System for quantitative radiographic imaging

• US 6,031,892 A
• Filed: 06/06/1995
• Issued: 02/29/2000
• Est. Priority Date: 12/05/1989
• Status: Expired due to Term

• Current Assignee: University Of Massachusetts
• Original Assignee: University Of Massachusetts
• Inventors: Karellas, Andrew
• Primary Examiner(s): Church, Craig E.
• Application Number:
  US08/469,895
• Time in Patent Office: 1,729 Days
• Field of Search: 378/98.3, 378/98.8, 250/370.09, 250/370.11
• US Class Current: 378/98.3
• CPC Class Codes: A61B 5/0091 for mammography
• CPC Class Codes: A61B 6/06 Diaphragms
• CPC Class Codes: A61B 6/4035 the source being combined with a filter or grating
• CPC Class Codes: A61B 6/405 Source units specially adapted to modify characteristics of the beam during the data acquisition process A61B6/4021, A61B6/4035 take precedence
• CPC Class Codes: A61B 6/4233 using matrix detectors
• CPC Class Codes: A61B 6/4241 using energy resolving detectors, e.g. photon counting
• CPC Class Codes: A61B 6/4258 for detecting non x-ray radiation, e.g. gamma radiation A61B6/037 takes precedence
• CPC Class Codes: A61B 6/4291 the detector being combined with a grid or grating
• CPC Class Codes: A61B 6/4423 related to hygiene or sterilisation
• CPC Class Codes: A61B 6/4488 Means for cooling A61B6/045 takes precedence
• CPC Class Codes: A61B 6/502 for diagnosis of breast, i.e. mammography
• CPC Class Codes: A61B 6/505 for diagnosis of bone
• CPC Class Codes: A61B 6/508 for non-human patients
• CPC Class Codes: A61B 6/512 Intraoral means
• CPC Class Codes: G21K 1/10 Scattering devices; Absorbing devices; Ionising radiation filters
• CPC Class Codes: G21K 4/00 Conversion screens for the conversion of the spatial distribution of X-rays or particle radiation into visible images, e.g. fluoroscopic screens photographic processes using X-ray intensifiers G03C5/17; discharge tubes comprising luminescent screens H01J1/62; cathode ray tubes for X-ray conversion with optical output H01J31/50
• CPC Class Codes: H04N 23/30 for generating image signals from X-rays
• CPC Class Codes: H04N 23/54 Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils
• CPC Class Codes: H04N 5/32 Transforming X-rays cameras or camera modules for generating image signals from X-rays H04N23/30; circuitry of SSIS for transforming X-rays into image signals H04N25/30

Abstract

A system for spectroscopic imaging of bodily tissue in which a scintillation screen and a charged coupled device (CCD) are used to accurately image selected tissue. An x-ray source generates x-rays which pass through a region of a subject'"'"'s body, forming an x-ray image which reaches the scintillation screen. The scintillation screen reradiates a spatial intensity pattern corresponding to the image, the pattern being detected by a CCD sensor. The image is digitized by the sensor and processed by a controller before being stored as an electronic image. Each image is directed onto an associated respective CCD or amorphous silicon detector to generate individual electronic representations of the separate images.

Claims

1. An apparatus for examining soft tissue of a patient comprising:

an x-ray radiation source emitting radiation which is directed through the soft tissue;

a scintillator receiving radiation transmitted through the soft tissue and generating an optical signal correlated with the received radiation and directing the optical signal along a first optical path;

an optical surface receiving the optical signal along the first optical path and redirecting the optical signal along a second optical path;

a binning charge couple device (CCD) that is optically coupled to the optical surface to receive the optical sign along the second optically path at a plurality of pixels and generate an electronic representation of the soft tissue; and

a CCD controller that is electrically connected to the CCD such that the CCD controller bins charge from separate pixels for readout to a data storage device.

2. The apparatus of claim 1 further comprising a display for displaying an image of the soft tissue.

3. The apparatus of claim 1 further comprising:

a display for displaying an image of the soft tissue; and

a data processor receiving the electronic representation of the soft tissue and manipulating the image of the soft tissue on the display.

4. The apparatus of claim 1 further comprising a cooler in thermal communication with the CCD to cool the CCD.

5. The apparatus of claim 1 further comprising an image intensifier coupling the optical image to the CCD.

6. The apparatus of claim 1 further comprising processing means for determining the density of the soft tissue wherein the soft tissue comprises a lesion.

7. The apparatus of claim 1 further comprising a frame holding the radiation source and the CCD in fixed relation to each other.

8. The apparatus of claim 1 wherein the CCD is uncooled.

9. The apparatus of claim 1 further comprising a processor that combines data stored by groups of adjacent pixels of the CCD to generate the electronic representation of the soft tissue.

10. The apparatus of claim 1 wherein the radiation source is located above a support surface on which the patient can be positioned and wherein the optical surface is positioned between the support surface and the scintillator.

11. The apparatus of claim 1 wherein the CCD performs time delay integration to generate the electronic representation of the soft tissue.

12. The apparatus of claim 1 wherein the CCD comprises an array of pixels larger than 512×

512 pixels.

13. The apparatus of claim 1 further comprising a lens between the optical surface and the CCD focusing the optical signal onto the CCD.

14. The apparatus of claim 1 wherein the first and second optical paths are at a right angle to each other.

15. The apparatus of claim 1 wherein the CCD further comprises a sensor that is binned during charge readout such that rectangular groups of pixels are combined.

16. The apparatus of claim 1 wherein the binnable CCD comprises 2×

2 pixel binning CCD.

17. An apparatus for examining soft tissue of patient comprising:

an x-ray radiation source emitting radiation which is directed through the soft tissue;

a scintillator receiving x-ray radiation transmitted through the tissue and generating an optical signal correlated with the received radiation and directing the optical signal along a first optical path;

a mirror transparent to the radiation transmitted through the tissue located between the scintillator and the radiation source, said mirror receiving the optical signal from the scintillator and reflecting the optical signal along a second optical path;

a binning charge coupled device (CCD) that is optically coupled to the mirror to receive the optical signal along second optical path at a plurality of pixels and generate an electronic representation of the soft tissue;

a CCD controller that is electrically connected to the CCD such the CCD controller bins charge from separate pixel readout to a data storage device; and

a lens between the scintillator and the CCD along the second optical path, the lens focusing the optical signal onto the CCD.

18. The apparatus of claim 17 further comprising a display for displaying an image of the soft tissue.

19. The apparatus of claim 17 further comprising:

a display for displaying an image of the soft tissue; and

a data processor receiving the electronic representation of the soft tissue and manipulating the image of the soft tissue on the display.

20. The apparatus of claim 17 further comprising a cooler in thermal communication with the CCD to cool the CCD.

21. The apparatus of claim 17 further comprising an image intensifier coupling the optical image to the CCD.

22. The apparatus of claim 17 further comprising processing means for determining the density of the soft tissue wherein the soft tissue comprises a lesion.

23. The apparatus of claim 17 further comprising a frame holding the radiation source and the CCD in fixed relation to each other.

24. The apparatus of claim 17 wherein the CCD is uncooled.

25. The apparatus of claim 17 further comprising a processor that combines data stored by groups of adjacent pixels of the CCD to generate the electronic representation of the soft tissue.

26. The apparatus of claim 17 further comprising CCD means for performing time delay integration to generate the electronic representation of the soft tissue.

27. The apparatus of claim 17 wherein the CCD comprises an array of pixels larger than 512×

512 pixels.

28. The apparatus of claim 17 wherein the first and second optical paths are at a right angle to each other.

29. A method of examining soft tissue in a patient comprising:

positioning the soft tissue of the patient between an x-ray radiation source and a scintillator;

directing radiation emitted by the radiation source through the soft tissue;

receiving radiation with the scintillator that is transmitted through the soft tissue and generating an optical signal correlated with the received received radiation and directing the optical signal along a first optical path;

redirecting the optical signal along second optical path

receiving the optical signal along second optical path a plurality of pixels of a binning charge coupled device (CCD);

binning charge from separate of the CCD for readout with a CCD controller that is electrically connected to the CCD;

generating a first electronic representation of the soft tissue; and

rotating the CCD relative to the soft tissue and generation a second electronic representation of the soft tissue.

30. The method of claim 29 further comprising displaying an image of the soft tissue.

31. The method of claim 29 further comprising:

displaying an image of the soft tissue; and

receiving the electronic representation of the soft tissue and manipulating the image of the soft tissue on the display.

32. The method of claim 29 further comprising cooling the CCD.

33. The method of claim 29 further comprising coupling the optical image to the CCD with an image intensifier.

34. The method of claim 29 wherein the soft tissue comprises a lesion.

35. The method of claim 29 further comprising the step of holding the radiation source and the CCD in fixed relation to each other.

36. The method of claim 29 wherein the CCD is uncooled.

37. The method of claim 29 further comprising the step of combining data stored by groups of adjacent pixels of the CCD to generate the electronic representation of the soft tissue.

38. The method of claim 29 further comprising the step of locating the radiation source above the patient whose tissue is being examined.

39. The method of claim 29 further comprising the step of performing time delay integration to generate the electronic representation of the soft tissue.

40. The method of claim 29 wherein the CCD comprises an array of pixels larger than 512×

512 pixels.

41. The method of claim 29 further comprising focusing the optical signal onto the CCD with a lens between the optical surface and the CCD.

42. The method of claim 29 wherein the first and second optical paths are at a right angle to each other.

43. The method of claim 29 further comprising performing serial and parallel binning of pixels of the CCD.

44. The method of claim 29 further comprising binning pixels during charge readout of the CCD.

45. A method of examining soft tissue of a patient comprising:

directing radiation emitted by the radiation source through the soft tissue;

directing radiation transmitted through the soft tissue through a mirror transparent to the radiation;

receiving the radiation with a scintillator that is transmitted through the mirror and generating an optical signal correlated with the received radiation and directing the optical signal back toward the mirror along a first optical path;

redirecting the optical signal along a second optical path with the mirror;

focusing the optical signal along the second optical path;

receiving the focused optical signal along the second optical path at a plurality of pixels of a charge coupled device (CCD);

binning charge from separate pixels of the CCD, the CCD being electrically connected to a CCD controller; and

performing readout of the CCD to form a binned electronic representation of the soft tissue.

46. The method of claim 45 further comprising displaying an image of the soft tissue.

47. The method of claim 45 further comprising:

displaying an image of the soft tissue; and

receiving the electronic representation of the soft tissue and manipulating the image of the soft tissue on the display.

48. The method of claim 45 further comprising cooling the CCD.

49. The method of claim 45 further comprising coupling the optical image to the CCD with an image intensifier.

50. The method of claim 45 wherein the soft tissue comprises a lesion.

51. The method of claim 45 further comprising the step of holding the radiation source and the CCD in fixed relation to each other.

52. The method of claim 45 wherein the CCD is uncooled.

53. The method of claim 45 further comprising the step of combining data stored by adjacent pixels of the CCD to generate the electronic representation of the soft tissue.

54. The method of claim 45 further comprising the step of locating the radiation source above the patient whose tissue is being examined.

55. The method of claim 45 further comprising the step of performing time delay integration to generate the electronic representation of soft tissue.

56. The method of claim 45 wherein the CCD comprises an array of pixels larger than 512×

512 pixels.

57. The method of claim 45 wherein the first and second optical paths are at a right angle to each other.

58. A method of imaging soft tissue in a patient comprising:

providing an x-ray radiation source such that radiation emitted by the source is transmitted through a patient'"'"'s soft tissue onto a scintillator;

providing an integrated silicon circuit sensor having a two dimensional array of pixel elements that detect light from the scintillator that is emitted in response to radiation from the x-ray source;

positioning a region of soft tissue the patient on a support surface;

directing x-ray radiation through through the region of the patient'"'"'s soft tissue onto the scintillator which emits a spatial intensity pattern of light that is detected by the sensor, the spatial intensity pattern being coupled to the sensor with a non-intensified optical system;

binning charge from separate pixel elements of the sensor for readout with an electronic controller; and

forming an image of the soft tissue from the binned representation.

59. The method of claim 58 wherein the step of providing a pixellated sensor comprises providing a binnable sensor.

60. The method of claim 58 further comprising providing a data processor connected to the sensor, the data processor having a memory for storing the discrete electronic representation.

61. The method of claim 58 further comprising performing pulse height analysis on the discrete electronic representation.

62. The method of claim 58 further comprising providing a fiber optic coupler between the scintillator and the sensor.

63. The method of claim 58 further comprising forming the image in less than 60 seconds after directing the x-ray radiation through the patient.

64. The method of claim 58 further comprising simultaneously irradiating the entire region of the patient with x-ray tube that is stationary relative to the patient.

65. The method of claim 58 further comprising forming an image having a resolution of at least about 1 mm.

66. The method of claim 58 further comprising providing a sensor having a two dimensional array of MOS diodes.

67. The method of claim 58 further comprising performing serial and parallel binning of pixels of the sensor.

68. The method of claim 58 further comprising binning pixels during charge readout of the sensor.