Integrated X-ray source module

• US 20060098778A1
• Filed: 02/20/2003
• Published: 05/11/2006
• Est. Priority Date: 02/20/2002
• Status: Active Grant

• Current Assignee: Newton Scientific, Inc.
• Original Assignee: Inpho, Inc.
• Inventors: Shefer, Ruth E., Klinkowstein, Robert E., Feda, Francis M., Oettinger, Peter E.
• Granted Patent: US 7,448,801 B2
• Time in Patent Office: Days
• US Class Current: 378/101
• CPC Class Codes: H05G 1/06 X-ray tube and at least part of the power supply apparatus being mounted within the same housing
• CPC Class Codes: H05G 1/10 Power supply arrangements for feeding the X-ray tube supply circuits with converters in general H02M; supply circuits for emitters and amplifiers H04B1/16 - H04B1/1623

Abstract

Described is a self-contained, small, lightweight, power-efficient and radiation-shielded module that includes a miniature vacuum X-ray tube emitting X-rays of a controlled intensity and defined spectrum. Feedback control circuits are used to monitor and maintain the beam current and voltage. The X-ray tube, high-voltage power supply, and the resonant converter are encapsulated in a solid high-voltage insulating material. The module can be configured into complex geometries and can be powered by commercially available small, compact, low-voltage batteries.

Claims

1. A system that generates X-rays comprising:

an X-ray tube that emits X-rays;

electron beam current control electronics that controls an electron beam current of said X-ray tube using a first feedback signal based on a measure of an electron beam current of the X-ray tube; and

high voltage control electronics that controls a high voltage power supply using a second feedback signal based on voltage sensing, wherein a resonant converter drives said high voltage power supply via an amplitude modulated waveform drive at a substantially resonant frequency, a beam current sense resistor is connected to an anode of the X-ray tube, and said beam current sense resistor generates said first feedback signal.

2. The system of claim 1, wherein the system is included in a portable X-ray instrument.

75. The radiation-shielded X-ray module of claim 1, wherein the amplitude modulated waveform drive responds to a sensed resonant frequency.

3. A system that generates X-rays comprising:

an X-ray tube that emits X-rays;

a high voltage power supply coupled to said X-ray tube that supplies a high voltage for use with said X-ray tube and is driven by a resonant converter via an amplitude modulated waveform drive at a substantially resonant frequency, said X-ray tube including a filament; and

a control circuit that controls said high voltage power supply and is responsive to a voltage feedback signal.

4. The system of claim 3, further comprising:

means for generating said voltage feedback signal.

5. The system of claim 4, wherein said means for generating said voltage feedback signal includes a high-resistance voltage divider used to measure an actual voltage output of said high voltage power supply.

6. The system of claim 3, wherein said high voltage power supply includes:

a step-up transformer connected to said resonant converter; and

a high-voltage multiplier driven by said step-up transformer.

7. The system of claim 3, wherein the system is included in a portable X-ray instrument.

76. The radiation-shielded X-ray module of claim 3, wherein the amplitude modulated waveform drive responds to a sensed resonant frequency.

8. A radiation-shielded X-ray module comprising:

an X-ray tube that emits X-rays;

a high voltage power supply coupled to said X-ray tube that supplies a high voltage for use with said X-ray tube; and

electrical connection that connects the X-ray tube to the high voltage power supply, wherein the X-ray tube, the high voltage power supply, and the electrical connection are encapsulated in a solid, electrically-insulating material containing a radio-opaque material distributed within.

9. The radiation-shielded X-ray module of claim 8, further comprising:

a resonant converter that drives said high voltage power supply via an amplitude modulated waveform drive at a substantially resonant frequency.

10. The radiation-shielded X-ray module of claim 9, further comprising:

a step up transformer connected to said resonant converter; and

a high-voltage multiplier driven by said step up transformer.

11. The radiation-shielded X-ray module of claim 8, wherein said radio-opaque material includes at least one of:

tungsten oxide, lead oxide, calcium carbonate, a lead compound, a tungsten compound, and alumina.

12. The radiation-shielded X-ray module of claim 8, wherein an amount of said radio-opaque material is in accordance with a predetermined degree of radiation attenuation.

13. The radiation-shielded X-ray module of claim 8, further comprising:

a thin conductive layer over said solid, electrically insulating material to provide electric shielding.

14. The radiation-shielded X-ray module of claim 13, wherein said thin conductive layer is formed from one of:

a conductive metallic paint, a thin metal foil, and a metallized polymer.

15. The radiation-shielded X-ray module of claim 14, wherein said thin conductive layer is formed from a thin metal foil made from at least one of:

copper and aluminum.

16. The radiation-shielded X-ray module of claim 15, wherein said thin metal foil is adhered directly to said solid, electrically insulating material using an adhesive.

17. The radiation-shielded X-ray module of claim 8, wherein the solid, electrically-insulating material is molded into a complex shape.

18. The radiation-shielded X-ray module of claim 8, wherein the X-ray tube and the high-voltage power supply are connected by a coaxial cable.

19. The radiation-shielded X-ray module of claim 8, wherein the radiation-shielded X-ray module is included in a portable X-ray instrument.

38. The X-ray module of claim 13, wherein the encapsulating material is molded into a complex shape.

77. The radiation-shielded X-ray module of claim 9, wherein the amplitude modulated waveform drive responds to a sensed resonant frequency.

20. An X-ray module comprising

an X-ray tube,

a resonant converter,

a high voltage power supply driven by the resonant converter via an amplitude modulated waveform drive at a substantially resonant frequency,

an electrical connection that connects the X-ray tube to the high voltage power supply and connects the high voltage power supply to the resonant converter, wherein the X-ray tube, high voltage power supply, and electrical connection connecting the X-ray tube to the high voltage power supply are encapsulated in a solid, electrically-insulating material.

21. The X-ray module of claim 20, wherein said solid, electrically insulating material includes a radio-opaque material distributed within.

22. The X-ray module of claim 21, wherein said solid, electrically insulating material is formed from at least one of:

epoxy, urethane, and silicon potting compound.

23. The X-ray module of claim 21, further comprising:

a thin conductive layer over said solid, electrically insulating material to provide electric shielding.

24. The X-ray module of claim 23, wherein said thin conductive layer is formed from one of:

a conductive metallic paint, a thin metal foil, and a metallized polymer.

25. The X-ray module of claim 24, wherein said thin conductive layer is formed from a thin metal foil made from at least one of:

copper and aluminum.

26. The X-ray module of claim 25, wherein said thin metal foil is adhered directly to said solid, electrically insulating material using an adhesive.

27. The X-ray module of claim 20, wherein the solid, electrically-insulating material is molded into a complex shape.

28. The X-ray module of claim 20,wherein the X-ray tube and the high-voltage power supply are connected by a coaxial cable.

29. The X-ray module of claim 20, wherein the X-ray module is included in a portable X-ray instrument.

78. The radiation-shielded X-ray module of claim 20, wherein the amplitude modulated waveform drive responds to a sensed resonant frequency.

30. An X-ray module comprising:

an X-ray tube that includes a filament and emits X-rays;

a resonant converter;

a high-voltage power supply driven by said resonant converter via an amplitude modulated waveform drive at a substantially resonant frequency;

low-voltage control electronics; and

an electrical connection that connects the X-ray tube to the high voltage power supply, connects the low-voltage control electronics to the resonant converter, and connects the resonant converter to the high-voltage power supply.

31. The X-ray module of claim 30, wherein the X-ray tube, high-voltage power supply, and resonant converter are encapsulated in a solid, electrically insulating material.

32. The X-ray module of claim 31, wherein said solid, electrically insulating material includes a radio-opaque material distributed within.

35. The X-ray module of claim 31, wherein the solid, electrically insulating material includes an epoxy.

36. The X-ray module of claim 35, wherein said solid electrically insulating material includes a radio-opaque material distributed within, and wherein the radio-opaque material is made of a uniform distribution of particles of lead oxide throughout the epoxy.

37. The X-ray module of claim 35, wherein said solid electrically insulating material includes a radio-opaque material distributed within, and wherein the radio-opaque material is made of a uniform distribution of particles of tungsten oxide throughout the epoxy.

39. The X-ray module of claim 31, wherein a thin electrically conductive metal film is deposited on the exterior surface of the encapsulating material.

40. The X-ray module of claim 31, wherein a thin conductive metal layer conforming to the exterior surface of the encapsulating material is adhered to this surface.

41. An X-ray module of claim 30, wherein the X-ray tube and the high-voltage power supply are connected by a coaxial cable.

42. The X-ray module of claim 30, wherein the resonant converter includes means for amplitude modulation.

43. The X-ray module according to claim 30, wherein the low-voltage control electronics are located on a printed circuit board directly coupled to the high-voltage power supply.

44. The X-ray module of claim 30, wherein the low-voltage control electronics are located on a printed circuit board attached by a flexible low-voltage cable to the high-voltage power supply.

45. The X-ray module of claim 30, wherein the low-voltage control electronics are powered by one of a fixed and a variable DC source input voltage.

46. An X-ray module of claim 30, wherein a plurality of the different X-ray tubes are compatible with an architecture of the low-voltage control electronics.

47. The X-ray module of claim 30, wherein an architecture of the low-voltage control electronics employ a proportional-integral-derivative feedback control architecture.

48. The X-ray module of claim 30, wherein the low-voltage control electronics includes means to maintain a filament warming current.

49. The X-ray module of claim 30, wherein the low-voltage control electronic circuits are responsive to at least one feedback signal from at least one of:

an electron beam current of the X-ray tube, and an electron beam voltage.

50. The X-ray module of claim 30, wherein the X-ray module is included in a portable X-ray instrument.

79. The radiation-shielded X-ray module of claim 30, wherein the amplitude modulated waveform drive responds to a sensed resonant frequency.

33. (canceled)

34. (canceled)

51. A method of producing an X-ray module comprising:

encapsulating electronic components used in X-ray emission in a cast block comprising a solid, electrically insulating material including a radio-opaque material distributed within; and

surrounding said cast block by a conductive layer.

52. The method of claim 51, wherein said cast block is formed from at least one of epoxy, urethane, and a silicon potting compound.

53. The method of claim 51, further comprising:

encapsulating power and control circuit components in a cast block including a radio-opaque material distributed within.

54. The method of claim 51, further comprising:

casting said solid cast block using a two-part epoxy-resin casting system.

55. The method of claim 51, wherein said radio-opaque material includes at least one of:

tungsten oxide, lead oxide, calcium carbonate, a lead compound, a tungsten compound, lead, tungsten, alumina, and any combination of the foregoing materials.

56. The method of claim 51, wherein an amount of said radio-opaque material is in accordance with a predetermined degree of radiation attenuation.

57. The method of claim 51, wherein said conductive layer is formed from one of:

a conductive metallic paint, a thin metal foil, and a metallized polymer.

58. The method of claim 57, wherein said conductive layer is formed from a thin metal foil made from at least one of:

copper and aluminum.

59. The method of claim 58, further comprising:

adhering said thin metal foil directly to said solid, electrically insulating material using an adhesive.

60. The method of claim 51, wherein the X-ray module is included in a portable X-ray instrument.

61. Control electronics used in an X-ray emitter comprising:

electron beam current control electronics that controls an electron beam current using a first feedback signal based on current sensing of an emitted beam current, a beam current sense resistor being connected to an anode of an X-ray tube wherein said beam current sense resistor is used to generate said first feedback signal; and

high voltage control electronics that controls a high voltage power supply using a second feedback signal based on voltage sensing, wherein a resonant converter drives said high voltage power supply via an amplitude modulated waveform drive at a substantially resonant frequency.

80. The radiation-shielded X-ray module of claim 61, wherein the amplitude modulated waveform drive responds to a sensed resonant frequency.

62. A method for controlling electron beam current and voltage of an X-ray emitting device driven by a high voltage power supply comprising:

producing a first feedback signal used in electron beam current control electronics that controls an electron beam current, said first feedback signal being based on current sensing of an emitted beam current, wherein said first feedback signal is generated using a beam current sense resistor connected to an anode of an X-ray tube; and

producing a second feedback signal used in high voltage control electronics that controls a high voltage power supply, said second feedback signal being based on voltage sensing, wherein a resonant converter drives said high voltage power supply via an amplitude modulated waveform drive at a substantially resonant frequency.

81. The radiation-shielded X-ray module of claim 62, wherein the amplitude modulated waveform drive responds to a sensed resonant frequency.

63. A radiation-shielded X-ray module comprising:

an X-ray tube that emits X-rays;

a high voltage power supply coupled to said X-ray tube that supplies a high voltage for use with said X-ray tube; and

electrical connection that connects the X-ray tube to the high voltage power supply, wherein the X-ray tube is encapsulated in a solid, electrically-insulating material containing a radio-opaque material distributed within.

64. The radiation shielded X-ray module of claim 63, wherein the radiation-shielded X-ray module is included in a portable X-ray instrument.

65. The radiation-shielded X-ray module of claim 63, further comprising:

a resonant converter that drives said high voltage power supply via an amplitude modulated waveform drive at a substantially resonant frequency.

66. The radiation-shielded X-ray module of claim 65, further comprising:

a step up transformer connected to said resonant converter; and

a high-voltage multiplier driven by said step up transformer.

67. The radiation-shielded X-ray module of claim 63, wherein said radio-opaque material includes at least one of:

tungsten oxide, lead oxide, calcium carbonate, a lead compound, a tungsten compound, lead, tungsten, alumina, and any combination of the foregoing materials.

68. The radiation-shielded X-ray module of claim 63, wherein an amount of said radio-opaque material is in accordance with a predetermined degree of radiation attenuation.

69. The radiation-shielded X-ray module of claim 63, further comprising:

a thin conductive layer over said solid, electrically insulating material to provide electrical shielding.

70. The radiation-shielded X-ray module of claim 69, wherein said thin conductive layer is formed from one of:

a conductive metallic paint, a thin metal foil, and a metallized polymer.

71. The radiation-shielded X-ray module of claim 70, wherein said thin conductive layer is formed from a thin metal foil made from at least one of:

copper and aluminum.

72. The radiation-shielded X-ray module of claim 71, wherein said thin metal foil is adhered directly to said solid, electrically insulating material using an adhesive.

73. The radiation-shielded X-ray module of claim 63, wherein the solid, electrically-insulating material is molded into a complex shape.

74. The radiation-shielded X-ray module of claim 63, wherein the X-ray tube and the high-voltage power supply are connected by a coaxial cable.

82. The radiation-shielded X-ray module of claim 65, wherein the amplitude modulated waveform drive responds to a sensed resonant frequency.