Laser lithotripsy

Thanks to the development of thin, flexible optical fibers with a high damage threshold for the radiation [1562, 1563], inner organs of the human body, such as the stomach, bladder, gallbladder or kidneys, can be selectively irradiated by laser radiation. A new technique for breaking kidney stones to pieces by irradiation with pulsed lasers (laser lithotripsy) has found increasing interest because it has several advantages compared to the ultrasonic shockwave lithotripsy [1564—1566]. 

An optical fused quartz fiber is inserted through the urinary tract until it nearly touches the stone that is to be broken. This can be monitored by X-ray diagnosis or by endoscopy through a fiber bundle that contains, besides the fiber for guiding the laser beam, other fibers for illumination, viewing and monitoring the laser-induced fluorescence (Fig. 10.62). 

First demonstrations of the capability of spectral analysis of kidney stones in vitro are illustrated in Fig. 10.63, where the fluorescence spectra of different kidney stones that had been irradiated in a water surrounding outside the body, and that were detected with the arrangement of Fig. 10.60 are shown [1567]. Further information on laser lithotripsy and spectroscopic control of this technique can be found in [1568, 1569]. 

If the pulse of a flashlamp-pumped dye laser is transported through the fiber and focused onto the kidneystone, the rapid evaporation of the stone 

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H. Schmidt-Kloiber, E. Reichel, Laser lithotripsy, inAngewamlte Lasermedizin, ed. by H.P. Berlien, G. Muller (Ecomed, Landsberg, 1989), Vt, Sect 2.12.1... 

B. C. Ihler, Laser lithotripsy system and fragmentation processes closely examined. Laser... 

R. Steiner (Ed.) Laser Lithotripsy (Springer, Berlin, Heidelberg, New York... 

Kidney stone removal using laser lithotripsy was invented in the 1980s and has revolutionised the treatment. Laser pulses delivered through a fibre optic were used to pulverise the stones and thus effectively remove them from the urinary tract. Laser lithotripsy allows kidney stone removal avoiding surgery. 

Laser catheters based on dye lasers and Nd YAG lasers have been used for laser lithotripsy, the shattering of stones inside the body. In this case, the catheter is inserted into the body and the distal tip of the power fiber is brought in contact with the stone. Dye laser. Ho YAG, or frequency-doubled Nd YAG laser pulses sent through these quartz fibers are absorbed in the stone surface and generate hot plasma. The resulting shock waves rapidly shatter the stone. This procedure is particularly useful in cases where other methods such as shock wave lithotripsy cannot be applied. Laser lithotripsy has been successfully applied on patients for the removal of urinary stones or biliary stones. (Comment an identical procedure has been used in otolaryngology for salivary gland calculi.)... 

Further information on laser lithotripsy and spectroscopic control of this technique can be found in [15.132,133]. 

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