Improved Modeling of Plutonium-DTPA Decorporation

Area of Science:

• Radiological Protection
• Biokinetics
• Chelation Therapy

Background:

• Plutonium (Pu) exposure requires chelation therapy, typically with calcium diethylenetriaminepentaacetate (Ca-DTPA).
• Existing models lack the ability to simultaneously simulate plutonium biokinetics during and after Ca-DTPA treatment.
• Accurate modeling is crucial for effective decorporation and dose assessment.

Purpose of the Study:

• To develop an improved, integrated modeling system for plutonium decorporation therapy.
• To accurately describe the biokinetic behaviors of systemic plutonium, injected Ca-DTPA, and the formed Pu-DTPA chelate.
• To enhance the prediction of plutonium retention post-treatment.

Main Methods:

• Developed a system of three linked models for plutonium, Ca-DTPA, and Pu-DTPA chelate biokinetics.
• Integrated the system with established models from ICRP Publication 100 and NCRP Report 156.
• Utilized urine bioassay and treatment data from an occupationally exposed individual for model calibration.
• Applied a coordinated network for radiation dosimetry approach with a second-order, time-dependent chelation constant.

Main Results:

• Observed a significant improvement in the goodness-of-fit to urinary excretion data.
• Achieved more accurate predictions of postmortem plutonium retention in the skeleton, liver, and wound sites.
• Demonstrated the model's capability to simulate simultaneous biokinetic behaviors.

Conclusions:

• The developed modeling system provides a more accurate approach to plutonium decorporation.
• This improved system enhances the assessment of internal plutonium contamination and treatment efficacy.
• The findings support better radiation protection strategies for individuals with plutonium exposure.