Shielding design for interventinal procedure, by Gary ...
The Value of Composite Protective
Shields in Exposure Reduction
During Interventional Procedure
Gary D. Hartwell, David J. Spinosa*, Allen R. Goode,
John F. Angle, Alan H. Matsumoto
Divisions of Medical Physics and Interventional
University of Virginia Health System, Charlottesville,
* Inova Fairfax Hospital Falls Church, Va.
Many fluoroscopically guided interventional
procedures require high exposure.
Benefits to patients far outweigh the risks.
Patients are often large.
Require long fluoroscopic times.
Can result in potentially serious long term
consequences for the physicians who perform
Over a career the risks to the physician not
mitigated by a corresponding benefit.
Left and Right Locations → Collar, Waist and Knee
(Total 6 DMs)
INSIDE LEAD: 0.5 mm equivalent
Left and Right Locations → Waist
1 DM was placed outside the angiographic
Procedures Types and
IRs performed 176 Diagnostic and Interventional
Procedures over a 7 Month Period:
28 GU/biliary including TIPS
Procedures Performed by side of Table→
The Median Radiation Exposure to the
Waist and Collar Locations →
(Rt, p<0.0001; Lt, p<0.0001)
Lead Apron →
Reduced Radiation Exposure at the
Waist Location by 97.7% (p<0.0001)
Maximun Exposure (mR)
per Procedure by Location
Rt Col: 131 Lt Col: 245
Rt W: 3037 Lt W: 1795
Rt K: 1218 Lt K: 1174
Rt W (I): 93 Lt W (I): 20
Fluoroscopic Entrance Skin
1995 median patient thickness 21.5 cM
1995 median ESE 1250 mR min-1
2005 median patient thickness 23.5 cM
2005 median ESE 750 mR min-1
available are very
awkward to position
where they will be
Tricky to maintain the
Composite protective shields
Do Recently introduced Composite protective
shields provide shielding from scatter
radiation while maintaining the integrity of
the sterile field?
Evaluate how effectively these shields reduce
exposure to the physician.
Ease of use while maintaining sterile field.
Ease of deployment for different procedure
Angiographic table was located 110 cm above
X-ray tube under the table.
Dosimeter was fixed at different heights on a
tripod 1 meter from the point where the beam
intersected the phantom.
Exposure measurements were made and
recorded without and with combinations of the
composite shields in place.
Maximum Exposure Rate
Radiation Measurements while operating at the maximum
exposure rate were also made at the 0 degrees position
in order to:
Confirm performance of the shields at the high
exposure rates and increased scatter radiation that
would be expected from large patients.
Evaluate how well the composite shields performed at
the higher beam energy.
Maximum Exposure Results
9.7 R per minute exposure rate.
Exposure at chest height without shields 12 mR
Exposure at chest height with shields 1.9 mR per
More than 6 times average patient rate
Greater when HLC used.
Is there a size patient who should be be
denied an elective procedure because of
poor image quality and excessive dose
to the physician?
Shields can be very effective >80%
Composite shields were equally effective at all
Shields must be used in combination
Must be placed in the optimum location.