9th International Conference & Workshop “Medical Physics
in the Baltic States”, 2011
VERIFICATION OF LEAD EQUIVALENT
FOR PROTECTIVE APRONS USED IN
RADIOLOGY
Neringa VAIČIŪNAITĖ 1, Marius LAURIKAITIS2, Jurgita LAURIKAITIENĖ 2,
Reda ČERAPAITĖ - TRUŠINSKIENĖ2, Gediminas ADLYS1
1 Physics Department, Kaunas University of Technology
2Oncology Hospital, Hospital of Lithuanian University of Health Sciences Kaunas Clinics
Introduction
• Protective aprons are used for a variety of diagnostic imaging
procedures and are designed to shield approximately from 75% to
90% of radiosensitive red bone marrow.
• Body aprons should be available with a protective equivalent of
not less than 0.25 mm lead for X-rays up to 100 kV and not less
than 0.35 mm lead for X-rays over 100 kV.
• Protective clothing worn by radiographers contains lead and often
other metals (e.g., tin, tungsten, antimony, barium).
• These metals are homogeneously mixed with synthetic rubber or
PVC (polyvinyl chloride).
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Purpose
•To verify the lead equivalent for different types of
protective aprons.
•To calculate a shielding effect for protective aprons.
•To investigate the relation between potential of X-ray
generator and the lead equivalent of the aprons.
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Materials
Aprons: 0.3 mm DENTSPLAY RINN
0.35 mm CAWO FLEX
Collars: 0.3 mm for DENTSPLAY RINN
0.5 mm CAWO FLEX
DENTSPLAY RINN apron and collar
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CAWO FLEX apron and collar
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Method
• Products were investigated using
high frequency, one phase and three
phases X-ray generators.
• Different voltages and exposure
areas on the surface of the apron
were chosen.
Schematic view of the dose
measurement method used for Xrays without and under radiation
protection apron.
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• The “Barracuda” (RTI Electronics)
multimeter with Multi-Purpose
Detector was used for kVp
measurements and the “Barracuda”
multimeter with Dose Detector
R100B was used for dose
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measurements.
Method
• Transmission of X-rays B(x):
where air kerma without the apron K(0) and with protective apron
which covers the detector K(x).
• The thickness of lead
equivalent x is calculated:
where , ,  are fitting parameters, dependent on voltage used .
•The shielding effect (SE) of
apron was determined:
where K(0)- dose measurement (mGy) without lead apron, K(x) –
dose
measurement (mGy) with lead apron.
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Results
The thickness (a) and the shielding effect (b) of measured DENTSPLY
RINN apron and collar lead equivalents versus X-ray tube potential
for three different X- ray generators.
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Results
The Pb equivalent thickness (a) and shielding effect (b) of
investigated DENTSPLY RINN and for CAWO FLEX lead aprons and
collars versus X-ray tube potential for high frequency generator.
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Conclusions
• Thickness of the lead equivalent depends on the tube potential
and on the features of lead apron.
•Improving tube potential increases lead equivalent thickness and
decreases shielding effect.
•The lead equivalent thickness indicated by the manufactures is
not always reached. For this reason all new lead aprons need to be
investigated, to ensure adequate personnel shielding from ionizing
radiation.
•The changes in lead equivalent thickness are impossible in nonlead materials of protective aprons during the time.
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Thank You for your attention
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References
1. Finnerty M., Brennan P. C. Protective aprons in imaging departments:
manufacturer stated lead equivalence values require validation. Eur.
Radiol., 15, 2005, p. 1477–1484.
2. Vano E., Gonzalez L., Guibelalde E. Radiation exposure to medical
stuff in interventional cardiac radiology. The British Journal of
Radiology, 71, 1998, p. 954-960.
3. Hubbert T.E., Vucich J.J., Armstrong M.R. Lightweight Aprons for
Protection Against Scattered Radiation During Fluoroscopy. AJR: 161,
1993, p. 1079-1081.
4. NCRP Report 147. Structural Shielding Design for Medical X-Ray
Imaging Facilities. 2004.
5. Zuguchi M., Chidal K., Taura M. Usefulness of non-lead aprons in
radiation protection for physicians performing interventional
procedures. Radiation Protection Dosimetry, 131-4, 2008, p. 531–534.
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