Mesh-based detailed skeletal models for the ICRP reference pediatric individuals: development and dosimetric...

Area of Science:

• Medical Physics
• Radiological Sciences
• Biomedical Engineering

Background:

• The skeleton contains red bone marrow (RBM) and endosteum, crucial for radiation dosimetry due to links with leukemia and bone cancer.
• Existing adult skeletal dosimetry relies on 3D imaging (e.g., µCT), but pediatric dosimetry lags due to a lack of comparable imaging data.

Purpose of the Study:

• To create detailed, 3D image-based pediatric skeletal models for improved radiation dosimetry.
• To incorporate developing pediatric skeleton anatomical features into models derived from adult data.

Main Methods:

• Established target skeletal values from literature and ICRP, including mass and cellularity.
• Refined adult µCT-derived trabecular bone models, added a 50-µm endosteal layer, and defined RBM and yellow bone marrow (YBM) regions.
• Automated all modeling steps using a C++ program.

Main Results:

• Developed 246 high-quality 3D pediatric skeletal models across six age/sex groups (newborn to 15 years).
• Models accurately represent trabecular bone, RBM/YBM, and match target values within 2%.
• Simulations showed specific absorbed fractions increase with decreasing age, influenced by anatomical factors.

Conclusions:

• This work presents the first comprehensive 3D image-based pediatric skeletal models for dosimetry.
• These models and derived dosimetric datasets offer a robust foundation for enhancing pediatric skeletal dosimetry accuracy and reliability.