title: In vitro study of ultrasound based real-time tracking for renal stones in shock wave lithotripsy: Part II--a simulated animal experiment.
abstract: OBJECTIVE
  We have previously developed and reported an ultrasound based real-time tracking system for renal stones. In the current study we continued to verify the reliability of this tracking system by a simulated animal test.
  
  
  METHODS
  We used 13 prerecorded ultrasound stone trajectories to test the system. The real-time tracking system was implemented on the Litemed 9200 electrohydraulic lithotriptor (LiteMed Co., Taipei, Taiwan). An artificial stone and tap water were sealed in a balloon. The balloon was inserted into the pelvis of a pig kidney. While the kidney was affixed to and moved by a simulator, it was immersed in a specifically designed simulated animal model tank containing tap water. The stone was localized by ultrasound. The kidney was moved by the simulator according to a prerecorded stone trajectory. A total of 3,000 shock waves were delivered to the stone. For each recorded stone trajectory experiments were done under nontracking and tracking conditions. We performed tests of the fragment-to-weight ratio, which denotes the performance of a shock wave lithotriptor when fragmenting a stone.
  
  
  RESULTS
  The mean fragment-to-weight ratio was 55.3% +/- 25.9% in the nontracking and 100% +/- 0% in the tracking group. The difference in these 2 groups was statistically significant (paired t test p <0.01).
  
  
  CONCLUSIONS
  The ultrasound based real-time tracking system proved to improve the performance of a shock wave lithotriptor significantly when fragmenting stones in a simulated animal test. We believe that the tracking system would greatly reduce the number of shocks and time needed for treating renal stones.
authors: Department of Urology, Institute of Biomedical Engineering, National Cheng Kung University and Hospital, Tainan, Taiwan, Republic of China.
authors: C C
authors: CC
authors: Chang
authors: I
authors: I
authors: Manousakas
authors: Y R
authors: YR
authors: Pu
authors: S M
authors: SM
authors: Liang
authors: C H
authors: CH
authors: Chen
authors: T S
authors: TS
authors: Chen
authors: F M
authors: FM
authors: Yu
authors: W H
authors: WH
authors: Yang
authors: Y C
authors: YC
authors: Tong
authors: C L
authors: CL
authors: Kuo
mesh_terms: D000818:Animals; D066298:In Vitro Techniques; D007669:Kidney Calculi / Q000000981:diagnostic imaging / Q000628:therapy*; D008096:Lithotripsy; D008953:Models, Anatomic; D013552:Swine; D018084:Ultrasonography, Interventional