著者

福永 正明 大西 英雄 松友 紀和 山本 浩之

出版者

公益社団法人 日本放射線技術学会

雑誌

日本放射線技術学会雑誌 (ISSN:03694305)

巻号頁・発行日

vol.72, no.6, pp.489-495, 2016 (Released:2016-06-20)

参考文献数

12

被引用文献数

1

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Purpose: The purpose of this study was to evaluate the effects of target diameter and display-field of view (D-FOV) in modulation transfer function (MTF) by circular edge strategy using the computed tomography (CT) image measurement program “CTmeasure”. Methods: We calculated the MTF (MTFedge) using the circular edge strategy applied to cylindrical phantom (200 mmφ) that inserted with cylinders have 10, 20, 30, and 40 mm diameters. The phantom images were reconstructed using filtered back projection method varied with D-FOV (240, 320, 400, and 500 mm). The study compared both MTFedge and MTFwire at MTF50% and MTF10% for target diameter and D-FOV, respectively. Results: The MTFedge by the different of target diameter indicated in rough compatibility. However, MTFedge of D-FOV diameters (320, 400, and 500 mm) decreased in the high frequency range. Conclusions: The circular edge strategy for MTF depended on the D-FOV, however, it was little dependent on target diameter using the CT image measurement program “CTmeasure”.

著者

坪井 邦仁 福永 正明 山本 浩之

出版者

公益社団法人 日本放射線技術学会

雑誌

日本放射線技術学会雑誌 (ISSN:03694305)

巻号頁・発行日

vol.72, no.12, pp.1237-1244, 2016 (Released:2016-12-20)

参考文献数

17

被引用文献数

3 1

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Purpose: The purpose of this study was to investigate the effects of the metal artifact reduction using single energy metal artifact reduction (SEMAR) with a prosthetic hip joint in different field of view (FOV). Methods: A prosthetic hip joint was arranged at the center of the phantom. The phantom images were scanned by changing calibrated-FOV (C-FOV) of 240, 320, 400, and 500 mm. Those images were reconstructed by changing the display-FOV (D-FOV) of 120, 180, 240, and 320 mm. The metal artifact reduction with the SEMAR was evaluated by calculating the artifact index (AI) and its decrease ratio. Results: The AI of C-FOV (500 mm) and D-FOV (120, 180, 240, or 320 mm) were 15.8, 15.8, 15.7, and 14.4 with SEMAR. For changed C-FOV, the AI of C-FOV (240 mm) was significantly higher than any other C-FOVs. The AI of C-FOV (240 mm) was 29.8–30.0 and that of the other C-FOV were 12.4–15.8 with SEMAR. In addition, the decrease ratio of AI was 52.2–54.1% for C-FOV (240 mm) and 58.9–73.2% for the other C-FOVs. Conclusion: Although the SEMAR decreased the metal artifact, the effect of reducing the metal artifact was affected by C-FOV.