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Department of Medical Physics , University Hospital of Heraklion, Crete http://medicalphysics.med.uoc.gr. How to estimate conceptus dose from radiographic, fluoroscopic and fluoroscopically guided interventional procedures. Georgia Solomou, Medical Physicist MSc.
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Department of Medical Physics, University Hospital of Heraklion, Crete http://medicalphysics.med.uoc.gr How to estimate conceptus dose from radiographic, fluoroscopic and fluoroscopically guided interventional procedures Georgia Solomou, Medical Physicist MSc 8th ECMP, 11-13 September 2014, Athens
Contents • When a detailed dose assessment is needed • Available tools to estimate conceptus radiation dose • CONCERT Project • Conclusion
Radiation and pregnancy • Thousands of pregnant women are exposed to ionizing radiation • Lack of knowledge may lead to unnecessary termination of pregnancies • “No safe level” is a sweeping statement • Radiation exposure should be medically appropriate
Is a detailed dose assessment always needed? • No if: • gestational age less than 2 weeks • conceptus dose is low (conceptus is located out of the primary beam)
But when a detail assessment of conceptus radiation dose is needed? Conceptus Dose(mGy) 10 mGy 50 mGy 100 mGy • ICRP publication 84: • Conceptus dose estimation • Dose> 10 mGy TERMINATION of pregnancy at conceptus doses of less than 100 mGy is not justified based upon radiation risk.
When 10 mGy is exceeded? Dauer et al, JVIR, 2012
Which are the available tools for a detailed dose assessment?
Dosimeters - Patient models TLD MOSFET
Monte Carlo Simulation • A general purpose, three-dimensional general geometry, time-dependent, coupled neutron-photon-electron code • It is supported, on a variety of platforms including personal computers. • It has been widely used for medical physics applications • Input file: energy spectra, geometry, mathematical phantoms, materials and tallies. • Mathematical anthropomorphic phantoms are generated using BODYBUILDER software (White Rock Science, White Rock, NM).
… Monte Carlo • Output: Normalized conceptus dose /reference dose
PCXMC- Dose Calculation • Only at the first postconception weeks PCXMC 2.0, STUK-TR 7, Radiation and Nuclear Safety authority, 2012
How can we estimate conceptus dose in every day clinical practice?
AP, PA Chest projections • Dc= f (AP thickness) • 1st trimester • 2nd trimester • 3rd trimester Damilakis et al, Eur. Radiol, 2003
Limitations The existing studies do not include: • All performed projections • The depth of the conceptus at the first trimester, • All radiological examinations • Especially in fluoroscopically guided interventional procedures the existing studies are limited
Conceptus Dose Estimation by radiological examinations • Risks for fatal childhood cancer estimation
Abdomen radiography Pregnant patient at the 1st trimester of gestation How conceptus dose was estimated? • Output =0.055mGy/mAs (FSD=100cm, 80kV)
DFETUS= Σ (ESDI*NFDI) 0.454
Barium Enema Pregnant patient at the 1st trimester of gestation How conceptus dose was estimated? • Output =0.055mGy/mAs (FSD=100cm, 80kV)
Vena Cava filter placement Pregnant patient at the 2nd trimester of gestation How conceptus dose was estimated? • Output =11.412 mGy/(mAs×min) (FSD=100cm, 110kV)
Conceptus Radiogenic Risk Barium Enema 0.49% 0.12% Vena Cava Filter Placement 1 0.8 0.6 Possibility of childhood cancer % 0.4 0.2 0.07% 0 0 20 40 60 80 100 120 Conceptus Dose ( mGy) Dauer et al, JVIR, 2012, McCollough , Radiographics 2007
Conclusion • Conceptus doses from extra-abdominal procedures are low. Conceptus risk is negligible compared to the benefit for the mother. • A detailed dose assessment is needed in examinations where conceptus is irradiated primarily. • Each physicist has the tools to estimate conceptus radiation dose and the associated radiogenic risk.