Examples of Good & Bad Practice (physical factors)

1. Examples of Good & Bad Practice (physical factors) L 12a

2. Educational Objectives • How wedge filter & field size affect the skin dose • When and how to use wedge filter Lecture 12 : Examples of Good & Bad Practice (physical factors)

3. Answer True or False • Wedge filter should not be used in flat panel detectors. • Size of the radiation field is similar in all the cardiology procedures, then collimation is not necessary. • In cardiology procedures, the hands of the medical specialists are never in the direct radiation field. Lecture 12 : Examples of Good & Bad Practice (physical factors)

4. Topics included • Use of wedge filter. • Collimation (filed size). • Use of cine instead of fluoroscopy. • Use of cine to verify the proper position of the table. • Hands inside the direct beam. Lecture 12 : Examples of Good & Bad Practice (physical factors)

5. Philips systems Lecture 12 : Examples of Good & Bad Practice (physical factors)

6. Series 14: KVP: 88 Distance source to detector: 1048 Exposure time 8 X-ray tube current 467 Intensifier size 169.9 mm Positioner primary angle 5.2 (LAO) Positioner secondary angle 28.3 13 Sep 04; 40414 Example of lack of wedge filter use in a left projection. Image quality is not good (too bright in the upper left corner of the image) and in addition, more dose per frame than necessary. Bad practice!. Lecture 12 : Examples of Good & Bad Practice (physical factors)

7. Series 21: KVP 87 Distance source to detector 995 Exposure time 8 X-ray tube current 472 Positioner primary angle - 41.1 (RAO) Positioner secondary angle 28.8 13 Sep 04; 40414 Example of lack of wedge filter use in a right projection. Image quality is not good (too bright in the upper right corner of the image) and in addition, more dose per frame than necessary. . Bad practice!. Lecture 12 : Examples of Good & Bad Practice (physical factors)

8. Series : 6 (0008,0020) : Study Date : 21/09/2004 (0008,0080) : Institution Name : HOSPITAL SEVERO OCHOA (0008,1090) : Manufacturer's Model Name : INTEGRIS Allura Flat Detector (0018,0060) : KVP : 78.0 (0018,1110) : Distance Source to Detector : 1.08 (0018,1111) : Distance Source to Patient : 0.765 (?) (0018,1150) : Exposure Time : 6 (0018,1151) : X-ray Tube Current : 812 (0018,1510) : Positioner Primary Angle : -31.2 (0018,1511) : Positioner Secondary Angle : 32.2 Example of appropriate use of the wedge filter. (flat panel). Good practice!. Lecture 12 : Examples of Good & Bad Practice (physical factors)

9. No wedge filter used. Image partially saturated. Bad practice!. Lecture 12 : Examples of Good & Bad Practice (physical factors)

10. 0.5 mGy/fr 0.8 mGy/fr (60% more) Lecture 12 : Examples of Good & Bad Practice (physical factors)

11. Image Intensifier versus Flat detector improper filtering causes image deterioration (II Philips Integris H3000) proper filtering Filtering prevents image saturation in low absorption areas Lecture 12 : Examples of Good & Bad Practice (physical factors)

12. Image Intensifier versus Flat detector Image from GE-INNOVA FD Improper filtering does not cause image deterioration Lecture 12 : Examples of Good & Bad Practice (physical factors)

13. Use of wedge filter in right projections

14. Effect of the wedge filter in skin dose distribution (right projections). Saving skin dose and improving image quality.Good practice!. Lecture 12 : Examples of Good & Bad Practice (physical factors)

15. Lecture 12 : Examples of Good & Bad Practice (physical factors)

16. Areas in red are saturated in the slow film. Skin dose more than 0.8 Gy. Lecture 12 : Examples of Good & Bad Practice (physical factors)

17. Philips Integris: Use of wedge filter in left projections

18. Effect of the wedge filter in skin dose distribution (left projections). Saving skin dose and improving image quality. Good practice!. Lecture 12 : Examples of Good & Bad Practice (physical factors)

19. Lecture 12 : Examples of Good & Bad Practice (physical factors)

20. Areas in red are saturated in the slow film. Skin dose more than 0.8 Gy. Lecture 12 : Examples of Good & Bad Practice (physical factors)

21. Use of wedge filter in right and left projections

22. Lecture 12 : Examples of Good & Bad Practice (physical factors)

23. Lecture 12 : Examples of Good & Bad Practice (physical factors)

24. Areas in red are saturated in the slow film. Skin dose more than 0.8 Gy. Lecture 12 : Examples of Good & Bad Practice (physical factors)

25. Geometry with small field size

26. Lecture 12 : Examples of Good & Bad Practice (physical factors)

27. 68 cm2 28 cm2 26 cm2 Lecture 12 : Examples of Good & Bad Practice (physical factors)

28. Areas in red are saturated in the slow film. Skin dose more than 0.8 Gy. Lecture 12 : Examples of Good & Bad Practice (physical factors)

29. Geometry with big field size

30. Lecture 12 : Examples of Good & Bad Practice (physical factors)

31. 1.2 Gy 0.6 Gy 113 cm2 41 cm2 Lecture 12 : Examples of Good & Bad Practice (physical factors)

32. Areas in red are saturated in the slow film. Skin dose more than 0.8 Gy. Lecture 12 : Examples of Good & Bad Practice (physical factors)

33. No wedge filter used. Geometry with big radiation field size. Overlapping of radiation fields could occur.

34. Lecture 12 : Examples of Good & Bad Practice (physical factors)

35. 319 cm2 234 cm2 91 cm2 Lecture 12 : Examples of Good & Bad Practice (physical factors)

36. Lecture 12 : Examples of Good & Bad Practice (physical factors) Areas in red are saturated in the slow film. Skin dose more than 0.8 Gy.

37. Hands in the direct radiation field

38. This is a bad practice. The hand of the cardiologist is in the direct radiation field during fluoroscopy. This should be avoided. Lecture 12 : Examples of Good & Bad Practice (physical factors)

39. This is a bad practice. The hand of the cardiologist is in the direct radiation field and a cine run is acquired (dose is a factor of 10 higher than during fluoroscopy). This should be avoided. Lecture 12 : Examples of Good & Bad Practice (physical factors)

40. This is a bad practice. The hand of the cardiologist is in the direct radiation field and a (second) cine run is acquired (dose is a factor of 10 higher than during fluoroscopy). This should be avoided. Lecture 12 : Examples of Good & Bad Practice (physical factors)

41. The use of cine instead of fluoroscopy

42. Comments • One series with more that 999 frames (more than 80 seconds) • Probably a fellow uses cine instead of fluoroscopy (images on that series support this assumption). • 80 seconds of fluoroscopy (low mode) could be 30 mGy in the skin. 1000 frames can be 500 mGy (76 kV; 857 mA; 7 ms)!!!. • Lateral projection: 89º; -5º. The sternum of the patient was in the beam during part of the series. Table is moved up. Lecture 12 : Examples of Good & Bad Practice (physical factors)

43. The sternum of the patient is now in the beam, Fellow is trying to find the good position at the isocenter. Table should be moved up in this case. Lecture 12 : Examples of Good & Bad Practice (physical factors)

44. Answer True or False • Wedge filter should be used in the same position for right and left projections. • Wedge filter improve the visualization of the images but increase the skin dose of the patient. • Typically one cine frame requires 10 times for dose at the entrance of the patient than a fluoroscopy image. Lecture 12 : Examples of Good & Bad Practice (physical factors)

45. Additional Information

46. Patients who had multiple coronary angiographies and who underwent more than four PTCAs. 7824 PTCAs performed during 14 years was analysed. • 14 patients were included in the study. Each patient had undergone between 4 and 14 coronary angiographies and between 5 and 10 PTCAs, performed over a period of 2-10 years. Lecture 12 : Examples of Good & Bad Practice (physical factors)

47. Mean values of maximum skin dose per procedure were 217 mGy for the diagnostic studies and 391 mGy for the PTCAs. • Only a slight radiation skin injury was clinically demonstrated in one patient with a history of 10 coronary angiographies and 10 PTCAs (estimated maximum skin dose 9.5 Gy). Lecture 12 : Examples of Good & Bad Practice (physical factors)

48. CONCLUSION: • IC procedures performed on modern X-ray systems under QA programmes and by cardiologists trained in RP, repetition of procedures is not the main cause of possible skin radiation injuries. Lecture 12 : Examples of Good & Bad Practice (physical factors)