カオス理論を用ぃたX線デイ
Contents
1. Contrast Detail C D 2 C D 2 1 CDRAD 1 Flat Panel Detector GE Healthcare Definium8000 X2. C D 3 2 Fig 2 Signal image 100 a 2 J Le tg I8 Pixel Value ed 20 40 60 Position Fig 3 Profile of signal image 4100 F f 1 NN 3905 Too Too Fig 4 Return map 2 C D 3
3. 1 Computed Radiography CR Flat Panel Detector FPD X 1 461 8673 1 1 20 e mail imai met nagoya u ac jp 2 TAUR X
4. mAs X gt 0 C D C D X mAs 3 1 mAs
5. ee X MARIOS SL REID X MRA MTF NPS Aliasing Shift invariance
6. 1X64 pixel 4 3 7 G 2 PU PG Dlog PU DG Pi 7 C D 4 41 5 mAs mAs mAs
7. C D QF X 20 C x RR 1 R Shaw The Dripping Faucet as A model Chaotic System Aerial Press 1984 2 E Ott Strange attractors and chantic motions of dynamical systems Rev Mod Phys Vol 53 No 4 p654 1981 3 Alt 2004 4 1979 5 C D RAD The method entropy estimation in digital radiography with chaotic theory Takanori Ishiyama Kuniharu Imai Mitsuru Ikeda Yukihiro Enchi 1 Department of Radiological Technology Nagoya University School of Health Sciences
8. Tze ey lt Tube Voltage 110kVp 9 ent bit Vv Lyapnoy Expon Lyapnov Exponent bit ci 3 mAs Fig S Relationship between Lyapnov exponent and mAs Tube Voltage 110 kVp Lyapunov Exponent bit 0 25 03 IQF Fig 6 Relationship between Lyapnov exponent and IQF IQF 6 IQF LOR IQF C D IQF Tube Voltage 110 kVp 25 mAs 4 0 mAs Contrast 8 0 mm in Equivocation bit a5 i 3 10 Size mm Fig 7 Relationship between equivocation and signal size 42
9. C D 8 4 0 mAs CD Tube Voltage 110 kVp mAs 4 0 mAs Ji 5 lt g agra 8 C D Diagram dos E z 1 fe X Z 3 Go pees Equivocation 0 1 1 4 WN L 4 3 63 i 3 io Contrast mm Fig 8 C D diagram and equivocations Tube Voltage 110 kVp BO OO amp i gt 0 5mAs go Y 1 0mAs m 2 0mAs O 3 2mAs O 4 0mAs i gt 6 Contrast mm Fig 9 Equivocations on detection limits mAs 8
10. 7 8 0 mm mAs 4 0 mAs mAs
11. UTE 9mm PMMA X 110 kVp 180 cm E X ray tube C D phantom pe es FPD 180 cm Fig 1 Experimental apparatus 0 3 mAs 1 0 mAs 1 6 mAs 2 0 mAs 2 5 mAs 3 2 mAs 4 0 mAs C D phantom 2 2 C D C D C D 2 1 C D mAs 2 AHH U7 3 BOBS C D C D Image Quality Figure 7or IQF 2
12. 2 Division of Radiological Technology Osaka University Hospital In this study we have applied a chaotic theory to the evaluation of image quality of digital radiography and devised a new method for evaluating the image quality A commercially available CDRAD phantom was used as a target object The C D images were acquired at various mAs values 0 5 4 0 mAs and 110 kVp with a flat panel detector system Lyapnov exponent and equivocation devised from the chaos theory were employed as physical indices for evaluating the image quality of the C D images Furthermore we performed the C D analysis in which three radiologists participated The digital C D images were characterized by this chaos model The Lyapnov exponents were equivalent to IQF in the C D analysis The equivocation reduced depending on the increase in the image contrast Therefore our devised method was found to be clinically useful Key words Chaotic theory Information theory Lyapnov exponent Equivocation
13. mAs 2b BUT 2bit SBE IIOkV C D 5 X X X
14. 1 i l Dimin mm i 3 31 2 A lim Y log n gt a y x 2 te dx
15. OP5 01 JAMIT2009 Proceedings X gt MTF NPS C D A a ON
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