Laser-assisted cryosurgery of prostate: numerical study.

Area of Science:

• Biomedical Engineering
• Oncology
• Surgical Technology

Background:

• Prostate cryosurgery aims to destroy cancerous tissue but risks damaging surrounding healthy structures like the urethra.
• Current methods lack precise control over the freezing boundary, potentially leading to collateral damage.

Purpose of the Study:

• To introduce and evaluate a new laser-assisted cryosurgery (LAC) method for enhanced urethral protection during prostate cryoablation.
• To improve the accuracy of cryoinjury confinement within the prostate.
• To explore the use of light-absorbing dyes to augment the protective thermal effect.

Main Methods:

• A finite difference heat diffusion model in polar coordinates simulated prostate freezing with laser irradiation across the urethral wall.
• Temperature-dependent thermophysical properties were incorporated into the model.
• Simulations compared conventional constant temperature heating with laser irradiation, with and without light-absorbing dyes.

Main Results:

• The proposed laser irradiation method effectively maintained urethral wall temperature above -45°C.
• Laser irradiation with light-absorbing dyes provided the thickest protected region, followed by laser irradiation alone, compared to constant temperature heating.
• The study highlighted the sensitivity of laser-assisted cryosurgery to laser power, with a need for precise control.

Conclusions:

• Laser-assisted cryosurgery offers a promising approach to protect the urethral wall and precisely confine cryoablation zones in the prostate.
• The integration of light-absorbing dyes can further enhance the protective thermal barrier.
• Accurate laser power control is critical for the safe and effective implementation of this technique.