CT Radiation Dose Optimization

Targeted CE per ARRT’s Discipline, Category, and Subcategory classification for enrollments starting after August 15, 2023:

Computed Tomography: 2.75
Safety: 2.75
Radiation Safety and Dose: 2.75

Registered Radiologist Assistant: 2.75
Safety: 2.75
Patient Safety, Radiation Protection, and Equipment Operation: 2.75

Outline

1. Introduction
2. CT Scanning: Data and Risk Projection
3. Important CT Scanning Parameters
   1. Scanner Geometry
   2. Tube Current and Potential
   3. Scanning Modes
   4. Scanning Length
   5. Collimation, Table Speed, and Pitch
   6. Gantry Rotation Time
   7. Sheilding
4. Radiation Dose Reduction and Judicious Practices
5. Modulation of CT Parameters for Dose Reduction
   1. Weight
   2. Cross-sectional Dimension
6. Literature on CT Radiation Reduction
   1. Chest CT Scanning
   2. CT in Pediatric Patients
   3. CT Colonography
   4. CT for Urinary Tract Calculi
7. Technologic Advances for Radiation Reduction
   1. X-ray Beam Utilization
   2. X-ray Filtration
   3. Automatic Modulation of Tube Current
   4. Projection Adaptive Reconstruction Filters
   5. Computer Simulated Dose-Reduction Software
   6. Filters
8. Conclusion

Objectives

Upon completion of this course, students will:

1. understand who is responsible for radiation dose reduction in CT
2. be familiar with deterministic risk of radiation exposure
3. know the stochastic effects of radiation
4. understand the estimated cancer risk from abdominal CT
5. know how doubling patient distance from the radiation source affects radiation dose
6. be familiar with the law relating radiation intensity and distance
7. know how tube current is related to patient dose
8. understand how reduction in tube current affects dose, image noise and image contrast
9. understand how tube potential affects dose, image noise and image contrast
10. know how multidetector row helical CT is related to radiation dose
11. understand how dose is related to scanning length
12. be familair with the ratio of table feed per rotation to beam width
13. know how increased pitch affects helical artifacts, section broadening and spatial resolution
14. understand how dose is related to pitch
15. know how dose is related to changing the pitch
16. understand when thin collimation should be used
17. know the tradeoffs between image quality and reduced rotation time
18. be familiar with radiosensitive organs
19. be familiar with particularly radiosensitive organs
20. know who clinical guidelines can be used to advise on the appropriateness of exams
21. understand the role of other imaging modalities
22. know which benign condition is responsible for the largest cumulative CT radiation dose
23. understand what uniform imaging protocols for exams should be based on
24. know what can be adjusted according to patient dimensions for dose modulation
25. know what basing dose modulation on may result in large fluctuations in image noise
26. understand how patient dimensions can be obtained
27. know why chest CT requires less radiation than does abdominal CT
28. be familiar with pediatric protocols
29. be familiar with CT colonography
30. know the differences between low-dose CT colonography and standard abdominal/pelvic CT
31. understand how tube current for a urinary calculi exam can be reduced
32. know how prepatient tracking reduces dose
33. know how X-ray filtration reduces dose
34. understand what can be done to harden the x-ray beam
35. know what z-axis current modulation is based on
36. understand why tube current is adjusted in z-axis modulation
37. know what angular modulation is most effective for
38. know how projection-adaptive reconstruction filters improve image quality
39. understand how projection-adaptive reconstruction filters work
40. be familiar with software used to simulate image quality