A method of treating a mobile target tissue with a laser beam includes:providing a laser devicefor generating a laser beam and providing an optical fiber having a deliveryend for guiding thelaser beam to the target tissue； a controller causes the laser device togenerate one or more laserpulses substantially along the same longitudinal axis. The controller causesthe laser device toprovide one or more laser pulses. The one or more pulses are selected to allowa vapor bubbleformed by the one or more pulse to expand an amount sufficient to displace asubstantial portionof the liquid medium from the space between the delivery end of the fiber andthe target tissue.The one or more pulses are delivered to the target tissue through the vaporbubble after thevapor bubble has reached its maximum extent and has begun to collapse toreduce retropulsionof the mobile target tissue.
