A physiological skeletal model for radionuclide and stable element biokinetics in children and adults

Area of Science:

• Biophysics
• Radiological Science
• Toxicology

Background:

• Existing skeletal models lack anatomical and physiological accuracy.
• Modeling skeletal uptake and clearance of bone-seeking contaminants is crucial for risk assessment.

Purpose of the Study:

• To describe a novel physiological skeletal model (PSM).
• To accurately represent skeletal uptake, retention, and clearance of radionuclides and elements.
• To account for age-dependent differences in bone turnover, particularly in children.

Main Methods:

• Developed a compartmental model incorporating organic and inorganic bone material.
• Included quiescent bone surfaces, forming bone surfaces, and the lacuno-canaliculi system.
• Incorporated a tertiary mineralization phase via bone fluids.
• Selected biokinetic parameters based on physiological and anatomical criteria.

Main Results:

• The PSM uniquely models bone fluid mineralization.
• Model parameters are based on realistic mass transfers and bone remodeling half-times.
• Evaluated model parameter values for adults.

Conclusions:

• The PSM offers a more anatomically and physiologically accurate representation of skeletal biokinetics compared to existing models.
• This model improves the assessment of cancer risk from bone-seeking contaminants.
• The PSM is particularly valuable for modeling children's greater susceptibility to skeletal contaminants.