A biokinetic and dosimetric model for ionic indium in humans

Area of Science:

• Radiopharmaceutical dosimetry
• Biokinetics and internal dosimetry
• Medical physics and radiation protection

Background:

• Ionic indium biokinetics require updated models for accurate human dosimetry.
• Existing models may not fully incorporate recent human and animal data.
• Ionic indium(III) compounds like indium chloride and arsenide are relevant in medical applications.

Purpose of the Study:

• To review biokinetic data for ionic indium in adult humans.
• To propose an updated biokinetic model for systemic indium exposure.
• To calculate absorbed and effective doses for 111In and 113mIn ions.

Main Methods:

• Development of a five-pool biokinetic model (plasma, bone marrow, liver, kidneys, soft tissues).
• Incorporation of human and new animal data for parameter refinement.
• Calculation of absorbed doses using ICRP/ICRU reference phantoms and ICRP Publication 103 guidelines.

Main Results:

• The proposed model includes subsystems for transferrin-bound indium and kidney excretion.
• Effective doses calculated for 111In and 113mIn ions are 0.25 mSv MBq-1 and 0.013 mSv MBq-1, respectively.
• The updated model provides more detailed and accurate dosimetric data compared to previous models.

Conclusions:

• The updated biokinetic and dosimetric models for ionic indium offer improved accuracy.
• This research supports more reliable internal dose assessments for indium-based radiopharmaceuticals.
• The findings contribute to enhanced radiation protection standards in nuclear medicine.