B ul gar ian ▁women ▁scient ists ▁Category : 2 0 th - century ▁Bulgar ian ▁scient ists <0x0A> </s> ▁Las er ▁l ith ot ri ps y ▁is ▁a ▁surg ical ▁procedure ▁to ▁remove ▁stones ▁from ▁ur inary ▁tract , ▁i . e ., ▁kid ney , ▁u re ter , ▁bl ad der , ▁or ▁u re th ra . ▁ ▁History ▁Las er ▁l ith ot ri ps y ▁was ▁invent ed ▁at ▁the ▁Well man ▁Center ▁for ▁Ph oto ▁medicine ▁at ▁Massachusetts ▁General ▁Hospital ▁in ▁the ▁ 1 9 8 0 s ▁to ▁remove ▁impact ed ▁ur inary ▁stones . ▁Opt ical ▁fib ers ▁carry ▁light ▁p uls es ▁that ▁pul ver ize ▁the ▁stone . ▁Cand ela ▁lic ensed ▁the ▁technology ▁and ▁released ▁the ▁first ▁commercial ▁las er ▁l ith ot ri ps y ▁system . ▁ ▁Initial ly ▁ 5 0 4   nm ▁d ye ▁las ers ▁were ▁used , ▁then ▁hol m ium ▁las ers ▁were ▁studied ▁in ▁the ▁ 1 9 9 0 s . ▁ ▁Pro cedure ▁A ▁u ro log ist ▁inser ts ▁a ▁scope ▁into ▁the ▁ur inary ▁tract ▁to ▁locate ▁the ▁stone . ▁The ▁scope ▁may ▁be ▁a ▁c yst os cope , ▁u re ter os cope , ▁ren os cope ▁or ▁ne ph ros cope . ▁An ▁optical ▁fi ber ▁is ▁inserted ▁through ▁the ▁working ▁channel ▁of ▁the ▁scope , ▁and ▁las er ▁light ▁is ▁directly ▁em itted ▁to ▁the ▁stone . ▁The ▁stone ▁is ▁fragment ed ▁and