Photoactive dye-enhanced tissue ablation for endoscopic laser prostatectomy

Area of Science:

• Biomedical Engineering
• Optical Physics
• Surgical Technology

Background:

• Laser surgery is a long-established treatment for benign prostate hyperplasia (BPH).
• High laser power (up to 200W) is currently used for rapid tissue removal.
• There is a need for methods to enhance laser-tissue interaction for lower power applications.

Purpose of the Study:

• To investigate the feasibility of using photoactive dye injection to improve laser light absorption.
• To determine if dye injection can facilitate tissue vaporization with lower laser power.
• To evaluate the efficacy of different dyes in enhancing laser ablation.

Main Methods:

• Four biocompatible photoactive dyes (amaranth, black dye, hemoglobin powder, endoscopic marker) were tested in vitro on chicken breast tissue.
• A 532 nm laser system was used with varying radiant exposure (0.9–3.9 J/cm²).
• Light absorbance, ablation threshold, and ablation performance (considering dye concentration and injection number) were measured.

Main Results:

• Injected dyes increased light absorption, lowering the ablation threshold and improving tissue removal efficiency.
• Amaranth (AR) demonstrated the highest ablation rate (44.2 ± 0.2 µm/pulse) due to superior absorbance and lower threshold.
• Preliminary canine prostate tests showed 80W with dye injection matched 120W without, indicating a 33% power reduction.

Conclusions:

• Pre-injection of photoactive dyes significantly enhances laser energy coupling and tissue removal.
• Further research is needed on dye distribution and injection parameters for predictable ablation control.
• Dye-assisted laser ablation offers a promising approach for efficient and safe low-power BPH treatment.