Side-fire laser system with stand-off catheter, standoff catheter, and method of using surgical laser to achieve both tissue vaporization and rapid coagulation to prevent or halt bleeding

A side-firing laser system including a standoff catheter, comprising:

• an optical fiber configured to emit therapeutic laser radiation in a direction generally transverse to an axis of the fiber;
• and
• a catheter through which the optical fiber is inserted during a surgical procedure,
• wherein the catheter includes a transparent catheter tip through which the therapeutic laser radiation passes in said direction generally transverse to an axis of the fiber to vaporize tissue outside the catheter tip,
• wherein the catheter tip has an irrigation fluid exit opening to permit exit of irrigation fluid from the catheter tip,
• wherein the catheter has an opening in a side of the catheter tip, the opening having dimensions that are approximately equal to or less than cross-sectional dimensions of the therapeutic laser radiation, and
• wherein when the fiber is moved to a position at which the therapeutic laser radiation passes through the opening, said catheter being configured in a way such that when heavy water or a heavy water solution or mixture is used as the irrigation fluid, the laser radiation causes tissue coagulation rather than vaporization, and when water or saline solution or mixture is used as the irrigation fluid, the laser radiation causes tissue vaporization.