Radiation Exposure of Operating Theatre Staff during Surgical Operation

Transcription

1 Radiation Exposure of Operating Theatre Staff during Surgical Operation January 2006

2 Introduction: Usage of X-ray fluoroscopy enables surgical operation to be performed with less invasive method. Besides providing a one stop diagnostic screening, fluoroscopy has become an inseparable guide for the majority part of a surgical procedure and therefore the fluoroscopic time has also been increased. Procedures involving X-ray are more and more complicated. The application of X-ray is rapidly increasing in Vascular, Urological and Paediatric surgery specialties. Some of the examples include endovascular aneurysm repair with stent-graft device and peripheral artery angioplasty in vascular surgery, percutaneous nephrolithrotripsy and ureteroscopic procedures in urology, and tracheal and esophageal stenting in paediatric surgery. More than half of the Vascular surgery operations and more than one third of Urology operations required fluoroscopy guidance in Queen Mary hospital in Radiation, however, is well known to have hazardous effect on human beings which is dose related. It can cause cell death resulting in skin changes, hair loss, cataract and marrow suppression. Radiation can also induce cellular transformation resulting in genetic mutation, teratogenesis and carcinogenesis. The risk of hazardous effect is proportional to the amount of radiation absorbed. Therefore dosage of radiation that clinical staffs were exposed during operation should be carefully monitored especially with increasing frequency and duration of radiation exposure. The amount of scattered radiation during operation is decreased exponentially with distance from the radiation source. Surgeons, anaesthetist, nurses and radiographers who need to stand close to the patient during the operation therefore bear the highest risk of radiation hazard. Currently a badge of dosimeter is being carried by all s and scrub nurses involved in operation requiring X-ray at the chest level. The dosage of radiation absorbed will be measured every month. However, this dosimeter only measures the radiation towards the truncal area under lead apron protection (effective radiation absorbed dose) which does not represent the radiation absorbed by other body parts like eyes and limbs. Moreover, s and nurses may forget to wear the dosimeter after changed to theatre uniform, affecting the accuracy of radiation absorption measurement. Thus we need a more comprehensive study of the radiation absorbed by different areas of body of operating theatre staffs over a long period of time to estimate the exact risk they bear in current hospital theatre setting. 1

3 Objectives of the study: This study aimed to 1) Estimate the dosage of radiation absorbed by s, scrub nurses and other theatre staff for fluoroscopy guided Vascular, Urological and Paediatric surgical operations with respect to international safety standard 2) Evaluate the current practice of protection against radiation and to determine the benefit of reducing radiation exposure with various protective devices 2

4 Recommended dosage exposure limitation International Commission on Radiation Protection ICRP had set up a safety dose limit for occupational and public exposure with respect to different body areas as illustrated in the table below Tissue or organ Dose limit for Time period occupational worker Whole body 20mSv/year averaged over 5 years Lens of the eye 150mSv/year In any calendar year Abdomen of reproductive age female worker 5mSv In any consecutive 3 months interval Foetus of pregnant female worker 1mSv During the whole pregnancy period Hospital provided and extra installed radiation protective devices: Queen Mary Hospital operating theatre has installed 0.3mm and 0.5mm lead apron and lead thyroid shield as radiation protective devices for staff operating with the X-ray machine. The radiation protection devices installed in other hospitals in Hong Kong were similar to Queen Mary Hospital. The division of Vascular Surgery had purchased extra protection devices including an operating table for X-ray procedures with extra lead shield on its side (US Imaging Tables, New York, US), mobile lead shields and reflective glove. Individual had purchased lead eyeglasses. Fluoroscopy machine: The fluoroscopy machines in the operating theatre of Queen Mary Hospital providing service before the study started were BV 25 and BV 29 (GE Medical Systems, Utah, US). In January 2004, a new fluoroscopy machine OEC 9800 (GE Medical Systems, Utah, US) was installed. Methods: This study was performed in collaboration with Department of Health. Operation selection: All Vascular, Urological and Paediatric operation requiring X-ray fluoroscopy within a period of 18 months were studied. 3

5 Radiation exposure measurement: The dosage of radiation absorbed was measured by mini-thermoluminescent dosimeters (TLD). One piece of TLD will be attached to the 1) Forehead, just above eye level or within lead eyeglasses 2) Chest level beneath a lead apron, 3) Right or left hand whichever is closer to the Fluoroscopy machine (mini-tld attached inside a ring) of the operating, first assistant, second assistant and scrub nurse during each operation. TLD recorded from chest level beneath the lead apron will represent the effective radiation absorbed dose to the trunk. The forehead TLD will record the amount of radiation diverted to eye. And the hand TLD will be a monitor of any direct beam radiation to hands during procedure. One TLD dosimeter will be attached to patient s body near the screening area to measure patient s radiation exposure. One TLD badge was carried by the Radiographer beneath the lead apron. And another badge was placed on the anaesthetic trolley of the operating theatre to measure the approximate amount of radiation to the anaesthetist and also reflects the field irradiation. The position of individual staff relative to the fluoroscopy machine was also marked. The type of operation, duration of operation, total fluoroscopy time, amount of contrast used were recorded in every operation. Before scrubbing up for the operation, the operating s and nurse will attach the forehead and body TLDs. The mini-tld carried in the ring can be washed during scrubbing and then covered under the sterile glove. During every operation, a set of 3 TLDs will be available for all 5 vascular s and the TLD sets left un-used (because the had not scrub up in that particular operation) will be placed outside the theatre and its radiation absorption reading represent the background environmental radiation. After operation, all the TLDs will be collected and sent to laboratory of Department of Health for measurement of dose of radiation absorbed. A questionnaire on practice of radiation safety and knowledge of radiation hazard was distributed to all s participated in the study. 4

6 Results: OSH Research Report A. Division of Vascular surgery In total, 201 vascular surgery operations under fluoroscopy guidance were recorded including 49 endovascular aortic surgery (EVAR) 68 aortogram/arteriogram 79 angioplasty ± stenting (PTA/S) 5 other procedures Figure 1. Percentage of different types of fluoroscopy guided procedures in Vascular surgery Types of vascular operation others 2% Endovascular aortic surgery 24% Angioplasty 40% Aortogram/ arteriogram 34% Participated s Professor SWK Cheng Dr ACW Ting Dr P Ho Dr J Poon Rotating medical officers SC CT HP JP MO 5

7 Figure 2. The position of operating theatre staff and patient to X-ray machine in Vascular surgery R X ray machine A P Mobile lead shield S SA N A Anesthetist S Chief SA Assistance N Scrub nurse R Radiographer P Patient 6

8 B. Division of Urology Two hundred and one operations were recorded from April 2004 to June 2005 including: 89 retrograde pyelogram (RP) 59 Double J catheter insertion/ reposition (JJ) 21 ureteroscopic lithotripsy (URSL) 16 Percutaneous nephro-lithotripsy (PCNL) 16 other procedures Figure 3. Percentage of different types of fluoroscopy guided procedures in Urology Types of urology operation URSL 10% PCNL 8% Others 8% Retrograde pyelogram 45% JJ catheter insertion/ reposition 29% Participating Urologist: Dr PC Tam PT Dr F Lee FL Dr SM Chu SM Dr YL Leung YL Dr MC Cheung MC Dr B Wong BW Dr KL Ho KL Dr HL Tsu HT 7

9 Figure 4. The position of operating theatre staff and patient to X-ray machine in retrograde pyelogram, double J catheter procedure and Ureteroscopic lithotripsy A P X-ray R S N A Anesthetist S Chief N Scrub nurse R Radiographer P - Patient 8

10 Figure 5. The position of operating theatre staff and patient to X-ray machine in percutaneous nephro-lithotripsy OSH Research Report A P R X-ray S N A Anesthetist S Chief N Scrub nurse R Radiographer P - Patient 9

11 C. Division of Paediatric Surgery A total of 10 operations under fluoroscopy guidance were performed from April 2004 to June endoscopy (bronchoscopy/upper endoscopy) and dilatation 4 paediatric urology procedures Since the number of procedures is small, further analysis was not performed The table below illustrated the summary of the fluoroscopy guidance procedure performed in Paediatric surgery Type of OT OT time (min) FT (min) X ray machine OT table Protective device Urology BV 25 Belmont 5mm lead apron only Endoscopy BV29 Belmont 5mm lead apron only Endoscopy BV29 Belmont 5mm lead apron only Endoscopy BV29 Belmont 5mm lead apron only Urology BV29 Belmont 5mm lead apron only Endoscopy BV25 Belmont 5mm lead apron only Endoscopy BV29 Belmont 5mm lead apron only Endoscopy BV29 Belmont 5mm lead apron only Urology BV29 Belmont 3mm lead apron only Urology BV25 Belmont 5mm lead apron only Body dose of chief (µsv) Eye dose of chief (µsv) Finger dose of chief (µsv)

12 D. Questionnaire on knowledge and practice of irradiation protection Twelve s participated in this study completed and returned the questionnaire. Only half of them would regularly wear dosimeter in theatre for operation involving fluoroscopy and none of them know their dosimeter decoding result. On asking what possible adverse effects can radiation cause to an operator Mentioned in answer (n=12) Carcinogenesis 10/12 Teratogenicity 4/12 Subfertility 10/12 Thyroid dysfunction 4/12 Cataract 4/12 Bone marrow suppression 1/12 Hair loss 2/12 11

13 Table 1. Summary of operative details, protective devices application, field, patient and radiographer radiation absorption for different types of Vascular operations OT Settings OT table EVAR Aortogram/ arteriogram PTA/S Others All operations n = 49 n = 68 n = 79 n = 5 n = % US imaging 2.0% conventional X-ray machine 85.7% OEC % BV % US imaging 4.4% conventional 92.6% OEC % BV % US imaging 8.9% conventional 88.6% OEC % BV29 100% US imaging 0% conventional 80% OEC % BV % US imaging 5.5% conventiona1 89.1% OEC % BV29 Full body lead shield 100% yes 98.5% yes 94.9% yes 100% yes 97.5% yes Half body lead shield 8.2% yes 26.5% yes 13.9% yes 20% yes 16.9% yes Overhead lead shield 4.1% yes 0% yes 2.5% yes 20% yes 2.5% yes Lead shield (anesthetist) 30.6% yes 48.5% yes 38.0% yes 80% yes 40.8% yes Mean OT time (min) ± ± ± ± ± 6.0 Mean FT time (min) 16.2 ± ± ± ± ± 0.5 Cumulative FT time (min) Mean Contrast volume(ml) ± ± ± ± ± 3.3 Field Field cumulative dose(usv) Patient (0 40) (0-40) (0-40) Mean patient dose (msv) 20.2 ± ± ± ± ± 1.5 Radiographer Radiographer cumulative body dose (usv) FT- Fluoroscopy time, OT operation 12

14 The radiation absorption of individual Vascular was analysed and listed as below (Table 2-6): Table 2. Radiation absorption summary of SC EVAR Aortogram/ Arteriogram PTA/S Others All operations No. of operations Lead apron Thyroid shield 100% 0.5mm 100% yes Lead eye glasses 98.0% yes 100% yes 100% yes 100% yes 99.0% yes Reflective glove 12.2% yes 5.9% yes 7.1% yes 0% yes 8.9% yes Role in operations Cumulative body absorbed Cumulative finger absorbed Cumulative eye absorbed 98% chief 2% 1 st assistant (0-110) 150 (0-60) 100% chief 78.6% chief (0-240) % 1 st assistant (0-80) 40 (0-40) 100% chief 96.0% chief 4.0% 1 st assistant (0-50) 2070 (0-240) 260 (0-60) 13

15 Table 3. Radiation absorption summary of CT EVAR Aortogram/ Arteriogram PTA/S Others All operations No. of operations Lead apron Thyroid shield 100% 0.5mm 100% yes Lead eye glasses 16.1% yes 3.1% yes 4.2% yes % yes 7.9% yes Reflective glove 0% yes 0% yes 2.1% yes 0% yes 0.9% yes Role in operations Cumulative body absorbed Cumulative finger absorbed Cumulative eye absorbed 48.4% chief 48.4% 1 st assistant 3.2% 2 nd assistant 240 (0-70) 940 (0-110) 270 (0-40) 71.9% chief 28.1% 1 st assistant (0-60) % chief 4.2% 1 st assistant 2.1% 2 nd assistant 180 (0-60) 1250 (0-280) 160 (0-70) 66.7% chief 33.3% 1 st assistant 74.60% chief 23.6% 1 st assistant 1.8% 2 nd assistant (0-70) 2500 (0-280) (0-70) 14

16 Table 4. Radiation absorption summary of HP EVAR Aortogram/ Arteriogram PTA/S Others All operations No. of operations Lead apron 100% 0.5mm Thyroid shield 100% yes 100% yes 94.7% yes 100% yes 98.1% yes Lead eye glasses Reflective glove Role in operations Cumulative body absorbed Cumulative finger absorbed Cumulative eye absorbed dose (range)/usv 25.8% chief 38.7% 1 st assistant 32.3% 2 nd assistant 3.2% 4 th assistant 80 (0-40) 1180 (0-160) % chief 56.2% 1 st assistant 6.3% 2 nd assistant 110 (0-70) 380 (0-70) 100 0% yes 0% yes 76.3% chief 18.4% 1 st assistant 5.3% 2 nd assistant 100 (0-40) 1050 (0-230) 70 50% chief 50% 1 st assistant 48.5% chief 36.9% 1 st assistant 13.6% 2 nd assistant 1% 4 th assistant (0-70) 2630 (0-230)

17 Table 5. Radiation absorption summary of JP EVAR Aortogram/ Arteriogram PTA/S Others All operations No. of operations Lead apron 100% 0.5mm 100% 0.5mm 2.9% 0.3mm Thyroid shield 97.1% 0.5mm 100% yes 100% 0.5mm 1.1% 0.3mm 98.9% 0.5mm Lead eye glasses 21.4% yes 4.2% yes 5.7% yes 100% yes 11.4% yes Reflective glove Role in operations Cumulative body absorbed Cumulative finger absorbed Cumulative eye absorbed dose (range)/usv 3.6% chief 50.0% 1 st assistant 25.0% 2 nd assistant 21.4% 3 rd assistant % chief 20.8% 1 st assistant 16.7% 2 nd assistant 4.2% 3 rd assistant (0-50) 60 0% yes 65.7% chief 25.7% 1 st assistant 5.7% 2 nd assistant 2.9% 3 rd assistant (0-70) 100% 1 st assistant 43.2% chief 33.0% 1 st assistant 14.8% 2 nd assistant 9.0% 3 rd assistant (0-70)

18 Table 6. Radiation absorption summary of MO EVAR Aortogram/ Arteriogram PTA/S Others All operations No. of operations Lead apron 6.9% 0.3mm 93.1% 0.5mm 100% 0.5mm 100% 0.5mm 100% 0.5mm 1.9% 0.3mm 98.1% 0.5mm Thyroid shield 100% yes 96.9% yes 100% yes 100% yes 99.0% yes Lead eye glasses Reflective glove Role in operations Cumulative body absorbed Cumulative finger absorbed Cumulative eye absorbed dose (range)/usv 3.4% chief 17.2% 1 st assistant 55.2% 2 nd assistant 20.7% 3 rd assistant 3.5% 4 th assistant % chief 43.8% 1 st assistant 34.4% 2 nd assistant 60 0% yes 0% yes 50.0% chief 38.1% 1 st assistant 11.9% 2 nd assistant (0-200) % 1 st assistant 50% 2 nd assistant 27.6% chief 34.3% 1 st assistant 31.4% 2 nd assistant 5.7% 3 rd assistant 1.0% 4 th assistant (0-200)

19 Table 7. Radiation absorption summary of operation scrub nurse EVAR Aortogram/ Arteriogram PTA/S Others All operations No. of operations Lead apron 60.4% 0.3mm 39.6% 0.5mm 49.2% 0.3mm 50.8% 0.5mm 50.0% 0.3mm 50.0% 0.5mm 40% 0.3mm 60% 0.5mm 52.1% 0.3mm 47.9% 0.5mm Thyroid shield 10.4% yes 7.7% yes 5.3% yes 20% yes 7.7% yes Cumulative body absorbed Cumulative finger absorbed Cumulative eye absorbed dose (range)/usv MiniTLDs were not applied to the scrub nurse in 7 operations because of changing of scrub nurse during middle of the procedures The background radiation absorbed measured by unused TLDs ranged from 0 to 40 usv. The range of cumulative body, finger and eye dose of all vascular operations were usv, usv, and usv respectively. 18

20 Table 8. Summary of operative details, protective devices application, field, patient and radiographer radiation absorption for different types of Urology operations RP JJ URSL PCNL Others All operations OT Settings OT table X-ray machine Full body lead shield Half body lead shield Overhead lead shield Lead shield (anesthetist) N = 89 N =59 N = 21 N = 16 N = 16 N = 201 Conventional (Belmont) operation table for all operations BV29 X-ray machine for all operations Not used in all operations Not used in all operations Not used in all operations Not used in all operations Mean OT time (min) 24.9 ± ± ± ± ± ± 2.8 Mean FT time (min) 2.7 ± ± ± ± ± ± 0.2 Cumulative FT time (min) Mean Contrast volume (ml) 14.7 ± ± ± ± ± ± 1.2 Patient Mean patient dose (msv) 2.6 ± ± ± ± ± ± 0.4 Field Cumulative field dose (usv) 340 (0-40) 210 (0-50) 100 (0-50) (0-50) 890 (0-50) Radiographer Cumulative radiographer body dose (usv) 250 (0-50) (0-60) 570 (0-60) 19

21 The radiation absorption of individual Urologist was analysed and listed as below (Table 9-16): Table 9. Radiation absorption summary of HT RP JJ URSL PCNL Others All operations No. of operations Lead apron Thyroid shield Lead eye glass Reflective glove 45.1% 0.3mm 54.9% 0.5mm 56.3% 0.3 mm 43.8% 0.5mm 50% 0.3mm 50% 0.5mm Role in operations 100% chief 100% chief 50% chief Cumulative body absorbed Cumulative finger absorbed Cumulative eye absorbed 480 (0-50) 1980 (0-210) (0-140) 920 (0-100) % 0.3mm 66.7% 0.5mm Not used in all operations Not used in all operations Not used in all operations 50% 1 st assistant % chief 33.3% 1 st assistant (0-320) 0 90 (0-60) 45.5% 0.3mm 54.5% 0.5mm 63.6% chief 36.4% 1 st assistant 50 (0-50) 540 (0-170) % 0.3mm 51.4% 0.5mm 91.4% chief 8.6% 1 st assistant 840 (0-140) 4020 (0-320) 430 (0-60) 20

22 Table 10. Radiation absorption summary of BW RP) JJ URSL PCNL Others All operations No. of operations Lead apron Thyroid shield Lead eye glasses Reflective glove Role in operations Cumulative body absorbed Cumulative finger absorbed dose (range)/ usv Cumulative eye absorbed (0-90) (0-60) 280 (50-280) % 0.5mm 100% yes Not used in all operations Not used in all operations (0-70) % chief ( ) 250 (0-60) (50-90) (0-60) 5210 (0-1140) (0-60) 21

23 Table 11. Radiation absorption summary of SM RP JJ URSL PCNL Others All operations No. of operations Lead apron 100% 0.5mm 100% 0.3 mm 60% 0.3mm 40% 0.5mm 100% 0.3mm 71.4% 0.3mm 28.6% 0.5mm 76.2% 0.3mm 23.8% 0.5mm Thyroid shield 100% Yes 0% Yes 20% Yes 0% Yes 28.6% Yes 19.0% Yes Lead eye glasses Reflective glove Not used in all operations Not used in all operations Role in operations 100% chief 100% chief 100% chief 83.3% chief Cumulative body absorbed Cumulative finger absorbed dose (range)/ usv Cumulative eye absorbed (90-100) % 1 st assistant (20-460) 0 80 (0-60) 100% chief 95.2% chief (0-130) 4.8% 1 st assistant (0-460) (0-60) 22

24 Table 12. Radiation absorption summary of MC RP JJ URSL PCNL Others All operations No. of operations Lead apron 100% 0.5mm Thyroid shield 16.7% Yes 0% Yes 0% Yes 0% Yes 0% Yes 10.3% Yes Lead eye glasses Reflective glove Not used in all operations Not used in all operations Role in operations 100% chief 100% chief 100% chief 100% chief 100% chief 100% chief Cumulative body absorbed Cumulative finger absorbed dose (range)/ usv Cumulative eye absorbed (0-140) (0-80) ( ) 260 (50-140) (0-1460) (0-140) 23

25 Table 13. Radiation absorption summary of KL RP JJ PCNL Others All operations No. of operations Lead apron 100% 0.3mm 83.3% 0.3 mm 16.7% 0.5mm 100% 0.5mm 100% 0.3mm 94.1% 0.3mm 5.9% 0.5mm Thyroid shield 66.7% Yes 66.7% Yes 0% Yes 100% Yes 64.7% Yes Lead eye glasses Reflective glove Role in operations Cumulative body absorbed Cumulative finger absorbed Cumulative eye absorbed (0-120) 130 (0-90) 0 20 Not used in all operations Not used in all operations 100% chief (0-120)

26 Table 14. Radiation absorption summary of PT RP URSL All operations No. of operations Lead apron 100% 0.5mm 100% 0.5mm 100% 0.5mm Thyroid shield Lead eye glasses Reflective glove Role in operations Cumulative body absorbed Cumulative finger absorbed dose (range)/ usv Cumulative eye absorbed % Yes Not used in all operations Not used in all operations 100% chief Table 15. Radiation absorption summary of FL PCNL All operations No. of operations 1 1 Lead apron 100% 0.5mm 100% 0.5mm Thyroid shield 100% No 100% No Lead eye glasses 100% No 100% No Reflective glove 100% No 100% No Role in operations 100% 1 st assistant 100% 1 st assistant Cumulative body absorbed Cumulative finger absorbed Cumulative eye absorbed 0 0 Table 16. Radiation absorption summary of YL URSL All operations No. of operations 1 1 Lead apron 100% 0.5mm 100% 0.5mm Thyroid shield 100% Yes 100% Yes Lead eye glasses 100% No 100% No Reflective glove 100% No 100% No Role in operations 100% chief 100% chief Cumulative body absorbed 0 0 Cumulative finger absorbed Cumulative eye absorbed

27 Table 17. Radiation absorption summary of operation scrub nurse RP JJ URSL PCNL Others All operations No. of operations Lead apron 48.3% 0.3mm 51.7% 0.5mm 52.5% 0.3mm 47.5% 0.5mm 52.4% 0.3mm 47.6% 0.5mm 50% 0.3mm 50% 0.5mm 50% 0.3mm 50% 0.5mm 50.2% 0.3mm 49.8% 0.5mm Thyroid shield 3.4% Yes 0% Yes 0% Yes 6.3% Yes 0% Yes 2.0% Yes Cumulative body absorbed Cumulative finger absorbed dose (range)/ usv Cumulative eye absorbed 280 (0-40) (0-40) (0-50) 260 (0-50) 110 (0-40) (0-40) 740 (0-50) (0-50) 26

28 Table 18. Cumulative fluoroscopy time and cumulative radiation exposure of s, nurses, radiographers and field in Vascular surgery No. of OT % as chief Cumulative fluoroscopy time (min) Cumulative body dose (usv) Cumulative eye dose (usv) Cumulative hand dose (usv) SC CT HP JP MO Nurse Radiographer Field not applicable Remarks: Both supervisor and chief were considered as chief of surgery, therefore more than one chief were present in some of the operations. Table 19. Comparison of absorbed dose per minute fluoroscopy between Vascular s operating as chief No. of operations as chief Cumulative FT time (min) Body dose per minute FT (usv/min) Eye dose per minute FT (usv/min) Hand dose per minute FT (usv/min) SC CT HP JP MO Table 20. Comparison of body absorbed dose per minute fluoroscopy for different groups of procedures for Vascular s Body dose per minute FT for EVAR as chief Body dose per minute FT for EVAR as Body per minute FT for arteriogram as chief Body dose per minute FT for arteriogram as Body dose per minute FT for PTA/S as chief Body dose per minute FT for PTA/S as SC CT HP JP MO not applicable 27

29 Table 21. Comparison of eye absorbed dose per minute fluoroscopy for different groups of procedures for Vascular s Eye dose per minute FT for EVAR as chief Eye dose per minute FT for EVAR as Eye dose per minute FT for arteriogram as chief Eye dose per minute FT for arteriogram as Eye dose per minute FT for PTA/S as chief Eye dose per minute FT for PTA/S as SC CT HP JP MO not applicable Table 22. Comparison of hand absorbed dose per minute fluoroscopy for different groups of procedures for Vascular s Hand dose per minute FT for EVAR as chief Hand dose per minute FT for EVAR as Hand dose per minute FT for arteriogram as chief Hand dose per minute FT for arteriogram as Hand dose per minute FT for PTA/S as chief Hand dose per minute FT for PTA/S as SC CT HP JP MO not applicable 28

30 Table 23. Cumulative fluoroscopy time and cumulative radiation exposure of s, nurses, radiographers and field in Urological operation No. of OT % as chief Cumulative fluoroscopy time (min) Cumulative body dose (usv) Cumulative eye dose (usv) Cumulative hand dose (usv) HT BW SM MC KH PT FL YL Nurse Radiographer Field not applicable Table 24. Comparison of absorbed dose per minute fluoroscopy between Urologists operating as chief No. of operations as chief Cumulative FT time (min) Body dose per minute FT (usv/min) Eye dose per minute FT (usv/min) Hand dose per minute FT (usv/min) HT BW SM MC KL PT

31 Table 25. Comparison of body absorbed dose per minute fluoroscopy for different groups of procedures for Urologists Body dose / minute FT for RP as chief Body dose / minute FT for RP as Body dose / minute FT for JJ as chief Body dose / minute FT for JJ as Body dose / minute FT for URSL as chief Body dose per minute FT for URSL as Body dose / minute FT for PCNL as chief Body dose / minute FT for PCNL as HT BW SM MC KL PT FL YL not applicable Table 26. Comparison of eye absorbed dose per minute fluoroscopy for different groups of procedures for Urologists Eye dose / minute FT for RP as chief Eye dose / minute FT for RP as Eye dose / minute FT for JJ as chief Eye dose / minute FT for JJ as Eye dose / minute FT for URSL as chief Eye dose per minute FT for URSL as Eye dose / minute FT for PCNL as chief Eye dose / minute FT for PCNL as HT BW SM MC KL PT FL YL not applicable 30

32 Table 27. Comparison of hand absorbed dose per minute fluoroscopy for different groups of procedures for Urologists Hand dose / minute FT for RP as chief Hand dose / minute FT for RP as Hand dose / minute FT for JJ as chief Hand dose / minute FT for JJ as Hand dose / minute FT for URSL as chief Hand dose per minute FT for URSL as Hand dose / minute FT for PCNL as chief Hand dose / minute FT for PCNL as HT BW SM MC KL PT FL YL not applicable Table 28. Average chief radiation absorbed dose analysis for Vascular and Urologist Absorbed dose per minute fluoroscopy (usv/min) Body Eye Hand Vascular Urology Table 29. Eye dose analysis of vascular with or without lead eye glasses (Including cases which studied as chief operator in the procedure only) Percentage of lead eye glasses use Eye dose /min fluoroscopy (usv/min) SC CT PH JP MO 99.0% 7.1% 0% 5.3% 0%

33 Table 30. Patient s radiation absorbed dose analysis Fluoroscopy time (min) Mean vascular patient absorbed dose (msv) Mean urology patient absorbed dose (msv) < ± ± ± ± ± ± ± ±

34 Discussions: The absorbed radiation of all participated s, nurses and radiographers was under the limit recommended by the ICRP. Therefore even with frequent use of fluoroscopy in Vascular surgery and Urology, operating theatre staff were still safe with current protective devices in operating theatre. As the chief usually stay at the closest distance to the operative site and X-ray machine, the cumulative radiation absorption was much higher for s compared to scrub nurses and radiograpghers. As a life time career, the less radiation absorbed the better for health of a medical professional. Thus we would like to look for any possible ways to further cut down the radiation absorption of theatre staff especially s. When we compared the cumulative body, eye and finger absorbed dose of s of the same specialty performing same group of operation (Table 20-22, 25-27), there is a difference in radiation absorption between different s. In Urology, a difference of 8.19µSv/min body dose per minute fluoroscopy for URSL was observed comparing the highest (8.33µSv/min) and lowest (0µSv/min) value. Further analysis showed that the body dose was markedly high (140µSv) for a single URSL operation for SM. We suspected that this may be due to improper wearing of the lead apron or there was breakage inside the apron. Beside the individual operation with outranged body absorbed dose, the average urologists body absorbed dose per minute fluoroscopy for all operations was 8.8µSv/min and was about 5 times the level of Vascular s (Table 28). We believe this was related to the high percentage of Urologists wearing 0.3mm lead apron compared to nearly 100% wearing 0.5mm lead apron for Vascular surgery division. Among the Vascular s, the difference in finger dose per minute fluoroscopy was 5.53µSv/min ( µSv/min) for EVAR and 5.17 µsv/min ( µsv/min) for arteriogram. This may be related to the difference in practice of individual s especially where they placed their hands while handling the endovascular catheters and guidewire under the fluoroscopy machine. And whether the will step back while taking a fluoroscopy. The average eye and finger absorbed dose per minute fluoroscopy of Urologists were much higher than 33

35 that of Vascular s (Table 28). The discrepancy may result from the difference in s position in relation to the fluoroscopy machine. Or this may be due to difference in practice of applying radiation protective devices. Mobile full body lead shield was applied in 97.5% Vascular surgery operations and US imaging table was used in 94.5% Vascular procedures, whereas no extra lead shield or special imaging table was applied in any of the Urology operation. The merit of using mobile lead shields is that they can effectively shield off scattered radiation and do not add extraweight to the operating staff. Among the 4 groups of operation of Urology, the average eye and finger absorbed dose for Urologists were the highest in PCNL. This may be related to the close proximity of the operator and the fluoroscopy machine. The distance between and the machine will significantly affect the radiation exposure of the during operation. Besides the aim to minimize radiation exposure of operating theatre staff, we must also take into account the health hazard of applying heavy gear of radiation protective devices. The 0.5mm lead apron usually weighed about 4kg whereas the 0.3mm ones are around 2.5kg. Understanding the approximate radiation exposure in different types of operation could provide information for s to decide between reducing radiation absorption and reducing heavy weight bear during operation, and choose the appropriate protective devices. In the Vascular surgery division, one (SC) wear lead eye glasses in 99% of cases and the other two s apply it occasionally (<10%). One and the rotating medical officers do not apply lead eye glasses at all. When comparing their eye dose per minute fluoroscopy as chief, there is only a small difference noted. Thus, the protective effect of lead eye glasses probably could be replaced by the usage of mobile lead shield as well as stepping away during actual fluoroscopy emission. The amount of radiation absorption of patients increased with increased fluoroscopy time. Under normal circumstances, patients are unlikely to have repeated fluoroscopy guidance procedures within a short period of time and thus the harmful effect would not be significant. However, in case frequent long fluoroscopy guided procedures are indicated, patients should be protected with lead 34

36 shield over other parts of body outside the screening area to minimize radiation hazard imposed to them. According to the results of the questionnaire, the awareness of s to radiation hazard was inadequate. Many of them had not adhered strictly to the way of monitor their radiation absorption. More educational program and propaganda on this issue may help remind hospital staff to be aware of radiation hazard and safety precautions. Apart from protection devices, there are some methods to reduce radiation generated from the fluoroscopy machine. Modern fluoroscopy machines will automatically adjust the amount of radiation generated according to the averaged density of material the radiation got through. Avoiding any metal parts within the fluoroscopy field will minimize the amount of radiation generated. Adjusting collimator size of the fluoroscopy machine or closing down the iris of it will also reduce the amount of radiation generated. Moreover, when the emission tube was tilted, the scattered radiation may increase towards the tilted side. Hospital staff should avoid standing closed to the tilted side of the fluoroscopy. 35

37 Conclusions: 1. Operating theatre staff working on fluoroscopy guided operations are safe with current protective device in the hospital theatre 2. The amount of radiation absorption can be further reduced with additional lead shield. 3. The amount of radiation absorption especially for finger and eye varies with different practice of s during the procedure. 4. Some surgical procedures in which need to operate close to the fluoroscopy machine may absorb greater amount of radiation and more radiation protection devices will be indicated mm lead apron will shield off more radiation compared to 0.3mm one. 6. Patient will bear higher radiation exposure with increased fluoroscopy time of the procedure. 36

38 Recommendations: 1. Additional mobile lead shield and special X-ray imaging table (with side lead shield) is indicated for s who has a high volume fluoroscopy guided operations. 2. The decision on the modality and degree of radiation protection to apply should be individualized according to the expected amount of radiation absorbed for a particular procedure. 3. Surgeons should avoid putting their hands near or over fluoroscopy screening area and keep a distance from the emission tube while taking fluoroscopy as much as possible during the procedure. 4. More educational program and propaganda is indicated for hospital staff operating with fluoroscopy machine to increase their awareness to radiation safety. 5. Consider lead shield for non-operative area of patient if frequent long fluoroscopy procedures is indicated. 37

39 Acknowledgment Operation theatre : Ms Ada Ko, Ms Winnie Chan Urology division : Dr PC Tam, Dr F Lee, Dr Simon Chu, Dr MC Cheung, Dr B Wong, Dr KL Ho, Dr HL Tsu Vascular surgery division: Dr J Poon, Dr KC Ng, Dr WK Yiu, Dr TT Cheung, Ms Silvana Lau, Ms Grace Cheung All radiographers participated in surgical operations 38