著者
足立 宏美 稲越 英機 早川 岳英 井上 富夫 笠原 敏文 五十嵐 智 早川 英樹 棚邊 哲史
出版者
公益社団法人日本放射線技術学会
雑誌
日本放射線技術學會雜誌 (ISSN:03694305)
巻号頁・発行日
vol.64, no.3, pp.306-315, 2008-03-20
被引用文献数
2 2

To estimate the collimator scatter factor, <i>S</i><sub>c</sub> of small field sizes in which a mini-phantom cannot be fully included at the nominal treatment distance (NTD=100 cm), we measured the in-air output of 4 MV and 10 MV X-rays of a Varian's Clinac 2100 C/D using a mini-phantom at NTD and at a long source-to-chamber distance (SCD=200 cm) with field-size defined at the isocenter down to 4.6×4.6cm<sup>2</sup> and 2.3×2.3cm<sup>2</sup>, respectively. We then compared the fitted curve to the NTD dataset by a cumulative exponential distribution model with that by a cumulative Gaussian distribution (error function) model containing a zero-field extrapolated term derived from the long SCD dataset. The results showed that the zero-field extensions of two fitted curves coincided for a 4 MV X-ray, but a large discrepancy was seen between them for a 10 MV X-ray. Therefore, the <i>S</i><sub>c</sub> of small field sizes not measurable using a mini-phantom at the NTD can be well estimated by applying the cumulative exponential model to the NTD dataset in the case of a 4 MV X-ray beam filtrated with a cone-shaped flattener. However, to estimate the <i>S</i><sub>c</sub> of such small field sizes in the case of a 10 MV X-ray beam filtrated with a bell-shaped flattener, we consider it preferable to also measure in-air output at a long SCD and to apply the cumulative Gaussian model as described here.

言及状況

外部データベース (DOI)

Twitter (1 users, 1 posts, 0 favorites)

こんな論文どうですか? 遠距離法と2つの飽和モデルによる小照射野のコリメータ散乱係数S_cの推定(足立 宏美ほか),2008 http://t.co/fyDlaWsi

収集済み URL リスト