Secondary Risks in Radiation Protection in Interventional Cardiology and Radiology:

Solving one problem without creating another

Paddy Gilligan, Dublin, Ireland

Disclosures

• Mavig

• Mater Private Group

Occupational Radiation Dose

• Modern interventional units have become more powerful allowing more complex lengthy procedures. Higher staff doses

• Radial techniques allow greater throughput and quicker recovery

Higher staff doses • Radiation Dose Limit to the eyes has lowered by

a factor of 7 under new EU directive (59/13) -clinical workload restrictions by 2018 ?

y = 0,0856x + 0,0193 R² = 0,832

0

2

4

6

8

10

12

14

0 20 40 60 80 100 120 140 160

LHS

Co

llar

Do

se (

mSv

)

Total # procedures in a given month

Collar TLD Dose/ Month vs Activity

Cardiologist Workload 2015

Solutions • Do less procedures

– Patient suffers, poor access to clinical procedures increased waiting lists

Solutions • Replace existing technology & Equipment

with better dose performance equipment – Capital investment, Equipment life cycle ,lower

radiation dose and clinical performance

Dose Reduction • Increase protection in lead aprons:

- extra weight, lead aprons, increased spinal problems.

• Engineered Solutions

- Zero Gravity ,Catphax: high level of protection with no weight for operator, workflow and capital cost

• Eye Protection

- Lead glasses: compliance & uncertainty over level of protection (dose reduction factor 2-6) .

Aprons Weights and Transmission

Apron Weight Sacttered Transmission % @ weakest point, no copper, 80 KVp

Vendor 1 ,0.25 mm lead free, coat and skirt, thyroid collar

3.75 Kg 9.9 %

Vendor 2 ,0.25 mm lead free, coat and skirt

4.01 Kg 10 %*

Vendor 2,0.25 mm lead free single apron

4.75 Kg 10 %*

Vendor 2 , 0.25 mm lead composite single apron

7 kg 4 %*

http://www.materprivate.ie/

Solutions

• Reduce scatter at source: –Concerns about automatic exposure control

• Lead aprons reduce operator dose but increase dose three fold

– Interference with procedure

– Infection Control Musallam A, et al. A randomized study comparing the use of a pelvic lead shield during trans-radial interventions: Threefold decrease in radiation to the operator but double exposure to the patient. Catheter Cardiovasc Interv. 2015 Jun;85(7):1164-70

Current Shielding Arrangements

• Upper body protection developed for femoral access

• Lower body shield

• Drapes not used locally due to concern over automatic exposure control

Objective:

• To clinically evaluate novel MAVIG shield/ drape combination against a number of end points:

– Staff Dose reduction

– Effect on Patient Dose

– Clinical Utility

– Infection control

Novel Shield from MAVIG, Germany

• 0.5 mm Pb lead acrylic

• Larger with better eye protection

• Clip on lamellae depending on whether access is radial or femoral

Conventional New shield

On-Patient Drape

• 0.5 mm Pb flexible shield

• Designed differently for each access type

• Disposable sterile cover

• Washable material

• Placed under or over cloth/ paper sterile patient drape

• Protective effect was modeled using Monte Carlo simulation

• Modeling results were correlated with Rando Phantom Measurements

• Estimated reduction :

– Shield alone : 84%

– Combined shield and pad: 90%

Eder H, Seidenbusch MC, Treitl M, Gilligan P. A New Design of a Lead-Acrylic Shield for Staff Dose Reduction in Radial and Femoral Access Coronary Catheterization. Rofo. 2015 Jun 17.

Dose Aware

Ray safe dose aware I2 EPD introduced March 2013

Materials and Methods

• Siemens Artis zee large detector interventional System

• Angios, Chronic Total Occlusion, PCI’s

• Data collected in September, October, November 2013

• Shield/ Pad placed in October 2013

• Collected collar EPD exposure per case for Cardiologist, Nurse , Radiographer, Technician

• Excluded where mobile phone was present

• Training and evaluation

• Statistical analysis using Mann Whitney U Test

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10

100

1000

Angio PCI CTO

Pooled Cardiologist Exposure Reading Per Procedure (µSv)

Without Shield

With Shield

OVERALL

No of Procedures Median EPD exposure

in µSv /procedure p

Without With Without With

Cardiologists Pooled

165 132 15.7 7.3 <0.0001

Nurse Pooled 125 133 1 0.1 <0.0001

Tech Pooled 203 137 3.2 2.7 ns

Rad Pooled 177 137 4.2 2.5 <0.0001

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100

1000

Pooled Cardiologist 1 Cardiologist 2 Cardiologist 3

Cardiologist EPD reading per Angiographic Procedure (μSv)

Without Shield

With Shield

OVERALL

No of Procedures Median Dose in µSv

/procedure

p

Without With Without With

Cardiologist 1 23 25 22.2 7.5 0.0164

Cardiologist 2 49 42 13.7 5.05 0.00068

Cardiologist 3 43 20 14.8 12.25 ns

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RRA RFA

Pooled Cardiologist Doses for radial and femoral Access Type (Angio)

Without Shield

With Shield

Discussion

• Shield and drape do reduce exposure to cardiologists by a factor of two to three with reductions for other staff

• Similar exposure reduction equivalent to doubling of lead apron weight

• Reduction similar or better than that reported for drapes alone in the literature

• Operator and procedure effect is significant

Dose reduction achieved with

• No increase in patient dose area product

• No evidence of infection issues

• No interference with clinical workflow

Results Clinical

• Cardiologists found shield easy to use

• Differing approaches to placement of shield and pad

• Sterile covers were tight : scrub issue

Conclusion

“A novel shield/ drape design has led to occupational exposure reduction without increasing patient exposure in interventional cardiology”.

Thank You