An image-based rat model for Monte Carlo organ dose calculations

Area of Science:

• Medical Physics
• Radiological Dosimetry
• Computational Biology

Background:

• Accurate absorbed dose calculations are crucial for radiation protection and medical applications.
• Existing models may lack the anatomical detail necessary for precise dosimetry in small animal research.
• Developing anatomically realistic computational models is essential for advancing radiation science.

Purpose of the Study:

• To create an anatomically realistic computational rat model for radiation dose assessment.
• To calculate conversion coefficients from kerma free-in-air to organ absorbed dose for photons.
• To evaluate the impact of anatomical variations on radiation dose distribution.

Main Methods:

• A 3D rat model was constructed from 9475 digital cryosection images.
• The Monte Carlo code MCNPX was used for dose calculations.
• Conversion coefficients were computed for photon energies from 10 keV to 10 MeV under various irradiation geometries.

Main Results:

• Detailed conversion coefficients were calculated for 13 major organs and tissues.
• The influence of organ volume, shape, location, and orientation on dose distribution was analyzed.
• The study provides supplemental data tables for practical dosimetry applications.

Conclusions:

• The developed computational rat model provides a valuable tool for accurate absorbed dose estimation.
• The model facilitates the evaluation of anatomical influences on radiation dosimetry.
• This approach can be extended for internal dose assessments in rats.