Proximity detector and radiography system

• US 20040125918A1
• Filed: 08/13/2003
• Published: 07/01/2004
• Est. Priority Date: 12/27/2002
• Status: Active Grant

• Current Assignee: GE Medical Systems Global Technology Company LLC (GE Healthcare Technologies, Inc.)
• Original Assignee: GE Medical Systems Global Technology Company LLC (GE Healthcare Technologies, Inc.)
• Inventors: Krishnaswami, Hariharan, Shanmugavel, Giridharan
• Granted Patent: US 6,985,556 B2
• Time in Patent Office: Days
• US Class Current: 378/98.8
• CPC Class Codes: A61B 6/102 Protection against mechanical damage, e.g. anti-collision devices

Abstract

Certain embodiments of the present invention provide a proximity detector having a simple configuration and an imaging system including the proximity detector. In an embodiment, a proximity detector mainly comprises: a single electrode mounted on a subject-side end of a movable member; a current feeding device for feeding a constant current to an electrostatic capacitor formed between the electrode and a ground; a discharging device for releasing charge from the electrostatic capacitor at intervals of a certain cycle; a binary-coding device for binary-coding the potential at the electrode relative to a ground based on a threshold; and a smoothing device for smoothing an output signal of the binary-coding device.

Claims

1. An imaging system, said imaging system comprising:

a movable member capable of approaching a subject; and

a proximity detector, said proximity detector indicating an approach of said movable member within a certain distance of said subject based on an electric field, said proximity detector comprising;

an electrode mounted on said movable member;

a current feeding device for feeding a current to an electrostatic capacitor formed between said electrode and a ground; and

a discharging device for releasing charge from said electrostatic capacitor at intervals of certain cycle.

2. The system of claim 1, wherein said proximity detector further comprises:

a binary-coding device for binary-coding a potential at said electrode relative to a ground based on a threshold; and

a smoothing device for smoothing an output signal of said binary-coding device.

3. The system of claim 1, wherein said electrode comprises two conductive layers electrically isolated from each other, and said current is fed to an outer layer of said conductive layers, and a voltage same as a first voltage applied to said outer layer is applied to an inner layer.

4. The system of claim 1, further comprising an x-ray irradiating device and an x-ray receiving device supported by said movable member, said x-ray irradiating device and said x-ray receiving device positioned opposed to each other with a space therebetween.

5. The system of claim 4, wherein said electrode is formed along a perimeter of a receiving surface of said x-ray receiving device.

6. The system of claim 4, wherein said electrode is formed over an outer periphery of said x-ray receiving device and a perimeter of a receiving surface thereof.

7. The system of claim 4, wherein said x-ray receiving device comprises an image intensifier.

8. The system of claim 1, wherein said movable member comprises a C-arm.

9. A proximity detector, said proximity detector comprising:

an electrode positioned on a surface;

a current feeding device for feeding a current to an electrostatic capacitor formed between said electrode and a ground;

a discharging device for releasing charge from said electrostatic capacitor at intervals of a certain cycle; and

a proximity detection device triggering an alert based on a threshold.

10. The proximity detector of claim 9, wherein said alert comprises at least one of an alarm, a log, and a motion halt command.

11. The proximity detector of claim 9, wherein said current comprises a constant current.

12. The proximity detector of claim 9, wherein said proximity detector further comprises:

a binary-coding device for binary-coding a potential at said electrode relative to a ground based on a threshold; and

a smoothing device for smoothing an output signal of said binary-coding device.

13. The proximity detector of claim 9, wherein said electrode comprises two conductive layers electrically isolated from each other, and said current is fed to an outer layer of said conductive layers, and a voltage same as a first voltage applied to said outer layer is applied to an inner layer.

14. The proximity detector of claim 9, wherein the proximity detector is used with an x-ray irradiating device and an x-ray receiving device supported by a supporting device, said x-ray irradiating device and said x-ray receiving device positioned opposed to each other with a space therebetween.

15. The proximity detector of claim 14, wherein said electrode is formed along a perimeter of a receiving surface of said x-ray receiving device.

16. The proximity detector of claim 14, wherein said electrode is formed over an outer periphery of said x-ray receiving device and a perimeter of a receiving surface thereof.

17. The proximity detector of claim 9, wherein said proximity detector uses a ramp and pedestal method to detect a change in capacitance.

18. A method for proximity detection, said method comprising:

positioning an electrode on a surface;

forming an electrostatic capacitor between said electrode and a ground;

feeding a current to said electrostatic capacitor;

releasing a charge from said electrostatic capacitor at certain intervals;

comparing a voltage across said electrode to a reference signal to form a proximity detection signal; and

triggering an alert if said proximity detection signal does not satisfy a certain threshold.

19. The method of claim 18, wherein said comparing step further comprises:

generating a binary signal based on said voltage and said reference signal; and

smoothing said binary signal to form a proximity detection signal.

20. The method of claim 18, further comprising:

positioning a patient; and

triggering an alert when said surface approaches said patient within a certain threshold distance based on said proximity detection signal.