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Development of a smart holmium:YAG laser lithotriptor
C L Goldey1, D I Rosen, G B Hayes
1Physical Sciences Inc., Andover, MA 01810, USA.
Lasers in Surgery and Medicine
|January 1, 1997
Summary
This study developed a feedback control system for pulsed holmium:YAG lasers, improving tissue selectivity and safety during lithotripsy by distinguishing between hard and soft tissues.
Area of Science:
- Biomedical Engineering
- Medical Physics
- Laser Medicine
Background:
- Pulsed holmium:YAG lasers are used in medical procedures.
- Tissue selectivity and safety are critical concerns in laser lithotripsy.
- Distinguishing between calculi and surrounding soft tissue is challenging.
Purpose of the Study:
- To develop a feedback control system for pulsed holmium:YAG lasers.
- To enhance tissue selectivity and safety in laser lithotripsy.
- To discriminate between hard biological tissues (calculi) and soft tissues.
Main Methods:
- Monitoring prompt laser-induced visible/NIR photoemissions.
- Utilizing retrograde transmission over the laser delivery fiber.
- Implementing a detection algorithm with an electro-optic shutter for intrapulse feedback control.
Main Results:
- Experimental data demonstrate a feasible lithotriptor system.
- The system can deliver 1 J per pulse to calculi.
- Errant energy discharge to surrounding urinary tract tissue is limited to <= 0.1 J.
Conclusions:
- The developed feedback control system significantly improves laser safety.
- The laser's margin of safety is enhanced by an order of magnitude based on animal tissue data.
