@article{oai:iuhw.repo.nii.ac.jp:00000007,
 issue = {1},
 journal = {国際医療福祉大学紀要, Bulletin of International University of Health and Welfare},
 month = {Aug},
 note = {本研究では,空間解像度とコントラストの総合的な視覚評価ができる新しいX線CT用バーガーファントム(BP)を提案し,その基本特性を明らかにした。新しいBPは,直径200mm,厚さ20mmの円形のアクリル板に直径1mm〜10mmの8種類の孔を開け,そこにアクリル板とCT値が異なる種々の濃度の塩化ナトリウム(NaCl)水溶液を封入したものである。NaCl水溶液とアクリルのCT値差を5〜110まで11種類に設定した。実験的にNaCl水溶液の濃度とCT値の関係式を求め,対応する濃度のNaCl水溶液を封入してBPを自作した。このBPのNaCl水溶液の設定CT値と実測CT値は画像ノイズの範囲で一致した。これにより,一個のBPで8種類の孔径,11種類のコントラストをもつ画像が得られることを確認した。また,7人の観察者が視覚評価を行いC-Dダイアグラムを作成し線量の異なるX線CT画像の比較を行うことができた。しかし,特定の孔の配列が先入観を与えることや主観的な判定基準のため観察者による変動が大きく,ファントム形状および視覚評価法の検討が今後の課題である。, A new Burger Phantom for X-ray CT(BP)has been proposed to visually evaluate both spatial resolution and contrast, and its characteristics are investigated. The new BP is made of an acrylic disk with 8 different hole diameters, from 1 to 10mm, filled with 11 different concentrations of NaCl solution. The diameter of the disk is 200mm and its thickness 20mm. The differences between the CT number of the NaCl solution and the acrylic were set from 5 to110. The relationship between the concentrations of the NaCl solution and the CT numbers was obtained experimentally and each hole was filled with NaCl solution corresponding to each CT number. The difference between the predetermined CT number and the measured CT number of the NaCl solution was within the range of image noise. It was confirmed that an image of holes with 8 different diameters and 11 different contrasts was obtained by using only one BP. The C-D diagram has been generated by using images of one BP at the various X-ray doses and evaluated by 7 observers. However, the data fluctuate between observers because of each observer's preconception of the hole arrangement and the subjective conviction criterion. Therefore, improvement of the BP construction and visual evaluation method is needed.},
 pages = {14--23},
 title = {新しいX線CT用バーガーファントムの提案},
 volume = {16},
 year = {2011}
}