( ( ( ( Lithotripsy ( is ( ( an alternative ) ( to ( surgery ( for ( treating ( kidney stones ) ) ) ) ) ) ) ) -- ) ( ( focused ( ultrasound pulses ) ) ( are ( used ( to ( ( break ( the stones ) ) ( into ( ( smaller pieces ) ( that ( can ( be ( passed naturally ) ) ) ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NNP Lithotripsy)) (VP (VBZ is) (NP (NP (DT an) (NN alternative)) (PP (TO to) (NP (NP (NN surgery)) (PP (IN for) (S (VP (VBG treating) (NP (NN kidney) (NNS stones)))))))))) (: --) (S (NP (JJ focused) (NN ultrasound) (NNS pulses)) (VP (VBP are) (VP (VBN used) (S (VP (TO to) (VP (VB break) (NP (DT the) (NNS stones)) (PP (IN into) (NP (NP (JJR smaller) (NNS pieces)) (SBAR (WHNP (WDT that)) (S (VP (MD can) (VP (VB be) (VP (VBN passed) (ADVP (RB naturally))))))))))))))) (. .)))
Lithotripsy is an alternative to surgery for treating kidney stones--focused ultrasound pulses are used to break the stones into smaller pieces that can be passed naturally.
(ROOT (S (NP (DT The) (NN option) (S (VP (TO to) (VP (VB remove) (S (NP (NN kidney) (NNS stones)) (ADJP (JJ other) (PP (IN than) (NP (NN surgery))))))))) (VP (VBZ is) (NP (NN ultrasound) (NNS treatments))) (. .)))