Proposed biokinetic model for phosphorus

Area of Science:

• Human biokinetics
• Radiological protection
• Environmental health

Background:

• Current International Commission on Radiological Protection (ICRP) guidance on occupational intake of radionuclides relies on an established systemic phosphorus model (Publication 68, 1994).
• This model may not fully capture the dynamic distribution of phosphorus within the human body, potentially impacting dose estimations.

Purpose of the Study:

• To review existing biokinetic data for phosphorus in humans.
• To propose an updated biokinetic model for systemic phosphorus.
• To inform revised ICRP guidance on occupational radionuclide intake.

Main Methods:

• Comprehensive review of experimental, medical, and environmental data on phosphorus biokinetics.
• Development of a new time-dependent biokinetic model for systemic phosphorus.
• Comparison of dose estimates from the proposed model against the existing ICRP Publication 68 model.

Main Results:

• The proposed model offers a more realistic description of phosphorus movement and time-dependent distribution in the body.
• For acute uptake of phosphorus-32 ((32)P), dose estimates decreased by approximately 50% for bone surface and red marrow.
• For acute uptake of phosphorus-33 ((33)P), dose estimates increased by approximately 50% for bone surface and red marrow, with significant increases for liver and kidney for both isotopes.

Conclusions:

• The proposed phosphorus biokinetic model provides a more accurate representation of phosphorus distribution compared to the current ICRP model.
• Updated ICRP guidance incorporating this model could lead to more precise occupational dose assessments.
• The model's improved consistency with diverse data enhances its reliability for radiological protection standards.