| Research Abstract |
Microwave coaxial cable; Thelenyth and diameter which are the limiting factors for resistance and capacitance of the cable were shown as 90cm and 1.80mm, respectively in a flexible slender cholangioscopic channel (FCN-15H).2. Output and shapes of microwave antennas for lithotomy; As to the output level, antennas were placed in such order as doublet, dipolar, spherical, monopolar, and tapering mono-polar shapes. Otherwise, taking such factors into consideration as resistance against insertion into a stone, injury of the cholangioscopic channel and an angulation of the apical portion of the scope, a short bipolar or monopolar antenna was preferable to other types. For a hard stone, utilization of a spherical antenna following bipolar or monopolar one was recommended. 3. Irrigation materials; feasibility of an antenna insertion into a hard stone increased in 5% glucose because of decreased current dissipation. 4. Utilization of cholelitholytic agents; Methyl tert-Butyl Ether (MTBE) softened the hard surface of a stone followed by an easy insertion of an antenna, and developed the indication of microwave lithotomy for hard cholesterol stones. Fluorocarbon was shown to be an excellent mixture solvent and a volume expander of MTBE to prevent its adverse effeots. 5. Microweve lithotony gave a hold in a hard stone (borehole) for other lithotriptors (shock wave method etc).
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