Method for detection of cavitations during medical application of high sonic energy
First Claim
1. In a method for predicting possible tissue damage caused by cavitation during the application of sonic high energy to the body of a patient, the sonic energy being generated extraneously by a sonic transducer and transmitted via a coupling means into the body of the patient, the sonic field traversing a spacial section internal to the body and being focused on a target zone for destruction of a target that is present within the target zone, the improvement comprising the steps of:
- generating an acoustic test signal comprising at least one pulse having at least one known characteristic;
applying the acoustic test signal to the target zone;
receiving at least one reflection of the acoustic test signal from the target zone;
converting the received at least one reflection into a reception signal;
comparing the at least one known characteristic of the test signal against a corresponding characteristic of the reception signal;
using the results of said comparison as an indication of whether or not a jump in acoustic impedance is present;
generating a control signal when the results of said comparison indicate that an impedance jump is present; and
using the presence or absence of the control signal as an indication of possible tissue injuries from cavitation caused by sonic high energy at the target zone.
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Accused Products
Abstract
A method and apparatus are described for the detection of possible tissue injuries caused by cavitation during the medical application to a patient'"'"'s body of high sonic energy which is generated extraneously by means of a sonic transducer for destruction of an element--for example a concretion--which is present in a target area. To detect the possible occurrence of cavitation the target area is acted upon by an acoustic test signal and a reception signal is generated from at least an initial reflection of the test signal. This signal is then examined by comparison with the test signal to detect the presence of an impedance jump leading to an attenuated reflection, so that a control signal may be generated upon detection of an impedance jump of this nature. Audible or visible warning signals may be engendered among others, and the sonic transducer may be deactivated if need be, by means of this control signal.
71 Citations
18 Claims
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1. In a method for predicting possible tissue damage caused by cavitation during the application of sonic high energy to the body of a patient, the sonic energy being generated extraneously by a sonic transducer and transmitted via a coupling means into the body of the patient, the sonic field traversing a spacial section internal to the body and being focused on a target zone for destruction of a target that is present within the target zone, the improvement comprising the steps of:
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generating an acoustic test signal comprising at least one pulse having at least one known characteristic; applying the acoustic test signal to the target zone; receiving at least one reflection of the acoustic test signal from the target zone; converting the received at least one reflection into a reception signal; comparing the at least one known characteristic of the test signal against a corresponding characteristic of the reception signal; using the results of said comparison as an indication of whether or not a jump in acoustic impedance is present; generating a control signal when the results of said comparison indicate that an impedance jump is present; and using the presence or absence of the control signal as an indication of possible tissue injuries from cavitation caused by sonic high energy at the target zone. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. Apparatus for applying sonic high energy to a target zone within the body of a patient, the apparatus comprising:
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a sonic transducer capable of emitting focused high energy sound; coupling means for coupling the focused high energy sound to the body of a patient; a high energy pulse generator for supplying said sonic transducer with current pulses at a preset repetition rate for the production of high energy sound; means for generating a low energy acoustic test signal of at least one pulse having at least one known characteristic; means for applying the low energy acoustic test signal to the target zone within the body of the patient; means for receiving at least one reflection of the acoustic test signal and converting the received reflection into an electric reception signal; means for comparing the at least one known characteristic of the test signal against a corresponding characteristic of the reception signal to detect impedance jumps indicating possible tissue injuries from cavitation caused by sonic high energy at the target zone; control signal generating means responsive to said comparing means for selectively generating a control signal when said comparing means detects an impedance jump; and alarm signaling means responsive to the presence of the control signal for generating a warning perceptible to a user. - View Dependent Claims (16)
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17. Apparatus for applying sonic high energy to a target zone within the body of a patient, the apparatus comprising:
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a sonic transducer capable of emitting focused high energy sound; coupling means for coupling the focused high energy sound to the body of a patient; a high energy pulse generator for supplying said sonic transducer with current pulses at a preset repetition rate for the production of high energy sound; means for generating a low energy acoustic test signal of at least one pulse having at least one known characteristic; means for applying the low energy acoustic test signal to the target zone; means for receiving at least one reflection of the acoustic test signal and converting the received reflection into an electric reception signal; means for comparing the at least one known characteristic of the test signal against a corresponding characteristic of the reception signal to detect impedance jumps indicating possible tissue injuries from cavitation caused by sonic high energy at the target zone; control signal generating means responsive to said comparing means for selectively generating a control signal when said comparing means detects an impedance jump, said high energy pulse generator being responsive to the presence of said control signal to suppress the generation of pulses for the production of high energy sound. - View Dependent Claims (18)
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Specification