Fetal dose assessment from invasive special procedures by Monte Carlo methods

Area of Science:

• Medical Physics
• Radiological Sciences
• Radiation Dosimetry

Background:

• Assessing fetal radiation dose in clinical settings is complex due to variations in patient anatomy, imaging techniques, and scatter radiation.
• Accurate fetal dose estimation is crucial for patient safety during diagnostic imaging procedures.

Purpose of the Study:

• To develop and validate a reliable method for estimating fetal radiation dose during special medical procedures.
• To enable rapid and accurate dose assessment for optimizing imaging protocols and minimizing fetal exposure.

Main Methods:

• Utilized template-based input files for the Monte Carlo N-Particle (MCNP) radiation transport code.
• Employed female patient phantoms at various gestational ages (0-9 months) and common diagnostic X-ray source terms.
• Verified geometry and beam locations using 3D visualization software (Sabrina) and MCNP simulations.
• Validated MCNP-derived fetal dose estimates against measured skin entrance exposure (ESE) ratios.

Main Results:

• The MCNP-based method allows for rapid creation of input files for diverse patient anatomies and imaging scenarios.
• Fetal dose estimates can be obtained within one day for most procedures.
• The method accurately determines fetal dose by correlating simulated results with measured skin entrance exposure.

Conclusions:

• This Monte Carlo simulation approach offers a reliable and efficient method for estimating fetal radiation dose.
• The technique facilitates prospective modeling to select imaging parameters that minimize fetal dose.
• The developed method enhances radiation safety for pregnant patients undergoing diagnostic imaging.