Small-bubble transport and splitting dynamics in a symmetric bifurcation

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Oncology

Background:

• Gas embolotherapy uses intra-arterial bubbles to block tumor blood supply.
• Bubble behavior at vascular bifurcations is critical for treatment efficacy and safety.
• Nonhomogeneous splitting and bioeffects can occur as bubbles navigate blood vessels.

Purpose of the Study:

• To model the splitting of gas bubbles in artery and arteriole bifurcations.
• To predict splitting homogeneity and shear stress relevant to gas embolotherapy.
• To understand bubble dynamics for optimizing cancer treatment delivery.

Main Methods:

• Utilized a volume of fluid (VOF) method for bubble simulation.
• Modeled gas bubble passage through symmetric bifurcations.
• Analyzed bubble splitting and shear stress under various physical parameters.

Main Results:

• The model replicated experimentally observed bubble splitting behaviors, including reversal.
• Small bubbles (length < 2x diameter) were unlikely to split with gravitational asymmetry.
• Maximum shear stress decreased exponentially with increasing Reynolds number.

Conclusions:

• Vortex-induced shearing near bifurcations is a potential cause of endothelial cell damage.
• Understanding bubble dynamics is crucial for developing safer gas embolotherapy techniques.
• Simulation results provide insights for improving bubble delivery in cancer treatment.