1256
• Main Authors: 中田, 学, 岡田, 孝, 宮部, 結城, 高倉, 亨, 藤本, 隆広, 矢野, 慎輔, 越田, 吉郎, 加茂前, 健, 菊池, 雄三
• Format: Journal Article
• Language: Japanese
• Published: 公益社団法人 日本放射線技術学会 2007
• Subjects: band-pass filter; film dosimetry; GafChromic; IMRT; radiotherapy
• ISSN: 0369-4305; 1881-4883
• DOI: 10.6009/jjrt.63.1253

GafChromic EBT film (GC-EBT) is lower in sensitivity than ready-pack film. The purpose of this study was to increase GC-EBT sensitivity by using band-pass filters and a polarized light filter. The filters were inserted between the GC-EBT and the scanner bed and digitized. We evaluated the sensitivity characteristic, amount of noise, and the dose corresponding to noise. When only the band-pass filter was inserted, a filter of transmission wavelength peak at 600 nm showed the maximum sensitivity. When a filter of 600 nm in transmission peak at wavelength was combined with a polarized light filter, sensitivity improved. There was no increase in the amount of noise according to the type of filter. The dose corresponding to noise increased as the quantity of light after passing through the filter decreased. When a suitable band-pass filter for the absorption peak of GC-EBT was used, it was suggested to be able to improve sensitivity without increasing noise.