A long pulsed dye laser device for selective photothermolysis comprises at least two pulsed dye lasers, such as flash lamp excited dye lasers, each generating corresponding pulsed laser beams successively in time. These laser can be coordinated by a synchronizer that sequentially triggers the lasers. A combining network merges the pulse laser beams into a combined beam and a delivery system conveys the combined pulse laser beam to a patient. An example of a delivery device is a single optical fiber. This invention enables production of the necessary pulse widths, on the order of 2 msec, which can not be achieved by individual dye lasers, generally lower than 0.8 msec. Also disclosed is a selective photothermolysis method. This method comprises irradiating a tissue section of a patient with a pulsed laser beam having a changing color across a time period of the pulse. This pulse color is selected to maximize absorption in a target tissue of a patient in response to heating caused by a preceding portion of the pulse.
RELATED APPLICATION
This application is a Continuation of U.S. Ser. No. 08/695,661, filed Aug. 8, 1996, now U.S. Pat. No. 5,746,735 which is a File-Wrapper-Continuation of Ser. No. 08/329,195, filed Oct. 26, 1994, now abandoned, the entire teachings of which are incorporated herein by reference.
A long pulsed dye laser device for selective photothermolysis comprises at least two pulsed dye lasers, such as flash lamp excited dye lasers, each generating corresponding pulsed laser beams successively in time. These laser can be coordinated by a synchronizer that sequentially triggers the lasers. A combining network merges the pulse laser beams into a combined beam and a delivery system conveys the combined pulse laser beam to a patient. An example of a delivery device is a single optical fiber. This invention enables production of the necessary pulse widths, on the order of 2 msec, which can not be achieved by individual dye lasers, generally lower than 0.8 msec. Also disclosed is a selective photothermolysis method. This method comprises irradiating a tissue section of a patient with a pulsed laser beam having a changing color across a time period of the pulse. This pulse color is selected to maximize absorption in a target tissue of a patient in response to heating caused by a preceding portion of the pulse.
An array of light beams is swept along a main scan direction and dithered in a sub-scan direction to generate a treatment pattern of spots. The array is elongated along the sub-scan direction and the dithering has a travel that is significantly less than the length of the array in the sub-scan direction.
Tissue is treated by irradiating it with a sequence of optical pulses that are directed in sequence to various sites on the tissue. During the irradiation sequence, one or more tissue properties are measured at a site(s) that has already been irradiated. These measurements are used to adjust the parameters of subsequent optical pulses in the sequence.
