1. CT QUALITY MANAGEMENT

2. SPATIAL RESOLUTION CONTRAST RESOLUTION NOISE IMAGE ARTIFACTS RADIATION DOSE

3. TESTS AVERAGE CT NUMBER AND NOISE CROSS-FIELD UNIFORMITY SPATIAL RESOLUTION LOW CONTRAST RESOLUTION SLICE THICKNESS LASER LIGHT ACCURACY

4. NOISE IN CT FLUCTUATION OF CT# BETWEEN POINTS IN THE IMAGE FOR A SCAN OF UNIFORM MATERIAL SUCH WATER.

5. NOISE CAN BE MEASURED BY SCANNING A WATER PHANTOM AND COMPUTING THE MEAN AND STANDARD DEVIATION FOR FOR A REGION OF INTEREST. (ROI)

6. AVERAGE CT NUMBER

7. AVG. CT #

8. AVG. CT NUMBER WATER – CT# = 0, +- 3 HU AIR – CT# = -1,000, +- 5 HU NOISE +- 10 HU

9. CAUSE OF FAILURE MISCALIBRATION OF THE CT # GENERATING ALGORITHM

10. FREQUENCY CT NUMBER OF WATER – DAILY CT NUMBER OF AIR – MONTHLY

11. CROSS-FIELD UNIFORMITY THE UNIFORMITY OF CT # THROUGHOUT THE ENTIRE SCAN FIELD OF VIEW IS ONE INDICATION THAT CT SCANNER IS PERFORMANCE IS ACCEPTABLE. IT REFERS TO THE VALUES OF THE PIXELS IN THE RECONSTRUCTED IMAGE THEY SHOULD BE CONSTANT AT ANY POINT IN THE IMAGE OF PHANTOM

13. UNIFORMITY NO MORE THAN 2 HU BETWEEN CENTER AND PERIPHERY

14. CAUSE OF FAILURE NOISE

15. FREQUENCY DAILY

16. QUALITY MEASUREMENT METHODS OF SPATIAL RESOLUTION PSF- POINT SPREAD FUNCTION LSF- LINE SPREAD FUNCTION CTF – CONTRAST SPREAD FUNCTION MTF- MODULATION TRANSFER FUNCTION

17. MTF MODULATION TRANSFER FUNCTION MOST COMMONLY USED TO DESCRIBE SPATIAL RESOLUTION IN CT

18. MTF MTF OF 1 – 100% TRANSFER OF OBJECT TO IMAGE MTF OF 0 – 0% TRANSFER OF OBJECT TO IMAGE

19. SPATIAL RESOLUTION Lp/cm

20. SPATIAL RESOLUTION LARGE OBJECTS – LOW S.F. SMALL OBJECTS – HIGH S.F.

21. SPATIAL RESOLUTION 1 5

22. ABSOLUTE SIZE OF AN OBJECT IN CT IT’S EQUAL TO THE RECIPROCAL OF THE SPATIAL FREQUENCY CT SCANNER SPATIAL FREQUENCY- 15 lp/cm. WHAT SIZE OF AN OBJECT CAN THE SCANNER RESOLVE 1/15 = 0.06 mm/lp= 0.6 cm/lp 0.6 /2 = 0.3 mm object

23. Resolution in CT Spatial ResolutionContrast Resolution

24. SPATIAL RESOLUTION DEGREE OF BLURRING IN THE IMAGE MEASURE OF THE ABILITY TO DISCRIMINATE OBJECTS OF VARYING DENSITY A SMALL DISTANCE APART AGAINST A UNIFORM BACKGROUND

25. HIGH CONTRAST PHANTOM

28. SPATIAL RESOLUTION 0.45 –0.15 lp/mm (4.5 –15 lp/cm)

29. CAUSE OF FAILURE EXCESSIVE FSS MECHANICAL WEAR DETECTOR VIABRATIONS

30. FREQUENCY ONCE A MONTH

31. LOW CONTRAST RESOLUTION ( TISSUE RESOLUTION) THE ABILITY OF AN IMAGING SYSTEM TO DEMONSTRATE SMALL CHANGES IN TISSUE CONTRAST

32. LOW CONTRAST PHANTOM

34. EXPECTED RESULTS SMALLEST HOLES THAT COULD BE IMAGED SHOULD BE 3 mm IN DIAMETER OR SMALLER FOR 0.5% DENSITYU DIFFERENCE.

35. CAUSE OF FAILURE NOISE

36. SLICE THICKNESS IF 5 MM THICKNESS OR MORE IS SELECTED IT SHOULD NOT VARY BY MORE THAN +- 1mm. IF IT IS 5 mm OR LESS IT SHOULD NOT VARY BY MORE THAN +- 0.5 mm.

37. CAUSE OF FAILURE MISCALIBRATION OF THE COLLIMATION MECHANISM

38. FREQUENCY SEMIANNUALLY

39. LASER LIGHT ACCURACY LIGHT AND RADIATION FIELD SHOULD COINCIDE TO 2mm

40. CAUSE OF FAILURE TUBE MISALIGNMENT LASER MISALIGNMENT

41. FREQUENCY ANNUALLY