general introduction- fundamental principles x ray & ct radiology dept. 1st hospi. of peking...
Post on 15-Jan-2016
223 views
TRANSCRIPT
General introduction- fundamental principles
X ray & CT
General introduction- fundamental principles
X ray & CT
Radiology Dept. 1st Hospi. of Peking University
唐光健
Radiology Dept. 1st Hospi. of Peking University
唐光健
Questions to think of with the lecture
What is X ray? What kinds of the features of it are useful or harmful?
What are the two steps of X ray imaging?
How is the grey scale of bone, muscle and air in the X ray film?
What is the main difference between the CT imaging and the image of X ray film?
What are same and what are different between the processes of CT imaging and imaging of X ray projection?
Is the meaning of a CT axial imaging and a section of a body specimen in same location identical?
What is X ray? What kinds of the features of it are useful or harmful?
What are the two steps of X ray imaging?
How is the grey scale of bone, muscle and air in the X ray film?
What is the main difference between the CT imaging and the image of X ray film?
What are same and what are different between the processes of CT imaging and imaging of X ray projection?
Is the meaning of a CT axial imaging and a section of a body specimen in same location identical?
Black box?
Wilhelm C RöntgenWilhelm C Röntgen
Black box?Black box?
Wilhelm C RöntgenWilhelm C Röntgen
Generation and features of X ray
High speeding electrons Anode target sudden slow down
special X ray – sequence spectrum narrow
consecutive X ray – sequence spectrum wide
High speeding electrons Anode target sudden slow down
special X ray – sequence spectrum narrow
consecutive X ray – sequence spectrum wide
X ray X ray
e
e
special X ray – sequence spectrum narrow
consecutive X ray – sequence spectrum wide
special X ray – sequence spectrum narrow
consecutive X ray – sequence spectrum wide
electromagnetic waves -ionizing radiation -wave length of medical use:
0.08 ~ 0.71Å -feature of wave; feature of particle
Features-Effects
electromagnetic waves -ionizing radiation -wave length of medical use:
0.08 ~ 0.71Å -feature of wave; feature of particle
Features-Effects
Physical effect
Chemical effect
Biotic effect
Physical effect
Chemical effect
Biotic effect
Generation and features of X ray
electromagnetic waves -ionizing radiation -wave length of medical use:
0.08 ~ 0.71Å -feature of wave; feature of particle
Features-Effects
electromagnetic waves -ionizing radiation -wave length of medical use:
0.08 ~ 0.71Å -feature of wave; feature of particle
Features-Effects
Physical effect
Chemical effect
Biotic effect
Physical effect
Chemical effect
Biotic effect
Generation and features of X ray
Penetrability Fluorescent effect Thermal effect Ionizing effect interference , diffraction, reflection, refraction
Penetrability Fluorescent effect Thermal effect Ionizing effect interference , diffraction, reflection, refraction
Features-EffectsFeatures-Effects Physical effect
Chemical effect
Biotic effect
Physical effect
Chemical effect
Biotic effect
Generation and features of X ray
Penetrability Fluorescent effect Thermal effect Ionizing effect interference , diffraction, reflection, refraction
Penetrability Fluorescent effect Thermal effect Ionizing effect interference , diffraction, reflection, refraction
-be able to penetrate ma. of dif. density while attenuated -be able to penetrate ma. of dif. density while attenuated
I0I0 IIµµ
ll
I = I0 · e- µlI = I0 · e- µl
Features-EffectsFeatures-Effects Physical effect
Chemical effect
Biotic effect
Physical effect
Chemical effect
Biotic effect
Generation and features of X ray
Penetrability Fluorescent effect Thermal effect Ionizing effect interference , diffraction, reflection, refraction
Penetrability Fluorescent effect Thermal effect Ionizing effect interference , diffraction, reflection, refraction
-making some compounds fluoresce -Fluoroscopy, image intensifier
-making some compounds fluoresce -Fluoroscopy, image intensifier
Features-EffectsFeatures-Effects Physical effect
Chemical effect
Biotic effect
Physical effect
Chemical effect
Biotic effect
Generation and features of X ray
Penetrability Fluorescent effect Thermal effect Ionizing effect interference , diffraction, reflection, refraction
Penetrability Fluorescent effect Thermal effect Ionizing effect interference , diffraction, reflection, refraction
-making some compounds fluoresce -Fluoroscopy, image intensifier
-making some compounds fluoresce -Fluoroscopy, image intensifier
Features-EffectsFeatures-Effects Physical effect
Chemical effect
Biotic effect
Physical effect
Chemical effect
Biotic effect
Generation and features of X ray
Penetrability Fluorescent effect Thermal effect Ionizing effect interference , diffraction, reflection, refraction
Penetrability Fluorescent effect Thermal effect Ionizing effect interference , diffraction, reflection, refraction
-Subject absorb the energy of X ray ionized ionized voltage -ionizing cell auto-exposure
X ray detector
-Subject absorb the energy of X ray ionized ionized voltage -ionizing cell auto-exposure
X ray detector
Features-EffectsFeatures-Effects Physical effect
Chemical effect
Biotic effect
Physical effect
Chemical effect
Biotic effect
Generation and features of X ray
Penetrability Fluorescent effect Thermal effect Ionizing effect interference , diffraction, reflection, refraction
Penetrability Fluorescent effect Thermal effect Ionizing effect interference , diffraction, reflection, refraction
- penumbra, interferential signal image blued- penumbra, interferential signal image blued
Features-EffectsFeatures-Effects Physical effect
Chemical effect
Biotic effect
Physical effect
Chemical effect
Biotic effect
Generation and features of X ray
sensitization effect
coloration effect
fundament of X ray filming
sensitization effect
coloration effect
fundament of X ray filming
Features-EffectsFeatures-Effects Physical effect
Chemical effect
Biotic effect
Physical effect
Chemical effect
Biotic effect
Generation and features of X ray
radiated tissue cells restrained, damaged, necrosingX ray protection
radiated tissue cells restrained, damaged, necrosingX ray protection
X ray Imaging
X ray penetrate the subject ( body) while attenuated
attenuate signal recorded by the accepting medium
X ray penetrate the subject ( body) while attenuated
attenuate signal recorded by the accepting medium
X ray Imaging
X ray penetrate the subject ( body) while attenuated
attenuate signal recorded by the accepting medium
X ray penetrate the subject ( body) while attenuated
attenuate signal recorded by the accepting medium
I0I0 IIµ1µ1
l1l1
I = I0 · e- µ1l1 · e- µ2l2 · e- µ3l3 · e- µ4l4 I = I0 · e- µ1l1 · e- µ2l2 · e- µ3l3 · e- µ4l4
µ2µ2
l2l2
µ3µ3
l3l3
µ4µ4
l4l4
X ray Imaging
X ray penetrate the subject ( body) while attenuated
attenuate signal recorded by the accepting medium
X ray penetrate the subject ( body) while attenuated
attenuate signal recorded by the accepting medium
getting special distribution o
f different density
overlapping of anterio-post
erior images
getting special distribution o
f different density
overlapping of anterio-post
erior images
X ray Imaging
X ray penetrate the subject ( body) while attenuated
attenuate signal recorded by the accepting medium
X ray penetrate the subject ( body) while attenuated
attenuate signal recorded by the accepting medium
film-silver bromide decomposed positive correlation with
dosage of X raynegative correlation
with degree of attenuation
film-silver bromide decomposed positive correlation with
dosage of X raynegative correlation
with degree of attenuation
flu. screen detectors flu. screen detectors
X ray Imaging
X ray penetrate the subject ( body) while attenuatedattenuate signal recorded by the accepting medium
X ray penetrate the subject ( body) while attenuatedattenuate signal recorded by the accepting medium
grey of spots thickness & density o∽f the mat. in the path way of X ray beam distribution of the spots anatomic ∽ form in the path way of X ray beam difference between the sports - contrastimage
natural contrastartificial contrast
grey of spots thickness & density o∽f the mat. in the path way of X ray beam distribution of the spots anatomic ∽ form in the path way of X ray beam difference between the sports - contrastimage
natural contrastartificial contrast
X ray Imaging
X ray penetrate the subject ( body) while attenuatedattenuate signal recorded by the accepting medium
X ray penetrate the subject ( body) while attenuatedattenuate signal recorded by the accepting medium
grey of spots thickness & density o∽f the mat. in the path way of X ray beam distribution of the spots anatomic ∽ form in the path way of X ray beam difference between the sports - contrastimage
natural contrastartificial contrast
grey of spots thickness & density o∽f the mat. in the path way of X ray beam distribution of the spots anatomic ∽ form in the path way of X ray beam difference between the sports - contrastimage
natural contrastartificial contrast
X ray Imaging
X ray penetrate the subject ( body) while attenuatedattenuate signal recorded by the accepting medium
X ray penetrate the subject ( body) while attenuatedattenuate signal recorded by the accepting medium
grey of spots thickness & density o∽f the mat. in the path way of X ray beam distribution of the spots anatomic ∽ form in the path way of X ray beam difference between the sports - contrastimage
natural contrastartificial contrast
grey of spots thickness & density o∽f the mat. in the path way of X ray beam distribution of the spots anatomic ∽ form in the path way of X ray beam difference between the sports - contrastimage
natural contrastartificial contrast
X ray Imaging
X ray equipment
X ray source X ray tube High voltage generator
X ray imaging devices X ray film / image intensifier / plate detector
X ray mechanical device
exam table frame……
X ray source X ray tube High voltage generator
X ray imaging devices X ray film / image intensifier / plate detector
X ray mechanical device
exam table frame……
X ray tube filament - cathode anode target tube shell
X ray tube filament - cathode anode target tube shell
X ray equipment
X ray equipment
X ray tube filament - cathode anode target tube shell
X ray tube filament - cathode anode target tube shell
Protection from X ray
X ray protectionCancel X ray exam unnecessary
Reduce radiation dosage
Distance from X ray source
Protective device
X ray protectionCancel X ray exam unnecessary
Reduce radiation dosage
Distance from X ray source
Protective device
Principles of imaging diagnosis
familiar with imaging methods and body position
familiar with the normal imaging anatomy and variations
sequential observation
imaging manifestations and relationship with neighboring structures of the lesion
clinical and laboratory materials
understanding the meaning and limitations of the imaging methods
familiar with imaging methods and body position
familiar with the normal imaging anatomy and variations
sequential observation
imaging manifestations and relationship with neighboring structures of the lesion
clinical and laboratory materials
understanding the meaning and limitations of the imaging methods
fundamental principlesof CT
fundamental principlesof CT
CT-Computerized Tomography
real tomography , without any overlapping
CT-Computerized Tomography
real tomography , without any overlapping
fundamental principles of CT
I0 Iµ1µ1
l1l1
I = I0 · e- µ1l1 · e- µ2l2 · e- µ3l3 · e- µ4l4 I = I0 · e- µ1l1 · e- µ2l2 · e- µ3l3 · e- µ4l4
µ2µ2
l2l2
µ3µ3
l3l3
µ4µ4
l4l4
I0 Iµ1µ1
l1l1
I = I0 · e- µ1l1 · e- µ2l2 · e- µ3l3 · e- µ4l4 I = I0 · e- µ1l1 · e- µ2l2 · e- µ3l3 · e- µ4l4
µ2µ2
l2l2
µ3µ3
l3l3
µ4µ4
l4l4
l1 = l1 = l1 = l1 = 1l1 = l1 = l1 = l1 = 1
I = I0 · e- (µ1+ µ2 + µ3 + µ 4) · 1I = I0 · e- (µ1+ µ2 + µ3 + µ 4) · 1
fundamental principles of CT
Godfrey HounsfieldGodfrey Hounsfield First laboratory CT scan
ner 1968First laboratory CT scan
ner 1968
fundamental princ. of CT
fundamental princ. of CT
First clinical head CT scanner
Atkinson Morley‘hosp., London
First clinical head CT scanner
Atkinson Morley‘hosp., London
fundamental principles of CT
measurement measurement
fundamental principles of CT
DAS - data acquisition system -detector -bumper
-integrator -amplifier -A/D converter
DAS - data acquisition system -detector -bumper
-integrator -amplifier -A/D converter
detector detector
fundamental principles of CT
measurement measurement
Reconstruction Reconstruction
fundamental principles of CT
backprojective method Iterative method Factorial method
Fourier methodFilt. backprojective method
backprojective method Iterative method Factorial method
Fourier methodFilt. backprojective method
fundamental principles of CT
Reconstruction Reconstruction
Filt. function(Kernol)
High filt.(bone algorithm)low filt.(soft tissue algorithm)
Filt. function(Kernol)
High filt.(bone algorithm)low filt.(soft tissue algorithm)
fundamental principles of CT
Reconstruction Reconstruction
Filt. function(Kernol)
High filt.(bone algorithm)low filt.(soft tissue algorithm)
Filt. function(Kernol)
High filt.(bone algorithm)low filt.(soft tissue algorithm)
fundamental principles of CT
Reconstruction Reconstruction
[(μobj.- μwater)/μwater]×1000 [(μobj.- μwater)/μwater]×1000
CT value -relative magnitude to watermay be used qualitatively
but not quantitively
CT value -relative magnitude to watermay be used qualitatively
but not quantitively
fundamental principles of CT
Reconstruction Reconstruction
image display image display
fundamental principles of CT
200/30=7HU
muscle 50HU- fat -50HU=100 ~13 grey scale
200/30=7HU
muscle 50HU- fat -50HU=100 ~13 grey scale
1000/30=33HU
muscle 50HU- fat -50HU=100 ~3 gray scale
1000/30=33HU
muscle 50HU- fat -50HU=100 ~3 gray scale
image display image display
ability of identify grey scale
eyes: 24~30 CT: 2000
ability of identify grey scale
eyes: 24~30 CT: 2000
fundamental principles of CT
Voxel and pixel
voxel – 3D, pixel – 2D
CT value of a voxel represent all messages of the elements in the voxel
Voxel and pixel
voxel – 3D, pixel – 2D
CT value of a voxel represent all messages of the elements in the voxel
fundamental principles of CT
image display image display
partial volume effectpartial volume effect
fundamental principles of CT
image display image display
enhancement CT high density contrast agent injected into veinintro-vascular/-tissue ( extracellular space) CT scan density contrast
hypersensitivenessnephrotoxitity
enhancement CT high density contrast agent injected into veinintro-vascular/-tissue ( extracellular space) CT scan density contrast
hypersensitivenessnephrotoxitity
fundamental principles of CT
enhancement CT high density contrast agent injected into veinintro-vascular/-tissue ( extracellular space) CT scan density contrast
hypersensitivenessnephrotoxitity
enhancement CT high density contrast agent injected into veinintro-vascular/-tissue ( extracellular space) CT scan density contrast
hypersensitivenessnephrotoxitity
fundamental principles of CT
enhancement CT high density contrast agent injected into veinintro-vascular/-tissue ( extracellular space) CT scan density contrast
hypersensitivenessnephrotoxitity
enhancement CT high density contrast agent injected into veinintro-vascular/-tissue ( extracellular space) CT scan density contrast
hypersensitivenessnephrotoxitity
fundamental principles of CT
IndicationsNo absolute contraindication, suitable for emergency and serious cases exam
Single imaging factor , image interpretation easily ,anatomy clear and detailed
deformation 、 infection 、 trauma 、 neoplasm…
LimitationsLow soft tissue resolution , difficult to detect lesion with small density difference from neighbor structure
Low sensitivity for the lesion with slight gross change
Contrast agent using
IndicationsNo absolute contraindication, suitable for emergency and serious cases exam
Single imaging factor , image interpretation easily ,anatomy clear and detailed
deformation 、 infection 、 trauma 、 neoplasm…
LimitationsLow soft tissue resolution , difficult to detect lesion with small density difference from neighbor structure
Low sensitivity for the lesion with slight gross change
Contrast agent using
fundamental principles of CT
Questions to think of with the lecture
What is X ray? What kinds of the features of it are useful or harmful?
What are the two steps of X ray imaging?
How is the grey scale of bone, muscle and air in the X ray film?
What is the main difference between the CT imaging and the image of X ray film?
What are same and what are different between the processes of CT imaging and imaging of X ray projection?
Is the meaning of a CT axial imaging and a section of a body specimen in same location identical?
What is X ray? What kinds of the features of it are useful or harmful?
What are the two steps of X ray imaging?
How is the grey scale of bone, muscle and air in the X ray film?
What is the main difference between the CT imaging and the image of X ray film?
What are same and what are different between the processes of CT imaging and imaging of X ray projection?
Is the meaning of a CT axial imaging and a section of a body specimen in same location identical?