270 likes | 390 Views
Study of Phase-Dispersive X-Ray Imaging. Tomomi Ohgaki and Ichita Endo (Hiroshima Univ.). Study of Phase-Dispersive X-Ray Imaging. X-Ray Imaging Equipments. Absorption Contrast Method ( Usual ) Phase Contrast Method. For Medical application. Early diagnoses of breast cancer
E N D
Study of Phase-Dispersive X-Ray Imaging Tomomi Ohgaki and Ichita Endo (Hiroshima Univ.)
Study of Phase-Dispersive X-Ray Imaging X-Ray Imaging Equipments • Absorption Contrast Method (Usual) • Phase Contrast Method For Medical application Early diagnoses of breast cancer Imaging for living soft tissues Plane wave passing through the object
Cross Section of X-Ray Absorption and Phase Shift Phase Shift Cross Section (cm2) X-ray Energy 8.3 keV 13.5keV 24.8keV 62.0keV Absorption Phase Contrast Atomic Number Phase shift of light elements 1000 times higher than absorption Radiation dose by phase contrast imaging can be reduced.
Setup for X-Ray Phase-Dispersive Measurements X-Ray Tube Characteristic X-Ray 60~70 keV Target W,Re,Au Monochrometor Silicon single crystal Asymmetric Bragg Diffraction Crystal Analyzer Silicon single crystal Higher order diffraction Maximum contrast by rotating Crystal analyzer X-Ray Detectors Imaging plateseveral 10mm Emulsion several mm X-Ray CCD several 10mm Transmission, Reflection X-Ray measurements
Reflection and Transmission Intensities W Ka-Line (59.3keV) Crystal analyzer Si(422) thickness 560mm Rotating crystal analyzer a~rotation angle No object case
Transmission Intensity W Ka-Line (59.3keV) Crystal analyzer Si(422) thickness 560mm Object (Prism, base 2mm, base angle 45degree) df/dx
Reflection Intensity W Ka-Line (59.3keV) Crystal analyzer Si(422) thickness 560mm Object (Prism, base 2mm, base angle 45degree)
Reflection and Transmission Intensities W Ka-Line (59.3keV) Crystal analyzer Si(422) thickness 560mm Object (Prism, base 2mm, base angle 45degree) Dq=-4.8x10-7rad (a=-0.70)
Samples of Phase Contrast Method Veins of leaf (S.Wilkins et al., 1998) Arteries of mouse (V.N.Ingal et al.,1998)
Approach to Venture Business Medical application, Electronics, Aerospace, Food industries • Medical diagnoses … breast cancer, malignant tumors • Search for impurity objects in Foods • Study of Biology • Search of oil …fluid mechanics • Investigation of object of art or craft object • Investigation of new materials like ceramics or fiber
Simulation by Dynamical Diffraction Theory X-Ray • Disagreement between analytical • formulas and experimental results • where df/dx is large changeable. Crystal surface Solve Takagi-Taupin equations using Simulation. Reflection X-Ray Transmission X-Ray
Simulation code CPRI Purpose:Calculate Phase Radiological Imaging • X-ray tube or SOR light: Target size, current, voltage • Slit: Transfer matrix • Monochromator: Asymmetric Bragg diffraction • Object: Linear absorption coefficient, refractive index • Crystal analyzer: Takagi-Taupin eqs. • Detector: Detection area, Detection efficiency
Intensity of one photon incidence Incident X-Ray Crystal surface Si Crystal Crystal surface
X-Ray Tube X-Ray Tube 22.5mA 55kV Target Mo
Imaging Plate Reader Rigaku R-AXIS-D53
Prototype experiments Laue case Ge crystal(220) thickness200mm qB=10.2° Asymmetric Bragg Diffraction Ge crystal (115) qB=19.0° qB-a=3.2° b=0.0983 Mo Ka1-line l=0.709260Å w=17.480 keV Polypropylene r=0.95g/cm3
Rocking curve from crystal analyzer Laue case w=295mrad w=329mrad Ge (220) w=27.4mrad qx=820mrad qy=13mrad
Transmission Image of Polypropylene q-qB=-160 mrad q-qB=0 mrad q-qB=+160 mrad
Rocking curve from crystal analyzer Bragg case w=235mrad Si (220) w=10.9mrad
Reflection Image of Polypropylene q-qB=0 mrad
Summary • We have done the prototype experiments for PDI. • We have made the simulation code for PDI. • Now Hiroshima group will study PDI with Betatron. 「位相コントラストX線撮像装置」大垣智巳、遠藤一太、特願2001-203219 (July 11, 2001)"Simulation code for phase radiological imaging using dynamical theory” T.Ohgaki and I.Endo
REFER Hiroshima Univ. got RF cavity Beam life time is 4min.