Experimental validation of a rapid Monte Carlo based micro-CT simulator

Area of Science:

• Medical Imaging
• Computational Physics
• Preclinical Research

Background:

• Accurate quantitative imaging is vital for small animal micro-CT studies.
• Monte Carlo simulations offer a powerful tool for modeling imaging systems.
• X-ray scatter is a known challenge in CT imaging, potentially impacting quantitative accuracy.

Purpose of the Study:

• To develop and validate an accelerated Monte Carlo simulator for small animal micro-CT.
• To characterize the impact of X-ray scatter on quantitative accuracy in small animal CT imaging.

Main Methods:

• Developed an accelerated Monte Carlo simulation for small animal micro-CT.
• Utilized transmission measurements with aluminum slabs to determine X-ray source spectrum.
• Validated the simulator using physical water phantoms with varying diameters and embedded rods (stainless steel, Teflon).
• Investigated scatter effects using a voxelized software phantom of a rat body.

Main Results:

• The simulator demonstrated good agreement with real micro-CT data, with normalized projection errors typically below 0.05.
• Reconstructions from simulated and real data were found to be similar.
• Scatter fractions were shown to reach tens of percent in specific regions of the rat phantom.

Conclusions:

• The developed Monte Carlo simulator is a validated and effective tool for small animal micro-CT research.
• X-ray scatter significantly impacts quantitative accuracy in small animal CT imaging and must be accounted for.
• This simulator can aid in improving the precision of quantitative measurements in preclinical CT studies.