Georgia Solomou, Medical Physicist MSc

1. 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

2. Contents • When a detailed dose assessment is needed • Available tools to estimate conceptus radiation dose • CONCERT Project • Conclusion

3. 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

4. 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)

5. 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.

6. When 10 mGy is exceeded?

7. When 10 mGy is exceeded? Dauer et al, JVIR, 2012

8. Which are the available tools for a detailed dose assessment?

9. Dosimeters - Patient models TLD MOSFET

10. 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).

11. … Monte Carlo • Output: Normalized conceptus dose /reference dose

12. PCXMC- Dose Calculation • Only at the first postconception weeks PCXMC 2.0, STUK-TR 7, Radiation and Nuclear Safety authority, 2012

13. How can we estimate conceptus dose in every day clinical practice?

16. AP, PA Chest projections • Dc= f (AP thickness) • 1st trimester • 2nd trimester • 3rd trimester Damilakis et al, Eur. Radiol, 2003

17. 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

18. Conceptus Dose Estimation by radiological examinations • Risks for fatal childhood cancer estimation

20. Abdomen radiography Pregnant patient at the 1st trimester of gestation How conceptus dose was estimated? • Output =0.055mGy/mAs (FSD=100cm, 80kV)

21. DFETUS= Σ (ESDI*NFDI) 0.454

23. Barium Enema Pregnant patient at the 1st trimester of gestation How conceptus dose was estimated? • Output =0.055mGy/mAs (FSD=100cm, 80kV)

24. Dfetus=5cGy

26. 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)

27. Dfetus= 4mGy

28. 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

29. 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.