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PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at...

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PRINCIPLES OF CT Dr Mohamed El Safwany, MD
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Page 1: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

PRINCIPLES OF CT

Dr Mohamed El Safwany, MD

Page 2: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

Intended learning outcome

• The student should learn at the end of this lecture principles of CT.

Page 3: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

TOMOGRAPHY

TOMOS---SECTION

TOMOGRAPHY

TOMOS---SECTION

Page 4: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

RADIOGRAPHY LIMITATIONS

• SUPERIMPOSITION

• DIFFICULTY IN DISTINGUISHING BETWEEN HOMOGENOUS OBJECTS OF NON-UNIFORM THICKNESS.

Page 5: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

SUPERIMPOSITION

Page 6: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

RADIOGRAPHY LIMITATIONTISUE

DIFFERENCE SENSITIVITY >10%

Page 7: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

TOMOGRAPHY (CONVENTIONAL)

• ELIMINATES TISSUE SUPERIMPOSITION

• INCREASES CONTRAST OF LOW SUBJECT CONTRAST TISSUES

Page 8: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

TOMOGRAPHY

Page 9: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

TOMOGRAPHY

Page 10: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

TOMOGRAPHY LIMITATIONS

MOTION BLURR

Page 11: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

CT ADVANTAGES

Page 12: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

LIMITATIONS OF CT

• UNABLE TO DIFFERENTIATE BETWEEN TISSUES WITH SLIGHT CONTRAST DIFFERENCES < 1%.

Page 13: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.
Page 14: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

GOALS OF CT

• MINIMAL SUPERIMPOSITION

• IMAGE CONTRAST IMPROVEMENT

• SMALL TISSUE DIFFERENCE RECORDING

Page 15: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

CT DATA AQUISITION

Page 16: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.
Page 17: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

TRANSMISSION

RELATIVE TRANSMISSION=Io/I

Page 18: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

MODERN SCANNER

Page 19: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

CT MAIN SYSTEMS

• IMAGING SYSTEM

• COMPUTER SYSTEM

• DISPLAY, RECORDING, STORAGE SYSTEM

• DATA ACQUISITION SYSTEM

Page 20: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

IMAGING SYSTEM

• PRODUCTION OF X-RAYS

• SHAPING OF X-RAY BEAM ENERGY

• FILTERING X-RAY BEAM

Page 21: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

SCANNER

GANTRY

TABLE/COUCH

Page 22: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

GANTRY INSIDE

Page 23: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

COMPUTER SYSTEM

• RECONSTRUCTION AND POSTPROCESSING

• CONTROL OF ALL SCANNER COMPONENTS

• CONTROL OF DATA ACQUSITION, PROCESSING, DISPLAY.

• DATA FLOW DIRECTION

Page 24: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

COMPUTER SYSTEM IN CT

• MINICOMPUTERS

Page 25: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

IMAGE DISPLAY, RECORDING, STORAGE

• DISPLAYS IMAGE ( OUTPUT FROM COMPUTER)

• PROVIDES HARD COPY OF THE IMAGE

• FACILITATES THE STORAGE AND RETRIEVAL OF DIGITAL DATA

• COMMUNICATES IMAGES IN THE NETWORK

Page 26: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

DATA ACQUISITION SYSTEM (DAS)

• SET OF ELECTRONICS BETWEEN DETECTORS AND HOST COMPUTER.

Page 27: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

COORDINATE SYSTEM IN CT

X

Page 28: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

COORDINATE SYSTEM IN CT

Y

Page 29: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

COORDINATE SYSTEM IN CT

Z

Page 30: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

COORDINATE SYSTEM IN CT

ISO-CENTER

Page 31: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.
Page 32: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

SCAN FOV

SFOV

DETECTORS

Page 33: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

DFOV – DISPLAYED FIELD OF VIEW

• SIZE DISPLAYED ON THE MONITOR

Page 34: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

PIXEL SIZE

PIXEL SIZE= DFOV (mm)/ MATRIX SIZE

Page 35: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

PIXEL vs VOXEL

PIXEL VOXEL

Page 36: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

PIXEL SIZE DEPENDS ON:

• MATRIX SIZE

• FOV

Page 37: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

VOXEL SIZE DEPENDS

• FOV• MATRIX SIZE• SLICE THICKNESS

Page 38: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

IMAGE DISPLAY

Page 39: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

IN CT DIGITAL RECONSTRUCTED IMAGE IS

CONVERTED IMAGE IS CONVERTED INTO A GRAY

SCALE IMAGE.

Page 40: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.
Page 41: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.
Page 42: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

CT # vs BRIGHTNESS LEVEL

+ 1000

-1000

Page 43: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

CT #1000

Page 44: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

CT # - 500

Page 45: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

CT # OF CYST5

Page 46: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

CT # OF LIPOMA ( FATTY TUMOR)

                                                                        

                                                

-100

Page 47: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.
Page 48: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

SCANNING

Page 49: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

TECHNIQUE

• kVp

• mA

• TIME

• SLICE THICKNESS

• SLICE INCREMENTATION

Page 50: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

PATIENT ORIENTATION• HEAD FIRST • FEET FIRST

Page 51: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.
Page 52: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

SCANNING

• TOPOGRAM

• REGULAR SCAN

Page 53: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

TOPOGRAM (SCOUT)

• TUBE DOES NOT REVOLVE AROUND THE PATIENT

Page 54: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

AP SCOUT

• TUBE SUSPENDED ABOVE PATIENT DURING SCOUT GENERATION

TUBE

Page 55: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

LAT SCOUT

• TUBE AT THE 90º ANGLE TO PATIENT

Page 56: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

AXIAL SCAN

• TABLE STOPS AT THE SCANNING POSITION AND THE TUBE ROTATES AROUND A PATIENT.

Page 57: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

SPIRAL

• PATIENT CONTINUOUSLY MOVES IN THE Z-AXIS DIRECTION WHILE THE TUBE ROTATES AROUND.

Page 58: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

CONVENTIONAL AND SPIRAL/HELICAL CT

Page 59: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

ADVANTAGE OF SPIRAL IMAGING OVER CONVENTIONAL

• SPEED

Page 60: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

CT SPECIAL APPLICATIONS

Page 61: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

CARDIAC ANGIOGRAPHY

Page 62: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

VIRTUAL ENDOSCOPY

Page 63: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

RADIATION TREATMENT

Page 64: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

3D IMAGING

Page 65: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.
Page 66: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

Text Book

• David Sutton’s Radiology

• Clark’s Radiographic positioning and techniques

Page 67: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

Assignment

• Two students will be selected for assignment.

Page 68: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

Question

• Define topogram and tomogram?

Page 69: PRINCIPLES OF CT Dr Mohamed El Safwany, MD. Intended learning outcome The student should learn at the end of this lecture principles of CT.

• Thank You


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