1. Computer Tomography By Moustafa M. Mohamed

2. Introduction to Medical Imaging Uses of medical imaging Obtain information about internal body organs or the skeleton to determine a patient’s physical state. NON Invasive Imaging Modalities: * X-ray (plan, Dental, Panorama, Mammo, Angio, …) * C.T * Ultrasound * MRI * Gamma Camera * PET SPECT

3. Types of image 1) Projections 2) Dimensional 3D & 4D

4. 3) Slices Trans axial - plane normal to a vector from head to toe. Coronal - plane normal to a vector from front to back Sagittal - plane normal to a vector from left to right. Oblique - a slice that is not (at least approximately) one of the above.

5. Filament connection Filament Anode Focal Area Target (tungsten) Glass envelope Focussing cup Window Principles of X-ray tube Anode connection + kV High Voltage supply +

9. CAT Scan ---- Computerized Axial Tomography CT Scan ---- Computed Tomography Produce thin cross-sectional images Non-traumatic radiographic technique

10. Based on Reconstruction of a tomographic plane of the body (a slice) from a large number of collected x- ray absorption measurements taken during a scan around the body’s periphery.

11. X-ray tube Detector Array Detector cell Image Reconstruction

13. CT Generations 4 Generations Based on Tube / Detector setting

14. First generation CT-scanner “Translate – Rotate” Translation Rotation Single Detector Cell First Translation then Rotation.

15. Second generation CT-scanner “Translate – Rotate” Array of Detector Cell ( e.g. 20) First Translation then Rotation. Scan Time could be reduced to 1/10

16. Third generation CT-scanner “Rotate – Rotate” Rotation movement Array of Detector Cell ( e.g. 896) NO Translation movement. Scan Time Reduced.

17. Fourth generation CT-scanner Tube rotates, Detector is stationary (full ring of detectors)

18. Fifth generation CT-scanner

22. Main Component of CT scan Gantry Consol Patient CouchControl Unit

23. DAS Pre-Proc Reconstructor TUBE DETECTOR CT Scan General Block Diagram

25. Tilting (+/-20 to +/-30) SLIDE HEIGHT Operator Controls Positioning Lights Emergency Stop

26. Gantry (X-ray path) Detector TUBE Collimator Wedge Beamtrimmer Slit X-ray beam T Detector defines the slice thickness metal plate with a hole Limit x-ray beam Prevent detector overflow Limit x-ray beam Used for thin slices (1 – 3 mm)

27. Data Transfer from DAS to Console In non-continuous rotating system the data is transferred from the DAS to the Console via parallel cable. D.A.S. CONSOLE

28. Data Transfer from DAS to Console In continuous rotating system the DAS data is: converted from parallel to serial, transferred (via slipring or optical) converted back from serial to parallel. D.A.S. CONSOLE Parallel to Serial to Parallel