The interventional cardiology team who gets the most exposure in percutaneous recanalisation of chronic total occlusion (CTO) procedures?

Transcription

1 The interventional cardiology team who gets the most exposure in percutaneous recanalisation of chronic total occlusion (CTO) procedures? L. Price, A. Pascoal Proteção Radiológica na Saúde, Sep 2013, Lisbon Portugal

2 Outline Background Aims Material & Methods Results Discussion Conclusions Final considerations 2

3 Background Chronic Total Occlusion (CTO) Total blockage ( 99% stenosis) of a coronary artery Lasts a long time (> 3 months) and/or continually recurrent Shows with poor or forward (antegrade) blood flow [1]. [1] Soten et al, Part I, Circulation 2005 [2] British cardiac patient association 3

4 Background Chronic Total Occlusion (CTO) Hard plaque Fibrocalcification > 50% Collagen/Calcium Soft plaque > 50% cholesterol Macrophages Loose fibrous tissue 4

5 Background Recanalisation of Chronic Total Occlusion (CTO) A type of percutaneous coronary intervention (PCI) which is a treatment option for CTO Represent % of percutaneous coronary interventions (PCI) at selected centres [3] Soten et al, Part II, Circulation

6 Background Percutaneous Recanalisation of CTOs Technically very challenging and time consuming (1-3h ) Staff and patient exposure to X-ray Performed in cardiac labs under X-ray image guidance (to drive catheters and guide wires) with the patient under local aesthetic multiple fluoroscopic projections 6

7 Background Percutaneous Recanalisation of CTOs at KCH Interventional cardiology team Cardiologists Nurses (scrub, run ) Radiographer Physiologist Visiting staff (observers) 7

8 Aims of the study Measure scatter dose for different staff roles over 16 PCI CTO recanalization procedures performed by experienced cardiologists Measure scatter dose to non-protected tissue Compare scatter dose for various staff roles Investigate how individual practice affects dose Investigate the suitability of a new active dosemeter system to support optimisation of radiation protection during interventional cardiology procedures 8

9 Equipment & Methods Staff monitored Primary cardiologist Secondary cardiologist Visiting cardiologist (primary, secondary and observer) Scrub nurse Run nurse Radiographer The physiologist and physicist were in the control room and were not monitored. 9

10 Equipment & Methods Staff monitored Positioning in the room 10

11 Equipment & Methods Materials & Methods Fluoroscopy system (C-arm) Active dosemeter system (Raysafe i2) Solid-state Measures personal dose equivalent (Hp (10)) Stores and transmits wirelessly in real time (every sec) to a remote base station (displays dose data as colour coded bars) Doses can be exported for analysis with i2 software The manufacturer claim the system is calibrated (certificate traceable to primary standard) 11

12 Equipment & Methods Materials & Methods The system response was tested in our lab (by our colleagues) The idose provides reliable and reproducible results for kvp up to 70 kv and < 10 ma Above 70 and up to 90kVp differences were noticed between the response of a few dosemeters but not for the majority. The difference between the sensors and the ion chamber was higher at higher dose rates. 12

13 Equipment & Methods Positioning of the radiation badges Staff: over the lead coat at chest height to measure scatter dose no unprotected organs 13

14 Equipment & Methods Positioning of the radiation badges Reference position: on the C-arm (45º from isocenter) (assess dose to non-protected tissue in the absence of \ protective measures ) 14

15 Equipment & Methods 16 CTO procedures performed over 4 days at the cardiac lab, King s College Hospital Data collected Cumulative staff dose (Hp(10); µsv) Dose rate (Hp(10); µsv/h) Staff positioning and individual practice for each role Fluoroscopy procedure data DAP Total fluoro time Patient details (age, height, weight) 15

16 Equipment & Methods CTO recanalisation cases - summary CTO case Dose ref point (msv) Fluoro time (min) DAP (Gy/cm2) BMI (kg/m 2 )

17 Results Scatter dose at reference position (C-arm) (represents scatter dose in the absense of protective measures) 17

18 Results Effectiveness of radiation protection measures Cumulative dose for primary radiologist and at the reference point (illustrates dose to unshielded organs and effect of protection measures). ( msv) ( msv) Results in agreement with Vano et al, Card Interv Rad,

19 Results Total accumulated staff dose over all procedures (for which the member of staff was present) Why? Why? 19

20 Results we checked our notes 20

21 Results the observer cardiologist moved to a position in front of the ceiling suspended screen (to get better visibility of the images displayed in the monitors) and stood next to the C-Arm head for a total accumulated time of 1h 21

22 Cardiac lab layout monitors monitors 22

23 Results Sub-optimum practice of (observer) cardiologist For 1/3 of the procedure duration the observer cardiologist received higher dose rate than the reference point. 23

24 Results what about the nurse? She was the run nurse and was positioned further away from the patient table. 24

25 Results we checked our notes again 25

26 Results the patient became agitated and started moving; the run nurse moved to the side of the table to calm him down and stood right close to the C-Arm head for a few minutes 26

27 Cardiac lab layout 27

28 Results Total accumulated staff dose over all procedures (for which the member of staff was present) 28

29 Conclusions The visiting cardiologist received the largest exposure over the complete set of 16 procedures visitors should be made aware of radiation protection measures optimisation of the room layout and staff positioning is essential The run nurse received higher dose compared to other nurse staff when assisted a patient Improve shielding (should wear protective glasses?) Staff training should address also unusual scenarios 29

30 Final considerations Barrier radiation protection measures (e.g. ceiling suspended lead shielding, lead skirt at the patient table) effectively contribute to reduce staff dose due to scatter radiation and must be used adequately Real-time dose monitoring effectively helps investigating staff exposure and provides useful input to optimise radiation protection practice in interventional procedures Raysafe i2 dosemeter showed as a useful tool to be used in staff training and routinely in interventional procedures to reduce personnel radiation dose. Calibration traceable to a standard should be considering when using the system for absolute dose measurements. 30

31 Acknowledgments Many thanks to Mr Lee Evans and Mr Bart Lecou at Raysafe (Unfors Raysafe Ltd) for the loan of the idose equipment. Dr James Sapontis, Dr Johnathan Hill and Mr Greg Cruickshank and all members of the IC team for collaborating in the data collection at King s College Hospital, London. 31

32 Acknowledgments Thank you Comments and questions (in English or Portuguese) are most welcome) 32