Hyperthermia Therapy: Cancer Tissue, UDF

Hyperthermia Therapy of a Cancer Tissue, ANSYS Fluent CFD Simulation Training

Description

Common cancer treatment methods include surgery, radiotherapy, and chemotherapy, each carrying disadvantages such as aggressiveness, irreversibility, and significant side effects. Hyperthermia therapy offers an alternative approach: applying warming to prevent oxygen and nutrients from reaching unhealthy tissue, causing the proteins within that tissue to change nature in a way that surrounds cancer cells and makes them identifiable to the immune system.

This project examines blood flow through capillaries passing through tissue containing cancerous tumors, simulating hyperthermia therapy using ANSYS Fluent. The model represents a spherical region of healthy body tissue through which blood flows slowly, containing several veins arranged uniformly along the x-axis for simplification (real vein structures within body tissue more closely resemble a branching, bush-like pattern). Four spherical cancerous tumors of varying diameters are positioned at the center of this tissue, on the surface of the modeled veins. While healthy and cancerous tissue actually differ in their thermophysical properties, this simulation simplifies the problem by treating both with the same properties.

Each cancerous tumor acts as a heat source, releasing thermal energy per unit volume to drive heat transfer and substantially increase local blood flow — the central mechanism this study investigates in terms of how blood vessels and surrounding tissue respond to hyperthermia treatment.

Incoming blood flow through the capillary was set to 0.08 m/s at 310.15 K, while blood flow surrounding the capillary was set to 0.000035 m/s, also at 310.15 K. The geometry was designed in Design Modeler and meshed in ANSYS Meshing using an unstructured grid totaling 717,087 cells.

Methodology

The energy equation was activated to capture the heat transfer effects central to hyperthermia therapy. The tissue itself was modeled as a porous medium, since blood flows through the capillaries via the empty cavities within the tissue structure, with a porosity coefficient of 0.05 defined as the ratio of void space to total tissue volume.

Each of the four spherical cancer tissues was heated via simulated ultrasonic waves over a 10-second period, implemented using the Source Term option. A custom UDF defined the heat generation rate per unit volume within each sphere: approximately 10,000,000 W/m³ at each sphere's center, decreasing progressively at greater distances from that center point. The simulation was run as unsteady (transient) to capture this time-dependent heating process.

Conclusion

Results include volume rendering (3D contours) alongside standard contours of velocity, pressure, and temperature throughout the domain. The temperature distribution surrounding the cancerous tumors — the central focus and primary challenge of this simulation — is clearly captured in the resulting figures, illustrating how the applied heat source elevates local tissue temperature and drives the increased blood flow response central to the hyperthermia treatment mechanism.