High speed sector scanning apparatus having digital electronic control

• US 6,198,956 B1
• Filed: 09/30/1999
• Issued: 03/06/2001
• Est. Priority Date: 09/30/1999
• Status: Expired due to Term

• Current Assignee: Optos Plc (Nikon Corporation)
• Original Assignee: OTI Ophthalmic Technologies Inc.
• Inventors: Dunne, Shane Denis
• Primary Examiner(s): Jaworski, Francis J.
• Application Number:
  US09/409,095
• Time in Patent Office: 523 Days
• Field of Search: 600/437, 600/444-446, 600/459, 600/462-467, 736/33, 310/14-15, 310/23-24, 318/119, 318/128, 361/152-154, 359/198-199, 359/212-213
• US Class Current: 600/407
• CPC Class Codes: A61B 8/10 Eye inspection
• CPC Class Codes: A61B 8/12 in body cavities or body tracts, e.g. by using catheters catheters per se A61M25/00
• CPC Class Codes: A61B 8/4281 characterised by sound-transmitting media or devices for coupling the transducer to the tissue
• CPC Class Codes: A61B 8/445 Details of catheter construction
• CPC Class Codes: A61B 8/4461 Features of the scanning mechanism, e.g. for moving the transducer within the housing of the probe
• CPC Class Codes: G01S 15/8938 using transducers mounted for mechanical movement in two dimensions
• CPC Class Codes: G01S 15/8943 co-operating with reflectors
• CPC Class Codes: G01S 7/52079 Constructional features constructional features of transducers B06B; mounting transducers G10K11/00; constructional features of ultrasonic medical diagnostic devices A61B8/44
• CPC Class Codes: G10K 11/355 Arcuate movement

Abstract

An ultrasonic scanner has a housing, an ultrasonic transducer mounted within the housing for back-and-forth motion about a pivot, a permanent magnet affixed to the rear of the transducer, and electromagnetic means to effect movement of the transducer/magnet assembly. The electromagnetic means comprises two or more longitudinally mounted electromagnets, and optionally two radially mounted permanent magnets which serve as decelerating buffers. Electrical means are provided for energizing the transducer and receiving signals therefrom. Digitizing means are provided to convert the received signals to digital form. Sequential control means are provided to energize the electromagnet coils in a programmed sequence, and furthermore to synchronize transducer motion, periodic energization of the transducer, and digitization of signals received from the transducer. Display means are provided to present the signals received by the transducer to an operator, in the form of a time-varying tomographic image. More generally, a scanning device is provided having electromagnets co-acting with a permanent magnet mounted on a rocker, and coupled with a source and detector for high energy signals, so that a sweeping motion of the rocker can be effected, and an image of the target tissue may be reconstructed.

Claims

1. A high speed sector scanning apparatus having digital control, comprising:

a frame;

a rocker mounted on an axle near a first end of said frame, and being adapted for oscillatory movement about a rocker axis defined by said axle through a range of up to 180°

;

a first permanent magnet mounted at the end of said rocker remote from the first end of said frame so as to define a locus which is located in a plane swept by said permanent magnet during oscillatory movement of said rocker;

at least two electromagnets, each comprising coiled wire wound on an elongated magnetic core, said at least two electromagnets being mounted in said plane swept by said first permanent magnet, each of said at least two electromagnets being constructed so as to have a first end of the magnetic core thereof extending towards said locus defined by said first permanent magnet, whereby magnetic field reaction occurs between said first permanent magnet and at least one of said at least two electromagnets when electric power is selectively applied to said at least one electromagnet at any instant in time;

a flux return path mounted in said frame and magnetically connected to the ends of said at least two electromagnets;

digital electrical control means for selectively applying electric power to at least one electromagnet at any instant in time and for sequentially applying electric power to others of said at least two electromagnets over a period of time, whereby magnetic field reaction sequentially occurs between said first permanent magnet and a selected at least one electromagnet so as to cause oscillatory movement of said rocker about said rocker axis as said first permanent magnet moves in said defined locus in said swept plane;

a source of high frequency energy physically mounted so as to interact with said rocker so that energy is transmitted away from said rocker along a transmission axis of said rocker which is orthogonal to said rocker axis; and

a detector physically mounted so as to interact with said rocker and so as to detect and receive reflected frequency high energy at the same frequency as the energy from said source, when said reflected high frequency energy is reflected back to said apparatus from an object being scanned thereby.

2. The apparatus of claim 1, wherein the range of oscillatory movement of said rotor about said rotor axis is from 10°

up to 95°

.

3. The apparatus of claim 2, wherein said source of high frequency energy is an ultrasonic transducer;

wherein said apparatus further includes an acoustic window at the first end thereof, which acoustic window is acoustically transparent to high frequency energy at the operating frequency of said ultrasonic transducer; and

wherein said rocker, said transducer, said detector, and said first ends of said at least two electromagnets are sealed in a liquid-tight chamber which is defined at one end thereof by said acoustic window, and said liquid-tight chamber is filled with a liquid which is acoustically transparent to high frequency energy at least within the operating frequency range of said ultrasonic transducer.

4. An ultrasound tomographic imaging system comprising the apparatus of claim 3, together with ultrasonic image reconstruction circuitry and display means for displaying reconstructed ultrasound images.

5. The apparatus of claim 1, further including a pair of permanent rebound magnets mounted in said frame so that one of said pair of permanent rebound magnets is mounted at each end of the locus defined by said first permanent magnet mounted on said rocker, whereby a magnetic repulsion reaction occurs between said first permanent magnet mounted on said rocker and one of said permanent rebound magnets each time said first permanent magnet approaches said respective one of said permanent rebound magnets during oscillatory movement of said rocker.

6. The apparatus of claim 1, wherein each of said source of high frequency energy and said detector is mounted on said rocker, and is chosen from the group consisting of ultrasonic transducers, laser diodes, lamps, light emitting diodes, and superluminescent diodes.

7. The apparatus of claim 1, wherein each of said source of high frequency energy and said detector is physically mounted within said frame;

said apparatus further comprising a curved reflector mounted within said frame near the first ends of said at least two electromagnets, and at least one lever arm extending from said rocker axis of said rocker and having said first permanent magnet mounted on said lever arm at the end thereof remote from said rocker axis;

whereby energy transmitted from said source of high frequency energy is transmitted towards said curved reflector, and is retransmitted from said curved reflector outwardly from said apparatus past said first end of the frame thereof, towards an object to be scanned by said apparatus.

8. The apparatus of claim 7, wherein each of said source of high frequency energy and said detector is mounted on said rocker, and is chosen from the group consisting of ultrasonic transducers, laser diodes, lamps, light emitting diodes, and superluminescent diodes;

and

wherein said reflector is chosen from the group consisting of sound reflectors and mirrors.

9. The apparatus of claim 1, wherein said source of high frequency energy is a light source physically mounted within said frame, and chosen from the group consisting of laser diodes, lamps, light emitting diodes, superluminescent diodes, and light fibers connected to a light source chosen from the group consisting of laser diodes, lamps, light emitting diodes, and superluminescent diodes;

wherein a planar mirror is mounted on said rocker at an end thereof remote from said first permanent magnet;

wherein said source of high frequency energy is mounted within said frame so as to be directed at said planar mirror;

wherein said planar mirror is orthogonal to said axis of transmission; and

wherein said detector is physically mounted in said frame so as to interact with said rocker so as to detect and receive reflected high frequency energy being reflected back to said planar mirror from an object being scanned by said apparatus.

10. The apparatus of claim 1, wherein said source of high frequency energy is a source of broad coverage illumination, wherein said detector is one which detects high frequency energy from said source of broad coverage illumination as it is reflected back to said apparatus from an object being scanned thereby;

and

wherein said detector is physically mounted on said rocker.

11. The apparatus of claim 10, wherein said source of high frequency energy is a Xenon lamp.

12. The apparatus of claim 1, wherein said source of high frequency energy is a light source physically mounted within said frame, and chosen from the group consisting of laser diodes, lamps, light emitting diodes, superluminescent diodes, and light fibers connected to a light source chosen from the group consisting of laser diodes lamps, light emitting diodes, and superluminescent diodes;

wherein said source of high frequency energy is mounted on said rocker; and

wherein said detector is a stationary broad coverage detector.

13. The apparatus of claim 12, wherein said detector is a photomultipier tube.

14. The apparatus of claim 1, wherein there are n electromagnets, where n is a whole integer having a value of at least 2.

15. The apparatus of claim 14, wherein electric power is sequentially applied by said digital control means to each electromagnet one at a time, and wherein electric power is next applied by said digital control means to an electromagnet which is adjacent to the last electromagnet to have had electric power applied to it, each time the sequence of such application of electric power to said electromagnets changes.

16. The apparatus of claim 14, wherein there are at least four electromagnets, and wherein electric power is applied sequentially by said digital control means to pairs of adjacent electromagnets so that, in successive steps of the sequence of such application of electric power to said electromagnets, one of the respective pairs of electromagnets having electric power applied thereto is the same electromagnet.

17. The apparatus of claim 1, further comprising a mechanism which is mechanically coupled to said frame for selectively translating said frame under controlled conditions from one location to another.

18. The apparatus of claim 1, further comprising a mechanism which is mechanically coupled to said frame for selectively rotating said frame under controlled conditions about a longitudinal axis thereof.

19. The apparatus of claim 1, further comprising a mechanism which is mechanically coupled to said frame for selectively tilting said frame under controlled conditions about a tilt axis therefor, whereby each of said plane swept by said first permanent magnet and said transmission axis of said rocker are tilted about said tilt axis.