A system and method for controllably releasing laser radiation in percutaneous laser treatment is disclosed. In a preferred embodiment, an optical fiber is inserted below the skin or into a vascular lumen to a predetermined point. The fiber is connected to a source of electromagnetic radiation such as a laser. Radiation is then delivered to the treatment site while the fiber is simultaneously drawn out to the entry point. The fiber is manually withdrawn at a predetermined rate and radiation is administered in a constant power or energy level. To maintain a constant proper energy density, the speed of withdrawal is measured and sent to a controlling mechanism. The controlling mechanism modifies the power emitted, pulse length or pulse rate to ensure that the vein or tissue receives a consistent dose of energy. In one preferred embodiment, an imaging device provides the controlling device with speed information based on fiber surface textural properties or based on a series of bar code like markings. In another embodiment, additional information is collected, such as vein diameter prior to treatment, position of the distal end of the fiber, and/or impact measurements such as vibration or temperature during treatment, and the controlling mechanism adjusts output power or pulse rate in response to measurements to maintain a desired power density.
