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IMAGE GENERATION IN CT

IMAGE GENERATION IN CT. CT EXAM. PROTOCOL AND PARAMETERS SELECTION PATIENT POSITIONING SCANNING DATA RECONSTRUCTION IMAGE DISPLAY. PROTOCOL AND TECHNIQUE SELECTION. PROTOCOL PARAMETERS SCANNING MODE kVp mA Time RECONSTRUCTION PATIENT POSITION PATIENT ORIENTATION SFOV DFOV.

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IMAGE GENERATION IN CT

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  1. IMAGE GENERATION IN CT

  2. CT EXAM • PROTOCOL AND PARAMETERS SELECTION • PATIENT POSITIONING • SCANNING • DATA RECONSTRUCTION • IMAGE DISPLAY

  3. PROTOCOL AND TECHNIQUE SELECTION • PROTOCOL • PARAMETERS SCANNING MODE kVp mA Time RECONSTRUCTION PATIENT POSITION PATIENT ORIENTATION SFOV DFOV

  4. PROTOCOL • PEDIATRIC OR ADULT • HEAD, ABDOMEN, EXTREMITIES • VASCULAR OR REGULAR

  5. SCANNING MODE • AXIAL (SLICE BY SLICE) • SPIRAL (HELICAL)

  6. TECHNIQUE • kVp • mA • time

  7. RECONSTRUCTION • SECTION THICKNESS • SECTION INDEX • ALGORITHM

  8. PATIENT POSITION • SUPINE OR PRONE • BODY PART UNDER SCRUTINY MUST BE PLACED IN THE ISOCENTER OF THE SCANNER

  9. PATIENT ORIENTATION • HEAD FIRST • FEET FIRST

  10. SFOV SCANNING FIELD OF VIEW (CALLIBRATION FIELD OF VIEW) • AREA WITHIN THE GANTRY’S ISOCENTER FROM WHICH THE RAW DATA IS ACQUIRED DURING THE SCAN. IT DEPENDS ON THE NUMBER OF DETECTORS ACTIVATED TO COLLECT DATA.

  11. LARGE SFOV

  12. SMALL SFOV

  13. SMALL SFOV SFOV

  14. LARGE SFOV SFOV

  15. CHOOSE THE SMALLEST SFOV THAT WOULD ACCOMMODATE BODY PART FOR BEST RESOLUTION

  16. IF BODY PART LIES OUTSIDE SFOV NO DATA WILL BE COLLECTED FOR THAT PART THAT EXTEND BEYOND. IT ALSO CAUSES OUT OF FIELD ARTIFACT

  17. OUT OF FIELD ARTIFACT

  18. DFOV – DISPLAYED FIELD OF VIEW (ZOOM OR TARGET) • DETRMINES HOW MUCH RAW DATA FROM WITHIN SFOV WILL BE UTILIZED TO CREATE AN IMAGE.

  19. SFOV DFOV

  20. DISPLAYED FOV vs SCANNING FOV • DFOV CAN BE EQUAL OR LESS OF SFOV

  21. SMALL DFOV LARGE FOV SMALL PIXEL LARGE PIXEL DFOV VS PIXEL SIZE LARGE DFOV LOW SPATIAL RESOLUTION LOW VISIBILITY OF DETAIL

  22. LARGE DFOV

  23. SMALL DFOV

  24. DFOV

  25. DFOV

  26. PIXEL SIZE PIXEL SIZE= DFOV (mm)/ MATRIX SIZE

  27. SAMPLE

  28. SCANNING • TOPOGRAM • REGULAR SCAN

  29. TOPOGRAM (SCOUT) • TUBE DOES NOT REVOLVE AROUND THE PATIENT

  30. AP SCOUT • TUBE SUSPENDED ABOVE PATIENT DURING SCOUT GENERATION TUBE

  31. LAT SCOUT • TUBE AT THE 90º ANGLE TO PATIENT

  32. REGULAR SCAN

  33. I, II, AND III GENERATION • CONTINUOUS DATA ACQUSITION GEOMETRY

  34. IV GENERATION • STATIONARY DATA ACQUSITION GEOMETRY

  35. REGULAR SCAN • AXIAL (CONVENTIONAL, SLICE-BY-SLICE) • SPIRAL

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

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

  38. TOTAL NUMBER OF TRANMISSION MEASUREMENTEQUALSNUMBER OF VIEWS XNUMBER OF RAYS IN EACH VIEW

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