Method and apparatus to establish target coordinates for lithotripsy
First Claim
1. An apparatus for targeting a shock wave in connection with extracorporeal shock wave lithotripsy, comprising in combination:
- a. sensing means for detecting a reflection of the shock wave from a specific target and producing signals corresponding to the reflection at a plurality of predetermined locations wherein the sensing means comprises a plurality of sensors; and
b. computing means connected to said sensing means for processing said signals so as to identify a three dimensional coordinate location for said target, said computing means comprising correlation means for maximizing a correlation between signals for combinations of the sensors.
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Abstract
The invention discloses a method and apparatus for effectively localizing a stone and targeting a shock wave in connection with extracorporeal shock wave lithotripsy ("ESWL"). The technique disclosed by this invention can be adapted for use in connection with any conventional lithotripter. In this invention, an array of at least 3 and preferably 4 or more pressure transducers are used to sense the reflection from the target in response to an initial shock wave or ultrasonic wave. The sensor readings are then temporally shifted relative to one another in such a way as to maximize correlation between the signals from each sensor. The required time shifts for maximum correlation are used to calculate the differences in arrival times of reflected waves at the sensors. By knowing the original location of the sensors and establishing the time differences at which the reflected wave reaches the different sensors, a technique is disclosed to determine the vector coordinates extending between the target location and the focal point of the lithotripter.
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Citations
19 Claims
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1. An apparatus for targeting a shock wave in connection with extracorporeal shock wave lithotripsy, comprising in combination:
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a. sensing means for detecting a reflection of the shock wave from a specific target and producing signals corresponding to the reflection at a plurality of predetermined locations wherein the sensing means comprises a plurality of sensors; and b. computing means connected to said sensing means for processing said signals so as to identify a three dimensional coordinate location for said target, said computing means comprising correlation means for maximizing a correlation between signals for combinations of the sensors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An apparatus for targeting a shock wave in connection with extracorporeal shock wave lithotripsy, comprising in combination:
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a. sensing means for detecting a reflection of a shock wave from a specific target and producing signals corresponding to the reflection at a plurality of predetermined locations wherein the sensing means comprises a plurality of sensors; and b. computing means connected to said sensing means for processing said signals so as to identify a three dimensional coordinate location for said target, said computing means comprising correlation means for maximizing a correlation between signals for combinations of the senors, said computing means further comprising means for windowing the signals to obtain windowed signals, each windowed signal comprising a prominent feature of the reflection, and means for time-shifting the windowed signals.
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14. An improved lithotripter for destroying target stones by extracorporeal shock wave lithotripsy, said lithotripter including a shock wave generator for transmitting one or more shock waves to a predetermined focal point, said improvement comprising in combination:
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a. sensing means for detecting a reflection of the shock wave from a specific target and producing signals corresponding to the reflection at a plurality of predetermined locations wherein the sensing means comprises a plurality of sensors; and b. computing means connected to said sensing means for processing said signals so as to identify a three dimensional coordinate location for said target, said computing means comprising correlation means for maximizing a correlation between signals for combinations of the sensors. - View Dependent Claims (15, 16, 17, 18)
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19. A method for targeting a shock wave in extracorporeal shock wave lithotripsy, comprising in combination:
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a. generating a first shock wave and detecting a reflection of the first shock wave from a specific target with a plurality of sensors; b. producing a plurality of signals which correspond to the reflection of the shock wave at a plurality of predetermined locations; and c. processing said signals so as to identify a three dimensional coordinate location for the target, said processing comprising windowing the signal from each sensor to produce a windowed signal, correlating the signals to obtain correlated signals, and time-shifting the correlated signals to maximize a correlation between combinations of the sensors.
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Specification