熊本大学学術リポジトリ Kumamoto University Repositor Title 腹部領域の C-arm CT におけるスキャンパラメータと画質 Author(s) 永末, 望 ; 船間, 芳憲 ; 鬼木, 里佳 ; 瀬川, 敦史 ; 岩竹, 聡 ; 川内野, 友彦 ; 上谷, 雅孝

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1 熊本大学学術リポジトリ Kumamoto University Repositor Title 腹部領域の C-arm CT におけるスキャンパラメータと画質 Author(s) 永末, 望 ; 船間, 芳憲 ; 鬼木, 里佳 ; 瀬川, 敦史 ; 岩竹, 聡 ; 川内野, 友彦 ; 上谷, 雅孝 Citation 日本放射線技術学会雑誌, 65(6): Issue date Type URL Right Journal Article (c) 2009 Japanese Society of Radiol Technology

2 C-arm CT 765 ノート論文受付 2009 年 1 月 16 日論文受理 2009 年 4 月 8 日 Code No. 251 腹部領域の C-arm CT におけるスキャンパラメータと画質永末望船間芳憲 1) 鬼木里佳 2) 2) 瀬川敦史岩竹聡 2) 川内野友彦 2) 3) 上谷雅孝熊本大学医学部附属病院医療技術部 1) 熊本大学医学部保健学科放射線技術科学専攻 2) 長崎大学医学部歯学部附属病院医療技術部 3) 長崎大学大学院医歯薬学総合研究科放射線生命科学講座放射線診断治療学緒言 computed tomography during arterial portography CTAP CT during hepatic arteriography CTHA CT digital subtraction angiography DSA 1 4 Wallace interventional radiology IVR C-arm CT 5 DSA 6, 7 IVR CT X C-arm CT X X 8 C-arm CT 1 Combinations of Scan Parameters and Image Quality at C-arm CT for Abdominal Imaging Nozomu Nagasue, Yoshinori Funama, 1) Rika Oniki, 2) Atsushi Segawa, 2) Satoshi Iwatake, 2) Tomohiko Kawachino, 2) and Masataka Uetani 3) Department of Radiology, Kumamoto University Hospital 1)Department of Radiological Sciences, School of Health Sciences, Kumamoto University 2)Department of Radiology, Nagasaki University Hospital 3)Department of Radiology and Radiation Biology, Nagasaki University Graduate School of Biomedical Sciences Received January 16, 2009; Revision accepted April 8, 2009; Code No. 251 Summary We measured the contrast-to-noise ratio CNR and evaluated low-contrast images and streak artifacts to optimize abdominal C-arm CT imaging, and we investigated the view number, acquisition matrix, and pixel depth. To measure CNR, we filled inch cavities in an American Association of Physicists in Medicine AAPM CT performance phantom with a sodium chloride solution. Five radiological technologists visually evaluated the noise, signal conspicuity at low- and high-signal density, and the overall image quality using paired comparisons based on Thurstone s law. In a given acquisition matrix, the total view number had the greatest effect on the image noise, artifacts, and signal detectability on C-arm CT images. For a given incident dose per view on the flat-panel detector FPD, fewer images with noise and streak artifacts resulted when a larger view number was selected. Key words: C-arm CT, scan protocol, image quality, radiation dose, abdominal imaging

3 766 Table 1 Protocol for appropriate C-arm CT in abdominal imaging Protocol A Protocol B Protocol C Scan time sec View angle deg View number Pixel depth bits Frame rate f/s Acquisition matrix flat-panel detector FPD C-arm CT contrast-to-noise ratio CNR 1 1. 材料および方法 FPD SIEMENS AXIOM Artis dba 0.154mm C-arm CT field of view FOV 22cm sec 5 CT sec 20sec C-arm CTTable 1 3 A B C Fig. 1 Fig. 2 VICTOREEN American association of physicists in medicine AAPM CT Phantom Laboratory Catphan 2 10, 11 AAPM CT Catphan 1 21lp/cm A B C mm FPD X 0.54eGy 15cm 30f/s 60f/s X kV kV 1-1 X 15cm PTW Farmer 0.6cc 5cm X contrast-to-noise ratio CNR AAPM 6 z C-arm CT 12mm S.D. Fig SIEMENS CT volume zoom 4 CT C-arm CT 80kV CT HU CT 65 6

bottom of the tank that includes two rows of cavities from 1 to 0.

The phantom containing high resolution test gauges of 1 through 21

The diameter and length along the Z-axis of the acrylic annulus were 32.

4 C-arm CT 767 Fig. 1 AAPM CT performance phantom a contrast test object is adhered to the bottom of the tank that includes two rows of cavities from 1 to inch in diameter. Fig. 2 Catphan phantom. The phantom containing high resolution test gauges of 1 through 21 linepairs per centimeter was cast into a uniform material. The diameter and length along the Z-axis of the acrylic annulus were 32.0 cm and 10.0 cm, respectively. Fig. 3 Method of measurement for contrast-to-noise ratio CNR. Example image shows mean CNR at 3.0 and 5.0 calculated from 3 digital values on signal- and base-parts

768 A B C Fig. 4 Low-contrast image in each protocol at A, B, and C. Contr ast f or low-contr a s t module was 40 and -30 HU at right- and left side of image, respectively.

5 768 A B C Fig. 4 Low-contrast image in each protocol at A, B, and C. Contr ast f or low-contr a s t module was 40 and -30 HU at right- and left side of image, respectively. CT CNR CNR= digital value signal digital value base / SD base Fig. 4 AAPM CT CT +40 hounsfield unit HU 30HU AB AC BC Catphan Catphan z FPD 13 3 z z Steel-Dwass 結果 2-1 X 1 Table 2 A 65 6

6 C-arm CT 769 Table 2 Radiation dose per view and standard deviation S.D. in each protocol Radiation dose/view mgy S.D. Protocol A Protocol B Protocol C Fig. 5 Relationship between image noise and concentration of sodium chloride solution in each protocol A, B, and C. Error bar shows one standard deviation 1 S.D.. Fig. 6 Relationship between contrastto-noise ratio and concentration of sodium chloride solution in each protocol at A, B, and C. Error bar shows one standard deviation 1 S.D mGy 1.99mGy/view B 850.6mGy 2.03mGy/view 1 A C 720.5mGy 2.62mGy/view 1 A B CNR Fig. 5 C A B CNR Fig. 6 CNR B

770 2-3 Fig. 7 CT +40HU A B 1.97 C 2.24 A B C BC CT 30HU C A 2.64 B 3.54 C A 1.37 B 3.78 1-3 Fig. 7 Image evaluation of low-contrast material using paired comparisons based on Thurstone s law.

7 Fig. 7 CT +40HU A B 1.97 C 2.24 A B C BC CT 30HU C A 2.64 B 3.54 C A 1.37 B Fig. 7 Image evaluation of low-contrast material using paired comparisons based on Thurstone s law. 2-4 Fig. 8 A B C B A C AC 3. 考察 C-arm CT X 1 1 P= s/f mas kv V P s/f 1 mas kv V 1 s/f mas kvp V 60f/s 1/60sec 30f/s 1/30sec 1/60sec1/30sec Fig. 8 Result of streak artifact for three protocols of A, B, and C. Error bar shows one standard deviation 1 S.D X 32 A C B FPD X CNR B 65 6

8 C-arm CT 771 CNR A C +40HU A C +40HU CNR Fig. 7 C C A +40HU A C B B C-arm CT AC CNR C-arm CT CNR C-arm CT 10HU 15 C-arm CT 1 ` C 10sec A B CNR B 8sec 419 CNR B A 6sec AAPM CT X 2 CT CT C-arm CT80kV AAPM CT CT X C-arm CT CT X CT 4. 結論 C-arm CT

9 772 C-arm CT CNR 1 B 8sec 419 A 6sec 229 CNR 参考文献 Hirai T, Korogi Y, Ono K, et al. Intraarterial chemotherapy or chemoembolization for locally advanced and/or recurrent hepatic tumors: evaluation of the feeding artery with an interventional CT system. Cardiovasc Intervent Radiol 2001; 24 3 : Kanematsu M, Hoshi H, Imaeda T, et al. Detection and characterization of hepatic tumors: value of combined helical CT hepatic arteriography and CT during arterial portography. AJR Am J Roentgenol 1997; : Hirai T, Korogi Y, Ono K, et al. Preoperative embolization for meningeal tumors: evaluation of vascular supply with angio-ct. AJNR Am J Neuroradiol 2004; 25 1 : Fahrig R, Dixon R, Payne T, et al. Dose and image quality for a cone-beam C-arm CT system. Med phys 2006; : Wallace MJ, Murthry R, Kamat PP, et al. Impact of C-arm CT on hepatic arterial interventions for hepatic malignancies. J Vasc Interv Radiol 2007; : Wallace MJ, Kuo MD, Glaiberman C, et al. Three-dimensional C-arm cone-beam CT: applications in the interventional suite. J Vasc Interv Radiol 2008; 19 6 : Endo M, Tsunoo T, Nakamori N, et al. Effect of scattered radiation on image noise in cone beam CT. Med Phys 2001; 28 4 : Feldkamp LA, Davis LC, Kress JW. Practical cone-beam algorithm. J Opt Soc Am A 1984; 1 6 : Verdun FR, Denys A, Valley JF, et al. Detection of lowcontrast objects: experimental comparison of single- and multi-detector row CT with a phantom. Radiology 2002; : Gupta AK, Nelson RC, Johnson GA, et al. Optimization of eight-element multi-detector row helical CT technology for evaluation of the abdomen. Radiology 2003; : Grass M, Köhler T, Proksa R. 3D cone-beam CT reconstruction for circular trajectories. Phys Med Biol 2000; 45 2 : DynaCT Innervision 図表の説明 Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 AAPM CT Catphan Contrast-to-noise ratio CNR A B C A B C A B C CNR A B C Table 1 C-arm CT Table

CT 1201 CT 5 CT CT CT CT CT 1. 方法 CT 1-1 CT CT Fig. 1 CT X 5 μm 100 kv 100 μa X L μm CsI CMOS Fig. 1 Educational cone-beam CT system.

CT 1201 CT 5 CT CT CT CT CT 1. 方法 CT 1-1 CT CT Fig. 1 CT X 5 μm 100 kv 100 μa X L μm CsI CMOS Fig. 1 Educational cone-beam CT system. 1200 ノート論文受付 2011 年 5 月 2 日論文受理 2011 年 7 月 21 日 Code Nos. 131 251 532 1070 放射線技師教育用コーンビーム CT システムの開発寺本篤司 1) 尾崎香帆 2) 宮下真梨子 3) 4) 大野智之津坂昌利 5) 藤田広志 6) 1) 小原健 1) 藤田保健衛生大学医療科学部放射線学科 2) 東名古屋画像診断クリニック 3) セントラル病院