Fetal Organ-level Specific Absorbed Fractions from Maternal Photon Sources Using Pregnant Female Phantoms

Area of Science:

• Medical Physics
• Radiation Dosimetry
• Computational Biology

Background:

• Accurate fetal radiation dose estimation is vital for maternal exposure scenarios.
• Existing dosimetry tools lack the anatomical detail for fetal organ-level risk assessment.

Purpose of the Study:

• To develop a comprehensive dataset of photon specific absorbed fractions (SAFs) for maternal-to-fetal dosimetry.
• To provide detailed fetal organ dosimetry across eight gestational ages (8-38 weeks).

Main Methods:

• Utilized anatomically realistic hybrid pregnant female phantoms with detailed fetal models.
• Calculated SAFs for 70 maternal source and 55 fetal target regions.
• Analyzed chord length distributions to assess maternal-fetal organ spatial relationships.

Main Results:

• SAFs demonstrated strong dependence on anatomical proximity and photon energy.
• Temporal patterns showed SAFs increasing with gestational age from distant sources and decreasing from adjacent sources.
• Organ-specific SAFs varied significantly, highlighting the importance of detailed fetal dosimetry.

Conclusions:

• The developed SAF dataset offers unprecedented anatomical realism and gestational coverage for fetal dosimetry.
• Enhanced accuracy in fetal organ-level dose assessment supports clinical decisions and radiation protection guidelines.
• This work is critical for understanding radiation risks in pregnant populations.