Endoscopic device having ultrasonic positioning

• US 7,344,493 B2
• Filed: 12/31/2001
• Issued: 03/18/2008
• Est. Priority Date: 02/26/2001
• Status: Active Grant

• Current Assignee: Medigus Limited
• Original Assignee: Medigus Limited
• Inventors: Sonnenschein, Minelu, Sonnenschein, Elazar
• Primary Examiner(s): Leubecker; John P.
• Application Number:
  US10/036,171
• Publication Number:
  US 20020151767A1
• Time in Patent Office: 2,269 Days
• Field of Search: 600/104, 600/106, 600/117, 600/118, 600/145, 600/130, 600/152
• US Class Current: 600/117
• CPC Class Codes: A61B 1/0005 combining images e.g. side-by-side, superimposed or tiled
• CPC Class Codes: A61B 1/00181 for multiple fixed viewing angles A61B1/00193 takes precedence
• CPC Class Codes: A61B 1/00193 adapted for stereoscopic vision
• CPC Class Codes: A61B 1/0051 with controlled bending of insertion part
• CPC Class Codes: A61B 1/04 combined with photographic or television appliances
• CPC Class Codes: A61B 1/2736 Gastroscopes
• CPC Class Codes: A61B 17/0686 having a forming anvil staying below the tissue during stapling
• CPC Class Codes: A61B 2017/00022 Sensing or detecting at the treatment site
• CPC Class Codes: A61B 2017/00292 mounted on or guided by flexible, e.g. catheter-like, means
• CPC Class Codes: A61B 2017/003 Steerable
• CPC Class Codes: A61B 2017/2905 flexible
• CPC Class Codes: G01S 11/08 using synchronised clocks
• CPC Class Codes: G01S 11/14 using ultrasonic, sonic, or infrasonic waves
• CPC Class Codes: G01S 11/16 using difference in transit time between electrical and acoustic signals
• CPC Class Codes: G01S 15/36 with phase comparison between the received signal and the contemporaneously transmitted signal
• CPC Class Codes: G01S 15/87 Combinations of sonar systems

Abstract

An endoscopic device includes ultrasonic emitters, receivers, and reflectors for the precise alignment of parts of an endoscope relative to each other. The methods for determining the relative position of two parts of the endoscope are based on measuring the distance between them based on the use of one or more transducers or arrays of transducers functioning as transmitters of ultrasonic signals and one or more transducers or arrays of transducers functioning as receivers of the ultrasonic signals. In preferred embodiments of the invention, at least one of the receivers is replaced by a reflector and at least one of the transmitters also functions as a receiver.

Claims

1. Endoscopic device comprising an articulation section and a system for measuring the distance between and the relative alignment of two objects located at two different locations along the length of said endoscopic device, said system comprising:

one or more single ultrasonic transducers, used to both transmit and receive the ultrasonic signals, mounted on, or near, the first object and at least one reflector mounted on, or near, the second object, said reflector being suitable to reflect back a pattern that can be translated into the position and orientation of said objects relative to each other;

wherein,

one of said objects is located on the proximal end or proximally of sald articulation section and the other of said objects is located distally of said articulation section.

2. Endoscopic device according to claim 1, wherein the reflector comprises two, or more, parallel reflecting planar surfaces intersected, at an angle of 90 degrees or less, by one or more planes to form one, or more, step-like configurations.

3. Endoscopic device according to claim 2, wherein some or all of the steps in the reflector have different depths and/or different lengths and/or different cross-sections.

4. Endoscopic device according to claim 2, wherein, for the case of reflectors having two or more steps, the total width of the steps does not exceed the beam width of the ultrasonic beam that impinges upon the reflector.

5. Endoscopic device according to claim 2, wherein the distance between reflecting surfaces (step height) is equal or greater than the echo duration multiplied by the sound velocity in the medium divided by two.

6. Endoscopic device to claim 2, wherein the reflecting surfaces of the reflectors are surrounded with ultrasonic energy absorbing material.

7. Endoscopic device according to claim 2, wherein said endoscopic device is adapted to position the two objects within a human or animal body separated by at least one layer of tissue.

8. Endoscopic device according to claim 7, wherein air gaps, which occur between the tissue and the reflecting surfaces of the reflector are filled with a hard or flexible material having an acoustical coefficient matching that of said tissue.

9. Endoscopic device according to claim 7, wherein the air gaps, which occur between the tissue and the reflecting surfaces of the reflector, are filled with medical ultrasonic gel.

10. Endoscopic device according to claim 1, wherein the reflector comprises two, or more, parallel reflecting planar surfaces separated by perpendicular surfaces to form one, or more, step-like configurations with a cylindrical symmetry created by drilling coaxial bores of different diameters.

11. Endoscopic device according to claim 1, wherein two reflectors are mounted at right angles to each other.

12. Endoscopic device according to claim 1, wherein two or more ultrasonic transducers are mounted on, or near, the first object, said transducers being mounted at a predetermined, fixed angle such that the transmitted beams intersect at a point in front of said first object and one ultrasonic reflector is mounted on, or near, the second object which is displaced according to information received from intensity measurements until said reflector is located at said intersection point, thus achieving proper positioning of said objects relative to each other.

13. Endoscopic device according to claim 1, wherein two or more reflectors are mounted on, or near, the first object and one ultrasonic transducer is mounted on, or near, the second object said transducer being composed of an array that produces a beam that can be steered by electronic means in accordance with information received from measurements of the angles to said reflectors until said angles are equal to predetermined values, thereby to achieve proper positioning of said objects relative to each other.

14. Endoscopic device according to claim 1, wherein said endoscopic device comprises an anvil unit of a stapler system, which is one of the objects to be aligned, and a stapler deployment unit containing a stapler cartridge, which is the other object.

15. An endoscopic device according to claim 14, wherein one or more reflectors of ultrasonic waves is created on or within or as an integral part of a surface of the stapler cartridge.

16. An endoscopic device according to claim 14, wherein the transducer is mounted into the stapler anvil unit or the cartridge unit.

17. Endoscopic device according to claim 1, wherein the relative alignment of the two objects is determined by use of triangulation techniques.

18. Endoscopic device according to claim 1, wherein the ultrasonic transducers are single element transducers.

19. Endoscopic device according to claim 1, wherein the ultrasonic transducers are composed of an array of elements.

20. Endoscopic device according to claim 1, wherein an aperture is placed before the transmitting ultrasonic transducers or a diverging transducer is used to cause the transmitted ultrasonic beam to diverge.

21. A method for measuring the distance between two objects located at two different locations along the length of an endoscopic device, said method comprising the steps of:

a) providing an endoscopic device according to claim 1;

b) activating the a single ultrasonic transducer used to both transmit and receive the ultrasonic signals to transmit an ultrasonic signal;

c) activating the single ultrasonic transducer used to both transmit and receive the ultrasonic signals to receive an ultrasonic signal reflected from the reflector;

d) measuring the time of flight of said signal;

e) determining the distance between said transducer and said reflector from said measured time; and

,

f) determining the distance between said two objects from the distance between said transducer and said reflector.

22. A method according to claim 21, wherein the time of flight is measured by starting a clock simultaneously with the start of transmission of an ultrasonic signal and stopping said clock when the received signal rises above a predetermined threshold.

23. A method according to claim 21, wherein the time of flight is measured by transmitting an ultrasonic signal, sampling the received signal, and carrying out a cross-correlation with a stored reference signal.

24. A method according to claim 23, comprising transmitting an ultrasonic signal consisting of a random sequence of pulses.

25. A method according to claim 24, comprising modulating the transmitted random sequence of by digital modulation.

26. A method according to claim 25, comprising carrying out the digital modulation by means of the PSK method.

27. A method according to claim 21, comprising using triangulation techniques to determine the relative distance and alignment of the two objects.

28. A method according to claim 27, comprising accomplishing the relative alignment of the two objects in three-dimensional space by:

providing a single ultrasonic transducer, used to both transmit and receive the ultrasonic signals located on, or near, the first of said objects and three reflectors located on, or near, the second object, measuring the lengths of the sides of the triangles formed by said transducer and each pair of said reflectors, and moving said transducer until a predetermined relationship between said lengths of said sides of said triangles is achieved.

29. A method according to claim 28, comprising replacing the single ultrasonic transducer, used to both transmit and receive the ultrasonic signals and the three reflectors by three ultrasonic transducers, used to both transmit and receive the ultrasonic signals and one reflector.

30. A method according to claim 27, comprising accomplishing the relative alignment of the two objects in two-dimensional space by:

providing a single ultrasonic transducer, used to both transmit and receive the ultrasonic signals located on, or near, the first of said objects and two reflectors located on, or near, the second object, measuring the length of the sides of the triangles formed by said transducer and each pair of said reflectors, and moving said transducer until a predetermined relationship between said lengths of said sides of said triangles is achieved.

31. A method according to claim 27, comprising using single element ultrasonic transducers.

32. A method according to claim 27, comprising using ultrasonic transducers comprised of an array of elements.

33. A method according to claim 27, comprising placing an aperture before the transmitting ultrasonic transducer or using a diverging transducer to cause the transmitted ultrasonic beam to diverge.

34. A method according to claim 21, comprising mounting a single ultrasonic transducer, used to both transmit and receive the ultrasonic signals on, or near, the first object and at least one reflector, which reflects back a pattern that can be translated into the position and orientation of said objects relative to each other, on, or near, the second object.

35. A method according to claim 34, wherein the reflector comprises two, or more, parallel reflecting planar surfaces intersected, at an angle of 90 degrees or less, by one or more planes to form one, or more, step-like configurations.

36. A method according to claim 35, wherein some or all of the steps in a two or more step reflector have different depths.

37. A method according to claim 35, wherein, the reflectors have two or more steps and the total width of the steps does not exceed the beam width of the ultrasonic beam that impinges upon the reflector.

38. A method according to claim 35, wherein the distance between reflecting surfaces (step height) is equal or greater than the echo duration multiplied by the sound velocity in the medium divided by two.

39. A method according to claim 35, comprising using the endoscopic device to position the two objects within a human or animal body such that they are separated by at least one layer of tissue.

40. A method according to claim 39, comprising filling the-air gaps, which occur between the tissue and the reflecting surfaces of the reflector with a hard or flexible material having an acoustical coefficient matching that of said tissue.

41. A method according to claim 39, comprising filling the air gaps, which occur between the tissue and the reflecting surfaces of the reflector with medical ultrasonic gel.

42. A method according to claim 34, wherein the reflector comprises two, or more, parallel reflecting planar surfaces separated by perpendicular surfaces to form one, or more, step-like configurations with a cylindrical symmetry created by drilling coaxial bores of different diameters.

43. A method according to claim 34, comprising mounting two reflectors at right angles to each other.

44. A method according to claim 21, comprising surrounding the reflecting surfaces of the reflectors with ultrasonic energy absorbing material.

45. A method according to claim 21, wherein the alignment of the two objects relative to each other is determined by the following steps:

using a single transducer as a transmitter/receiver of an ultrasonic beam and a reflector having at least one-step, which will give at least two distinct signals in the return beam;

correlating the signals stored in the computer main memory with those of the predefined reference signal in the computer memory;

determining the step depths from the buffers corresponding to said maxima of sald correlations, wherein, at least two local maxima of the correlation must exist and the difference(s) between them must correspond to the known depth(s) of the step(s);

if the measured depth(s) of the step(s) do not agree with the known depth(s) of sald step(s), then moving the transducer relative to the reflector and carrying out the correlation again; and

when the measured depth(s) of the step(s) do agree with the known depth(s) of sald step(s), then use the results of the correlation to determine the energy relation between said signals in said buffers.

46. A method according to claim 45, comprising using the intensity maxima from the buffer to determine the alignment.

47. A method according to claim 45, comprising using the ratio of the integration of the echoes to determine the alignment.

48. A method according to claim 21, wherein the displacement of the objects relative to each other is determined and changed by the following steps:

a) using a single transducer as a transmitter/receiver of an ultrasonic beam and a reflector having at least two-steps of different depths, which will give at least three distinct echoes in the return beam;

b) determining that the objects are not aligned if less than the expected number of echoes is returned;

c) determining the depth of the steps from the returned echoes;

d) comparing the measured depth with the known depths of the reflector, to determine the portion of the reflector upon which the ultrasonic beam impinges;

e) check that the ratio of energy of the two echoes that match the step depth are within a certain relation;

f) using the information obtained in the steps (d) and (e), to move the transmitter/receiver relative to the reflector; and

,

g) repeating steps (b) to (f) until the transmitter receiver is positioned directly in front of the reflector.

49. A method according to claim 21, wherein the distance between the transducer and the reflector is determined by using a transducer capable of transmitting ultrasonic signals at least two different wavelengths and measuring the ratio of the intensities of the received signals at each wavelength.

50. A method according to claim 21, comprising mounting two or more ultrasonic transducers, on, or near, the first of the objects, at a predetermined, fixed angle such that the transmitted beams intersect at a point in front of said first object and mounting one reflector on, or near, the second object said second object according to information received from intensity measurements until said reflector is located at said intersection point, thus achieving proper positioning of said objects relative to each other.

51. A method according to claim 50, comprising causing the intersection point of the transmitted beams to be located within the Fresnel zone of the ultrasonic transducers.

52. A method according to claim 50, comprising using focused ultrasonic transducers and mounting said ultrasound transducers such that the intersection point of the transmitted beams is located at the focal points of said transducers.

53. A method according to claim 21, comprising mounting two or more ultrasonic reflectors on, or near, the first of the objects and one ultrasonic transducer on, or near, the second object, wherein said transducer is composed of an array that produces a beam that can be steered by electronic means in accordance with information received from measurements of the angles to said receivers and said beam is steered until said angles are equal to predetermined values, thereby to achieve proper positioning of said objects relative to each other.

54. A method according to claim 21, wherein the distance between the transducer and the reflector is measured by the following steps:

generating a repetitive series of short electrical pulses or bursts of electrical pulses;

amplifying said pulses;

applying said amplified electric pulses to a transducer which converts the electrical energy to ultrasonic energy;

allowing said ultrasonic energy to propagate, in the form of a relatively narrow beam, through a medium, until it encounters a reflector which directs it back towards said transducer from which it was emitted;

receiving said ultrasonic energy by said transducer which converts it to an electrical signal;

amplifying and filtering said electrical signal;

digitizing said signal;

temporarily storing the sampled data in a separate buffer of a first-in first-out (FIFO) buffer or fast memory;

transferring the data from the FIFO or fast memory into the main computer memory;

correlating the data in each buffer with a predefined reference signal pattern stored in a computer memory;

determining the time of flight of the ultrasonic signal from the index of said buffer where the correlation with said reference signal has its maximum value; and

,

determining the distance from said time of flight.

55. A method according to claim 54, comprising generating the predefined reference signal from a properly chosen mathematical function.

56. A method according to claim 54, comprising measuring an actual received ultrasonic signal and storing it in the computer memory to serve as the predefined reference signal.