x-rays · i fundamentals of x-rays i generation of x-rays i detection of x-rays i imaging and...
TRANSCRIPT
![Page 1: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/1.jpg)
X-Rays
Jan Kybic
2005–2014
![Page 2: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/2.jpg)
Overview
I Fundamentals of X-rays
I Generation of X-rays
I Detection of X-rays
I Imaging and diagnostic methods
![Page 3: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/3.jpg)
Invention
1895, W. Rontgen B. Rontgen hand modern hand
![Page 4: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/4.jpg)
Electromagnetic spectrum
![Page 5: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/5.jpg)
Particles and waves
I reflection, scattering, refraction, diffraction
I photons with energy E = hf ,λ = 1 nm ≈ 1.2 · 103 eV = 1.2 keV
I ionizing radiation (above 1 eV)
![Page 6: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/6.jpg)
Chest X-rays radiography machine
![Page 7: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/7.jpg)
Chest X-ray
![Page 8: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/8.jpg)
X-ray scanner
![Page 9: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/9.jpg)
X-ray source
I 15 ∼ 150 kV, rectified ACI 50 ∼ 400 mA anode currentI tungsten wire (200µm) cathode, heated to ∼ 2200◦CI anode rotates at 3000 rpmI molybdenum or thungsten-rhenium anodeI thermoionic emission
![Page 10: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/10.jpg)
Beam focusing
I Focal spot size 0.3 mm ∼ 1.2 mm
![Page 11: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/11.jpg)
Penumbra
I geometric unsharpness
I small focal spot
I large distance
![Page 12: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/12.jpg)
X-ray tube
![Page 13: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/13.jpg)
X-ray parameters
Intensity: [W /m2]: ∝ U2ISpectrum: (150 kV)
I Bremsstrahlung
I Characteristic radiation
I Filter low-energy rays that would not penetrate the patient —Al sheets. (skin dose reduced 80×)
![Page 14: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/14.jpg)
Interaction between X-rays and matter
I Coherent scattering
I Photoelectric effect
I Compton scattering
I (Pair production)
I (Photodisintegration)
![Page 15: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/15.jpg)
Coherent (Rayleigh) scattering
I Photon −→ photon
I Low-energy radiation
I Probability ∝ Z8/3eff /E 2.
I Zeff - effective atomic numberI muscle Zeff ≈ 7.4, bone Zeff ≈ 20
I About 5 ∼ 10 % of tissue interactions
![Page 16: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/16.jpg)
Photoelectric effect
I High-energy radiationI Photon −→ characteristic radiation, photo-electron / Auger
electron, positive ionI −→ ionizationI Desirable, X-ray photon completely absorbed
![Page 17: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/17.jpg)
Photoelectric interaction wrt E
I K -edgeI Probability ∝ Z 3
eff/E3 (above K -edge)
I Excellent contrast bone/tissue at low E
![Page 18: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/18.jpg)
Compton scattering
Escatt =Einc
1 + Eincmec2
(1− cos θ
)I photon −→ photon + electron, ionization
I most frequent in X-ray imaging, especially for high Einc
I independent to atomic number −→ small contrast
I background noise, health hazard
![Page 19: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/19.jpg)
Effects of Compton scattering
![Page 20: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/20.jpg)
Attenuation
dI = −nσIdxIx = I0e
−µx
µ — linear attenuation coefficientHalf-value layer ≈ 0.693/µ
Mass attenuation coefficient µ/ρ
![Page 21: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/21.jpg)
Attenuation factors wrt E
µ = µphotoel + µCompton + µcoherent
![Page 22: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/22.jpg)
Attenuation wrt E (2)
![Page 23: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/23.jpg)
Beam restrictor / Collimator
![Page 24: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/24.jpg)
Beam restrictor / Collimator (2)
![Page 25: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/25.jpg)
Antiscatter grid
Bucky factor = efficiency
![Page 26: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/26.jpg)
Intensifier screen
I 50× sensitivity increase
I thickness; trade-off resolution/sensitivity
I Gd — green, La – blue
I efficiency 20 %
![Page 27: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/27.jpg)
FilmI monochromatic (sensitive to blue), ortochromatic (sens. to
green)I double emulsion (10µm), silver bromide in gelatinI blackening, optical density (OD) log10(Ii/It)I contrast γ = OD2−OD1
log10 E2−log10 E1, slope of the linear region
I latitude (dynamic range), range of useful exposure valuesI grain size sensitivity/resolution trade-offI mixed-particle size −→ high contrastI automatic exposure control, ionization chamber
![Page 28: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/28.jpg)
Digital Sensors
I Computed radiography (CR)I Phosphor-based storage plateI chemical storage (oxidation of Eu)I laser scanning, light erasure
I Digital radiography (DR)I flat-panel detectors (FPD)I thin-film transistor (TFT) arrayI CsI scintillator −→ photo-diode/transistorI 41× 41 cm, 2048× 2048 pixelsI better dynamic range, quantum efficiency, and latitude wrt film
I Charge coupled device (CCD)I Phosphor screen, fiber-optic cables, CCD sensorI good sensitivity, low noise
![Page 29: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/29.jpg)
Digital Sensors
I Computed radiography (CR)I Phosphor-based storage plateI chemical storage (oxidation of Eu)I laser scanning, light erasure
I Digital radiography (DR)I flat-panel detectors (FPD)I thin-film transistor (TFT) arrayI CsI scintillator −→ photo-diode/transistorI 41× 41 cm, 2048× 2048 pixelsI better dynamic range, quantum efficiency, and latitude wrt film
I Charge coupled device (CCD)I Phosphor screen, fiber-optic cables, CCD sensorI good sensitivity, low noise
![Page 30: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/30.jpg)
Digital Sensors
I Computed radiography (CR)I Phosphor-based storage plateI chemical storage (oxidation of Eu)I laser scanning, light erasure
I Digital radiography (DR)I flat-panel detectors (FPD)I thin-film transistor (TFT) arrayI CsI scintillator −→ photo-diode/transistorI 41× 41 cm, 2048× 2048 pixelsI better dynamic range, quantum efficiency, and latitude wrt film
I Charge coupled device (CCD)I Phosphor screen, fiber-optic cables, CCD sensorI good sensitivity, low noise
![Page 31: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/31.jpg)
X-ray image characteristics
I Signal-to-noise ratio (SNR)I Quantum mottle, source variation, Poisson distribution,I SNR ∝
√N, N — intensity / photons per area
I exposure time and current, SNR ∝√TI
I higher U −→ more high-energy rays −→ moreincident photons −→ better SNR
I X-ray filtering −→ smaller SNRI patient size, antiscatter grid, intensifying screen, film
I Spatial resolution
I Contrast-to-noise ratio
![Page 32: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/32.jpg)
X-ray image characteristics
I Signal-to-noise ratio (SNR)I Spatial resolution
I point spread function (PSF), line spread function (LSF), edgespread function (ESF), modulation transfer function (MTF)
I thickness of the intensifier screenI speed of the X-ray filmI geometric unsharpnessI magnification factor (patient −→ film). Place patient as
close as possible.
I Contrast-to-noise ratio
![Page 33: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/33.jpg)
X-ray image characteristics
I Signal-to-noise ratio (SNR)
I Spatial resolutionI Contrast-to-noise ratio
I CNR = |SA−SB |σN
= |SNRA − SNRB |
![Page 34: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/34.jpg)
X-ray contrast agentsI barium sulfate, gastrointestinal tract
![Page 35: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/35.jpg)
X-ray angiography
I Stenosis, clotting of arteriesI Iodine-based contrast agentI Time series
I Excellent resolution (100µm)I Digital subtraction angiography (DSA)I Registration needed
![Page 36: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/36.jpg)
X-ray angiography
I Stenosis, clotting of arteries
I Iodine-based contrast agent
I Time series
I Excellent resolution (100µm)
I Digital subtraction angiography (DSA)
I Registration needed
![Page 37: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/37.jpg)
DSA example
![Page 38: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/38.jpg)
Fluoroscopy / Intra-operative imaging
I Now a FPD/CCD instead of the fluorescent screen.
![Page 39: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/39.jpg)
Fluoroscopy example
![Page 40: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/40.jpg)
Dual-Energy Imaging
I Two exposures
I Two detectors
I Beam hardening
![Page 41: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/41.jpg)
Dual-energy example
![Page 42: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/42.jpg)
Mamography
I low U (25 ∼ 30 kV), filter high-energy rays
I digital mamography, CCD sensor (1024× 1024 pixels)
![Page 43: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/43.jpg)
X-ray Advantages / disadvantages
I AdvantagesI Widely used and availableI Experts availableI High-spatial resolutionI Excelent imaging of hard tissues (bones)
I DisadvantagesI Radiation exposureI Difficulty in imaging soft-tissuesI 2D projection, hidden parts
![Page 44: X-Rays · I Fundamentals of X-rays I Generation of X-rays I Detection of X-rays I Imaging and diagnostic methods. Invention ... X-ray source I 15 ˘150kV, recti ed AC I 50 ˘400mA](https://reader034.vdocuments.mx/reader034/viewer/2022042515/5fa4358da6cad6461c76ed02/html5/thumbnails/44.jpg)
New trends
I FPD/CCD sensors replace film
I higher sensitivity, faster exposure, lower dose
I dynamic imaging
I CT