1. International Atomic Energy Agency Angiography Equipment L 4

2. Radiation Protection in Cardiology Lecture 4: Angiography equipment2 Educational objectives What are equipment standards for cath equipment (FDA, IEC), particular needs for pediatric patients. What to look for while establishing a cath lab. Importance of testing equipment performance.

3. Radiation Protection in Cardiology Lecture 4: Angiography equipment3 Equipment standards for Cath Lab

4. Radiation Protection in Cardiology Lecture 4: Angiography equipment4 X-Ray Equipment Standards And Regulations Standards are consensus guides from the manufacturing community, not regulatory Several groups set standards regarding equipment, e.g., International Electrotechnical Equipment (IEC) Apply to electrical, mechanical, and radiation safety Apply to equipment at time of manufacture and installation

5. Radiation Protection in Cardiology Lecture 4: Angiography equipment5 What to look for while establishing a cath. lab. If the relevant Standards are fulfilled. If a medical physicist is available. If radiation protection tools are available. If patient dose measuring and recording system is available. If acceptance tests, commissioning and quality assurance programme have been foreseen.

6. Radiation Protection in Cardiology Lecture 4: Angiography equipment6 What to look for while establishing a cath. lab. If the X rays system selected is appropriate for the procedures to be carried out in the catheterization laboratory. If some other relevant information described in ACC/AHA Guidelines and AAPM-70 (described in this lecture) have been taken into account.

7. Radiation Protection in Cardiology Lecture 4: Angiography equipment7Outline FDA, IEC and ACR recommendations concerning X-ray equipment for cardiology. AAPM report and specific pediatric equipment recommendations. Key topics for cardiac X-ray equipment. IAEA survey and importance of testing equipment. Patient dose reports and DICOM header information.

8. Radiation Protection in Cardiology Lecture 4: Angiography equipment8 Limitation in entrance exposure rate Federal Register: May 19, 1994. 21 CFR Part 1020. Federal Performance Standard for Diagnostic X-Ray Systems and Their Major Components; Final Rule. DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration

9. Radiation Protection in Cardiology Lecture 4: Angiography equipment9 Limitation in entrance exposure rate The Standard for Diagnostic X Ray Systems (May 19, 1994), limits the entrance exposure rate of fluoroscopic x ray systems during normal fluoroscopy to 10 R/min unless an optional high-level control (HLC) is activated. If HLC is activated, the entrance exposure rate must be limited to 20 R/min. The entrance exposure rate limits do not apply during the recording of images.

10. Radiation Protection in Cardiology Lecture 4: Angiography equipment10 Measuring entrance dose and image quality Test object to measure image quality, at the isocenter Flat ionisation chamber to measure phantom entrance dose

11. Radiation Protection in Cardiology Lecture 4: Angiography equipment11 Typically we can find the following fluoroscopy setting:

12. Radiation Protection in Cardiology Lecture 4: Angiography equipment12 Typically we can find the following cine setting

13. Radiation Protection in Cardiology Lecture 4: Angiography equipment13 Proposed Rule December 10, 2002

14. Radiation Protection in Cardiology Lecture 4: Angiography equipment14 mGy (total) mGy/min (at 15 cm from the isocenter towards the x-ray source) Fluoroscopy time

15. Radiation Protection in Cardiology Lecture 4: Angiography equipment15

16. Radiation Protection in Cardiology Lecture 4: Angiography equipment16 Fluoroscopic equipment manufactured on or after May 19, 1995: Shall not be operable if AKR is higher than 88 mGy/min (10 R/min). Exceptions: When a mode a high-level control is activated: 180 mGy/min (20 R/min). A continuous signal audible to the fluoroscopist shall indicate that the high-level control is being employed. During the recording of images (archiving of fluoroscopic or radiographic images in analog format with a video-tape or video-disc recorder does not qualify as an exception). Limits: 88 mGy/min 180 mGy/min

17. Radiation Protection in Cardiology Lecture 4: Angiography equipment17 IEC Standard 2000

18. Radiation Protection in Cardiology Lecture 4: Angiography equipment18 IEC standard on Interventional Radiology Radioscopically guided invasive (and interventional) procedures. Interventional reference point. Isokerma maps shall be provided. The anti-scatter grid should be removable without the use of tools. Dosimetric indications: reference air kerma rate, cumulative reference air kerma. cumulative area kerma product, (shall be accurate to within  50 %). Supplementary indications: cumulative time of radioscopy, cumulative number of radiographic irradiations, integrated reference air kerma.

19. Radiation Protection in Cardiology Lecture 4: Angiography equipment19 Transmission chamber and collimators (Siemens system)

20. Radiation Protection in Cardiology Lecture 4: Angiography equipment20

21. Radiation Protection in Cardiology Lecture 4: Angiography equipment21 Collimation: Dual-shape collimators incorporating both circular and elliptical shutters may be used to modify the field for cardiac contour collimation. Partially absorbent contoured filters are also available to control the bright spots produced by the lung tissue bordering the heart.

22. Radiation Protection in Cardiology Lecture 4: Angiography equipment22 Philips systems

23. Radiation Protection in Cardiology Lecture 4: Angiography equipment23 Example of the influence of wedge filter in the skin dose (Vano)

24. Radiation Protection in Cardiology Lecture 4: Angiography equipment24 Image intensifiers. Because of the necessity of imaging large fields (e.g., for ventriculography, aortography) as well as small fields (coronary arteries), multimode (double or triple) cesium iodide image intensifiers are recommended. Formats available vary with the manufacturer but are typically 9 in/ 6 in/4.5 in (9/6/4.5), 9/6, 10/4, and 9/5.

25. Radiation Protection in Cardiology Lecture 4: Angiography equipment25 Patient and Equipment Support: The ability to obtain very steep sagittal plane angulation (in excess of 45 ) is desirable. An image intensifier with a diameter of more than 9 in is not recommended for cardiac catheterization laboratories because its size interferes with the ability to obtain steep sagittal angulation.

26. Radiation Protection in Cardiology Lecture 4: Angiography equipment26 The operator should be made aware of the cumulative amount of exposure time during the procedure. In training programs there should be a limit to the amount of fluoroscopic time granted to a trainee to complete a specific task, based on a number of considerations such as the progress being made and the complexity of the procedure.

27. Radiation Protection in Cardiology Lecture 4: Angiography equipment27 A freely movable lead glass or acrylic shield suspended from the ceiling should be used. Its sterility may be maintained by using disposable plastic covers. Each procedure room should have a detailed determination of exposure levels performed by a qualified radiation physicist. There is a tendency in the busy laboratory to assign a low priority to preventive maintenance and quality assurance inspections.

28. Radiation Protection in Cardiology Lecture 4: Angiography equipment28 AAPM-70 (2001) The generator should be capable of generating 80 to 100 kilowatts (kW) of power. The generator design should result in “square wave” kVp pulses to achieve optimum patient dose savings.

29. Radiation Protection in Cardiology Lecture 4: Angiography equipment29 AAPM-70 (2001) Several manufacturers are using relatively thick copper filtration and reduced kVp during fluoroscopy to generate an energy spectrum better matched to the K-edge of iodine contrast media. This technique requires high fluoroscopic tube currents with the benefit of reducing patient exposure to radiation while improving image contrast.

30. Radiation Protection in Cardiology Lecture 4: Angiography equipment30 AAPM-70 (2001) For adult studies, a 9 to 11 inch (23 to 27 cm) size is used. Pediatric cardiac studies use smaller FoVs due to the small size of the pediatric heart. The 4.5 inch (11 cm) FoV would be commonly employed for most pediatric imaging studies.

31. Radiation Protection in Cardiology Lecture 4: Angiography equipment31 AAPM-70 (2001). Pediatrics. If the cath lab will serve the pediatric population, the generator design should allow high quality imaging on patients which range in size from 3 to 140 kilograms (kg). This wide range of patient size places additional demands on the design of the generator.

32. Radiation Protection in Cardiology Lecture 4: Angiography equipment32 AAPM-70 (2001). Pediatrics. The generator design should allow the mAs loading of the tube per cine pulse to be varied from as little as 0.1 mAs (100 mA and 1 msec) up to 6 mAs (e.g., 800 mA and 7 msec) as a function of patient size in order to maintain a kVp operating range of 65 to 75 kVp.

33. Radiation Protection in Cardiology Lecture 4: Angiography equipment33 AAPM-70 (2001). Pediatrics. Cine frame rate capability should extend up to at least 60 fps for small children. The generator should support an x-ray tube with a minimum of three focal spots. Patients up to 3 to 4 years old can be imaged with an 0.3 mm focal spot size, and patients up to 8 to 9 years old can be imaged with cine using an 0.6 mm focal spot.

34. Radiation Protection in Cardiology Lecture 4: Angiography equipment34 AAPM-70 (2001). Pediatrics. The 0.3 mm focal spot can also be used on small children by removing the anti- scatter grid and employing a geometric magnification factor up to 2. The geometrical magnification method for small children can also reduce patient dose because the electronic magnification modes of the image intensifier are avoided and the Bucky factor due to the grid is eliminated.

35. International Atomic Energy Agency Cardiology equipment key topics

36. Radiation Protection in Cardiology Lecture 4: Angiography equipment36 Key topics Spatial beam modulation: collimation (and virtual collimation), wedge filters, etc. Temporal beam modulation: pulsed fluoroscopy (grid controlled, temporal integration, etc). Beam quality modulation: extra filtering (Cu, Ta, etc). Last image hold. Patient dose measurement, display and archive. New detectors (dynamic flat panel), connectivity and DICOM compliance.

37. Radiation Protection in Cardiology Lecture 4: Angiography equipment37 Control panel indications (Siemens system)

38. Radiation Protection in Cardiology Lecture 4: Angiography equipment38 X-ray room indications (Siemens system)

39. Radiation Protection in Cardiology Lecture 4: Angiography equipment39 Key topics Ergonomy in the room and system geometry. Accidental stop of the system. Dosimetric indications in the system and inside the cath lab. Protective tools in the system. Operational modes and how they are settled. DICOM header information. On line audit possibilities.

40. Radiation Protection in Cardiology Lecture 4: Angiography equipment40 High filtration The introduction of additional filtration in the X ray beam (commonly copper filters) reduce the number of low energy photons and as consequence, saves skin dose for the patients.

41. Radiation Protection in Cardiology Lecture 4: Angiography equipment41 Additional Cu filters can reduce the skin dose by more than 70%. Some systems affer variable extra filtration (0.2 mm - 0.9 mm) that is automatically set according to patient weight and angulation of the C-arm. Automatic filter insertion try to keep the dose as low as possible without degrading image quality. Reduction of Radiation Exposure with extra filtration

42. Radiation Protection in Cardiology Lecture 4: Angiography equipment42 Pulsed fluoroscopy Pulsed fluoroscopy can be used as a method of reducing radiation dose, particularly when the pulse rate is reduced. But … pulsed fluoroscopy does not mean that dose rate is lower in comparison with continuous fluoroscopy!!. Dose rate depends of the dose per pulse and the number of pulses per second.

43. Radiation Protection in Cardiology Lecture 4: Angiography equipment43 Reduction of Radiation Exposure with virtual collimation Radiation-free Collimation. Manipulation of diaphragms in Last Image Hold. No fluoroscopy required.

44. International Atomic Energy Agency Example of X-ray system setting Example of X-ray system setting

45. Radiation Protection in Cardiology Lecture 4: Angiography equipment45 APR Philips Integris H5000 Room 3, December 2001 Fluo lowFluo medFluo high

46. International Atomic Energy Agency IAEA survey 2001-2003 X-ray systems evaluated: 9-15 from 5 countries

47. Radiation Protection in Cardiology Lecture 4: Angiography equipment47 Very different dose/frame values have been found

48. Radiation Protection in Cardiology Lecture 4: Angiography equipment48 Also different dose increase with patient thickness

49. Radiation Protection in Cardiology Lecture 4: Angiography equipment49 Also different dose increase with fluoroscopy modes

50. Radiation Protection in Cardiology Lecture 4: Angiography equipment50 Conclusions from the IAEA survey Patient dose and image quality depend largely on the settings made at the commissioning of the radiological equipment. For different systems and different operation modes, entrance air kerma can increase by a factor of 20 (including electronic magnification) for the same patient thickness.

51. Radiation Protection in Cardiology Lecture 4: Angiography equipment51 Increasing phantom thickness increases dose by an additional factor of up to 12. Differences in radiation doses from the evaluated systems show a potential for dose reduction whilst maintaining image quality. Conclusions from the IAEA survey

52. Radiation Protection in Cardiology Lecture 4: Angiography equipment52 Importance of testing X ray equipment Characterization of the X- ray system, that should be part of the acceptance and status tests, should inform cardiologists about the dose rates and dose/frame for the different operation modes and for the different patient thicknesses. Image quality shall also be evaluated. Regular constancy checks should verify if important changes could been occurred.

53. International Atomic Energy Agency Examples of patient dose reports

54. Radiation Protection in Cardiology Lecture 4: Angiography equipment54 Example of the data included in the study report (Siemens)

55. Radiation Protection in Cardiology Lecture 4: Angiography equipment55 Example of the data included in the dosimetric report (Philips): Philips Integris 5000: Coronary angiography 65% cine; 35% fluoroscopy 13 series, 728 frames 1,54 Gy.cm 2 /min 0,368 Gy.cm 2 /10 fr 1 min fluoroscopy = 39 fr = 3 s cine

56. International Atomic Energy Agency Examples of information contained at the DICOM header

57. Radiation Protection in Cardiology Lecture 4: Angiography equipment57

58. Radiation Protection in Cardiology Lecture 4: Angiography equipment58

59. Radiation Protection in Cardiology Lecture 4: Angiography equipment59

60. Radiation Protection in Cardiology Lecture 4: Angiography equipment60Summary What to look for while establishing a cath lab FDA, IEC, ACR recommendations Specific aspects in paediatrics Examples of patient dose reports Dose variation in cine & fluoro- IAEA survey DICOM header information