Basis for the ICRP's updated biokinetic model for systemic astatine

Area of Science:

• Radiological Protection
• Nuclear Medicine
• Biokinetics

Background:

• The International Commission on Radiological Protection (ICRP) has released updated biokinetic models for occupational radionuclide intakes (OIR series).
• Astatine (At), a halogen, has new biokinetic modeling detailed in OIR Part 5.
• Understanding astatine biokinetics is crucial for assessing occupational radiation exposure.

Purpose of the Study:

• To provide an overview of astatine biokinetic data.
• To describe the basis for the ICRP's updated astatine biokinetic model.
• To tabulate dose coefficients for key astatine isotopes (211At and 210At).

Main Methods:

• Review of available biokinetic data for astatine.
• Description of the ICRP's updated biokinetic model for astatine.
• Calculation and tabulation of tissue dose coefficients for intravenous injection of 210At and 211At.

Main Results:

• 211At is a promising radionuclide for targeted alpha therapy due to its properties.
• 210At, an impurity in 211At production, poses a radiation hazard via its progeny (210Po).
• Dose coefficients derived from the new model show considerable differences compared to the previous ICRP model, especially for organs like the thyroid, stomach wall, salivary glands, lungs, spleen, and kidneys.

Conclusions:

• The updated ICRP biokinetic model for astatine provides revised dose coefficients for occupational exposure assessments.
• These revised coefficients are essential for accurate radiation protection of workers handling astatine isotopes.
• The findings highlight the importance of updated biokinetic models for managing risks associated with radionuclides in therapeutic and industrial settings.