Stereotactic mammography imaging system with prone position examination table and CCD camera

• US 5,289,520 A
• Filed: 10/06/1992
• Issued: 02/22/1994
• Est. Priority Date: 11/27/1991
• Status: Expired due to Term

• Current Assignee: Hologic Incorporated
• Original Assignee: Lorad Corp (Thermo Fisher Scientific Incorporated)
• Inventors: DeFreitas, Kenneth F., Storm, Jeffrey R., Pellegrino, Anthony J., Stoller, Milton, Schutz, Richard F., Camarra, David D., Scandura, Anthony M.
• Primary Examiner(s): Porta, David P.
• Assistant Examiner(s): CHU, KIM KWOK
• Application Number:
  US07/957,275
• Time in Patent Office: 504 Days
• Field of Search: 378/37, 378/181, 378/62, 378/64, 378/98, 378/208, 378/21, 378/22, 378/99, 128/653.1, 128/662.05
• US Class Current: 378/37
• CPC Class Codes: A61B 10/0233 Pointed or sharp biopsy instruments
• CPC Class Codes: A61B 6/0435 with means for imaging suspended breasts
• 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 90/10 for stereotaxic surgery, e.g. frame-based stereotaxis
• CPC Class Codes: A61B 90/11 with guides for needles or instruments, e.g. arcuate slides or ball joints
• CPC Class Codes: A61B 90/17 for soft tissue, e.g. breast-holding devices

Abstract

An elongated prone patient-supporting examining table for X-ray mammography is centrally supported at variable heights by a rear pedestal. The table is provided with a central breast-receiving aperture through which the patient'"'"'s pendulant breast is exposed to a horizontal beam of X-rays from a tubehead source mounted on an arm angularly movable through an arc of some 210° centered on the patient'"'"'s breast. The patient'"'"'s feet may be positioned at either end of the elongated table on an extensible footrest, permitting X-ray projection through more than 360° around the patient'"'"'s body. Diagnosis of suspect lesions and fine needle biopsy are both facilitated by stereotactic examination. Digital imaging using a CCD camera and image enhancement software provides magnification, contrast enhancement, window and level manipulation and high resolution images, with low exposure levels, short exposure times, and greatly reduced imaging times.

Claims

1. An X-ray table assembly for supporting a female patient in a prone position for mammography procedures, comprising:

a base having a front portion and a rear portion,

a rear pedestal upstanding from the rear protion of said base,

a substantially flat and horizontal patient-supporting platform which is supported cantilever-fashion from a rear longitudinal edge by said rear pedestal, having a free unsupported front edge, a right end, a left end, and a concavely-dished shallow torso-receiving recess extending across its central portion from said pedestal to said front edge,

means centrally positioned in said platform recess, mid-way between said right end and said left end, forming an open breast-receiving aperture for pendulant presentation of the patient'"'"'s breast therethrough below the level of the platform, wherther the patient'"'"'s head is positioned to the right or to the left of said aperture,

means forming right and left underside recesses in said platform flanking said breast-receiving aperture and said torso-receiving recess,

a C-arm pivotally mounted on the pedestal beneath the platform for angular movement about a vertical pivot axis aligned with said aperture and having a near end supporting an image receptor, and a remote end supporting an X-ray tubehead forming an X-ray source, said C-arm being dimensioned for pivotal movement through a arc of more than 180°

around the breast-receiving aperture, positioning the X-ray source in any of an infinite number of source positions ranging from the direction of one end of said platform through a lateral position remote from said rear pedestal to the direction of the other end of said platform, with the tubehead having an upper end positionable in either of said underside recesses above the level of said breast-receiving aperture, thereby facilitating X-ray source positioning around more than a 360°

range of positions, with the patient'"'"'s head positioned toward either the right end or the left end of the platform,

a fixed compression plate independent of said C-arm, positioned under said platform near said vertical pivot axis for abutting contact with the patient'"'"'s presented breast,

a movable compression paddle positioned under said platform near said first compression plate for gentle clamping of said presented breast between said compression plate and said paddle independent of said pivotally mounted C-arm, and

X-ray responsive image-forming means mounted on said image receptor.

5. The X-ray table assembly defined in claim 1, wherein the pivotal mounting of the C-arm on the rear pedestal incorporates vertical adjustment means for raising and lowering the C-arm in the direction of said vertical pivot axis between lower positions, and an uppermost position in which the tubehead'"'"'s upper end extends into either of said shallow underside recesses above the level of said breast-receiving aperture.

2. An X-ray table assembly for supporting a female patient in a prone position for mammography procedures, comprising:

a base having a front portion and a rear portion,

a rear pedestal upstanding from said rear portion of the base,

a substantially flat, horizontal, elongated patient-supporting platform which is centrally supported cantilever-fashion from a rear longitudinal edge by said rear pedestal and having a free unsupported front edge, and unsupported right and left lateral ends,

means centrally positioned in said platform between said ends, forming an open breast-receiving aperture for pendulant presentation of the patient'"'"'s breast therethrough below the level of the platform,

a C-arm having a remote end supporting an X-ray tubehead forming an X-ray source, and a near end supporting an image receptor, pivotally mounted on the rear pedestal beneath the platform for angular movement through an angular range of more than 180°

about a vertical pivot axis aligned with said aperture, positioning the X-ray source in any of an infinite number of source positions ranging from the direction of one end of said platform through a lateral position remote from said rear pedestal to the direction of the other end of said platform, thereby facilitating X-ray source positioning around more than a 360°

range of positions, with the patient'"'"'s head positioned toward either the right end or the left end of the platform,

a fixed compression plate independent of said C-arm, positioned under said platform near said vertical pivot axis for abutting contact with the patient'"'"'s presented breast,

a movable compression paddle independent of said C-arm, positioned under said platform near said first compression plate for clamping of said presented breast between said compression plate and said paddle independent of said pivotally mounted C-arm, and

X-ray responsive image-forming means mounted on said image receptor,

whereby free access is provided for attending personnel to the upper, the lateral and the lower surfaces of the patient'"'"'s pendulant breast over a range of more than 180°

, unimpeded by the rear supporting pedestal.

3. The X-ray table assembly defined in claim 2, wherein said elongated platform is provided with two extensible and retractable footrests, each movably positioned respectively at one lateral end of said platform, the elongated platform being dimensioned to support an adult prone female patient with her legs supported by one said footrest, and alternatively to support the patient lying in the opposite direction with her legs supported by the other said footrest.

4. The X-ray table assembly defined in claim 2 wherein the rear pedestal is vertically extensible and retractable, providing vertically adjustable level positioning for the platform.

6. The X-ray table assembly defined in claim 2, wherein the pivotal mounting of the C-arm on the rear pedestal provides angular pivoting movement of the C-arm about the vertical pivot axis through an arc of approximately 210°

from a first position on the rear pedestal side of the longitudinal centerline of the platform adjacent a first lateral end of the platform, forwardly beneath the front edge of the platform through a second front position remote from the pedestal to a third position on the rear pedestal side of the longitudinal centerline of the platform adjacent the second lateral end of the platform opposite to said first end, and wherein said elongated platform accommodates a patient lying prone thereon with her feet at either end, whereby X-ray examination from any X-ray tubehead source position within said approximately 210°

arc can be conducted from either side of the patient as required.

7. The X-ray table assembly defined in claim 2, wherein the pivotal mounting of the C-arm on the pedestal provides angular pivoting movement of the C-arm about the vertical pivot axis between a pair of source positions angularly offset from a central stereo axis by equal acute angles, providing X-ray images of the patient'"'"'s target breast tissue, held stationary between the clamping compression plate and paddle, produced by X-rays from each of the pair of source positions, with the X-ray beam from each source position being perpendicular to the image forming means mounted in said image receptor on said C-arm by reason of the anchored support of said image receptor opposite said X-ray tubehead on the same supporting C-arm.

8. The X-ray table assembly defined in claim 7, wherein the clamping compression plate and paddle remain fixed while the X-ray tubehead and the image receptor both permanently supported on the C-arm, move angularly together in the same angular direction about the vertical pivot axis as the tubehead moves on the C-arm between the two source positions.

9. The X-ray table assembly defined in claim 8, wherein the clamping compression plate and paddle are mounted on a compression arm mounted on the rear pedestal for pivotal movement about the same pivot axis independent of the C-arm, and wherein a needle guide is also mounted on the same compression arm, positioned for performing needle biopsies on breast tissue clamped between plate and paddle.

10. The X-ray table assembly defined in claim 2, further including X-ray responsive image-forming means mounted on said image receptor, including a charge coupled device (CCD) camera for converting visible light into an electronic signal, a phosphor plate producing a visible light image on its proximal surface in response to arriving X-radiation impinging thereon, light-directing means positioned to direct said phosphor plate'"'"'s visible light image on said proximal surface toward the CCD camera, computing means connected to the CCD camera for receipt of its electronic signal and for producing an imaging signal representative of at least a portion of the received CCD camera electronic signal, and means connected to the computer imaging signal, for displaying the imaging signal.

11. The X-ray table assembly defined in claim 10, wherein the light-directing means is a diagonally positioned pellicle mirror substantially transparent to X-rays interposed in the path of said arriving X-radiation, with its undersurface coated with a visible light-reflecting film and positioned to reflect said phosphor plate'"'"'s proximal surface visible light image toward the CCD camera, and wherein the phosphor plate, the pellicle mirror and the CCD camera are all enclosed in a compact light-tight optical system housing positioned closely adjacent to said clamping plates, whereby passage of the visible light, produced on the proximal surface of the phosphor plate, through the thickness of the phosphor plate and consequent diffusion or blurring of the visible light image are avoided.

12. The X-ray table assembly defined in claim 11 wherein said light-tight housing is provided with an X-ray transparent portion interposed in the path of said arriving X-radiation, thus allowing it to pass through said X-ray transparent pellicle mirror toward said phosphor plate.

13. The X-ray table assembly defined in claim 11, further including a second mirror positioned to reflect the visible light on the proximal surface of said phosphor plate from said pellicle mirror toward said CCD camera, whereby the optical system is folded along a bent optic axis for enhanced compactness.

14. An X-ray table assembly as defined in claim 11, wherein the computing means for producing an imaging signal representative of at least a portion of the received CCD camera electronic image includes means for generating a proportional remapping of at least a portin of the CCD camera electronic signal, and further includes means for modifying at least aportion of the imaging signal.

15. An X-ray table as defined in claim 14, wherein the modifying means includes means for varying the contrast associated with the imaging signal.

16. An X-ray table as defined in claim 15, wherein the means for varying the contrast includes means for selecting a range of luminance values of the electronic signal for which the modifying means generates a proportional remapping of at least a portion of the CCD camera electronic signal.

17. An X-ray table as defined in claim 16, wherein the modifying means includes means for sliding the range of luminance values with respect to all possible values of the CCD camera electronic signal.

18. An X-ray table as defined in claim 17, wherein the modifying means further includes means for automatically determining the range of luminance values from the CCD electronic signal for which the imaging signal proportionately remaps the CCD electronic signal.

19. An X-ray table as defined in claim 14, wherein the modifying means include means for modifying the imaging signal formed upon a neighborhood of CCD camera electronic signal values corresponding to the imaging signal.

20. An X-ray table assembly for supporting a female patient in a prone position for mammography procedures, comprising:

a base,

a pedestal upstanding from said base,

a substantially flat and horizontal patient-supporting platform which is supported cantilever-fashion from a rear longitudinal edge by said pedestal and having a free unsupported front edge,

means centrally positioned in said platform forming an open breast-receiving aperture for pendulant presentation of the patient'"'"'s breast therethrough below the level of the platform,

a C-arm pivotally mounted on the pedestal beneath the platform for angular movement about a vertical pivot axis aligned with said aperture and having a remote end supporting an X-ray tubehead forming an X-ray source, and a near end supporting an image receptor,

a fixed compression plate positioned under said platform near said vertical pivot axis for abutting contact with the patient'"'"'s presented breast,

a movable compression paddle positioned under said platform near said first compression plate for clamping of said presented breast between said compression plates independent of said pivotally mounted C-arm, and

X-ray responsive image-forming means mounted on said image receptor, including a charge coupled device (CCD) camera for converting visible light into an electronic signal, a phosphor plate producing on its proximal surface a visible light image in response to arriving X-radiation impinging thereon, light-directing means positioned to direct said phosphor plate'"'"'s proximal surface visible light image toward the CCD camera, computing means connected to the CCD camera for receipt of its electronic signal and for producing an imaging signal representative of at least a portion of the received CCD camera electronic signal, and means connected to the computer imaging signal, for displaying the imaging signal,

wherein the light-directing means is a diagonally positioned X-ray transparent pellicle mirror interposed in the path of said arriving X-radiation, with its undersurface positioned to reflect said phosphor plate'"'"'s image toward the CCD camera, and wherein the phosphor plate, the pellicle mirror and the CCD camera are all enclosed in a compact light-tight optical system housing positioned closely adjacent to said clamping plates.

21. The X-ray table assembly defined in claim 20, wherein the light-directing means is a diagonally positioned pellicle mirror interposed in the path of said arriving X-radiation, with its undersurface positioned to reflect said phosphor plate'"'"'s image toward the CCD camera, and wherein the phosphor plate, the pellicle mirror and the CCD camera are all enclosed in a compact light-tight optical system housing positioned closely adjacent to said clamping plates.

22. The X-ray table assembly defined in claim 21 wherein said light-tight housing is provided with an X-ray transparent portion interposed in the path of said arriving X-radiation, thus allowing it to pass through said X-ray transparent pellicle mirror toward said phosphor plate.

23. The X-ray table assembly defined in claim 21, further including a second mirror positoned to reflect the image of said phosphor plate from said pellicle mirror toward said CCD camera, whereby the optical system is folded along a bent optic axis for enhanced compactness.

24. An X-ray table assembly as defined in claim 21, wherein the computing means for producing an imaging signal representative of at least a portion of the received CCD camera electronic image includes means for generating a proportional remapping of at least aportion of the CCD camera electronic signal, and further includes means for modifying at least a portion of the imaging signal.

25. An X-ray table as defined in claim 24, wherein the modifying menas includes means for varying the contrast associated with the imaging signal.

26. An X-ray table as defined in claim 25, wherein the means for varying the contrast includes means for selecting a range of luminance values of the electronic signal for which the modifying means generates a proportional remapping of at least a portion of the CCD camera electronic signal.

27. An X-ray table as defined in claim 26, wherein the modifying means includes means for sliding the range of luminance values with respect to all possible values of the CCD camera electronic signal.

28. An X-ray table as defined in claim 27, wherein the modifying means further includes means for automatically determining the range of luminance values from the CCD electronic signal for which the imaging signal proportionately remaps the CCD electronic signal.

29. An X-ray table as defined in claim 24, wherein the modifying means include means for modifying the imaging signal formed upon a neighborhood of CCD camera electronic signal values corresponding to the imaging signal.

30. A compact CCD imaging assembly for converting arriving X-radiation to a digital image signal output, comprising:

a hollow camera housing positioned in the path of the arriving X-radiation and having an X-ray transparent wall member presented to receive and transmit the arriving X-radiation to the interior of the housing,

a phosphor plate positioned inside the housing in the path of the arriving X-radiation, producing on its proximal surface a visible light image corresponding to the intensity variations exhibited by the arriving X-radiation,

a thin pellicle film diagonally positioned between the transparent wall member and the phosphor plate, substantially transparent to X-radiation and having its underside bearing a light reflective coating,

and a CCD camera aligned to receive visible light produced by said phosphor plate and reflected by said reflective coating.

31. The CCD imaging assembly defined in claim 30, further including a second reflective mirror interposed between said diagonal pellicle film and said CCD camera, whereby the optic axis extending from said phosphor plate via said pellicle film to said CCD camera can be folded for compact positioning inside said housing.

32. An X-ray table assembly for supporting a female patient in a prone position for mammography procedures, comprising:

a base having a front portion and a rear portion,

a rear pedestal upstanding from said rear portion of the base,

a substantially flat, horizontal, elongated patient-supporting platform which is centrally supported cantilever-fashion from a rear longitudinal edge by said rear pedestal and having a free unsupported front edge, and unsupported right and left lateral ends,

means centrally positioned in said platform between said ends, forming an open breast-receiving aperture for pendulant presentation of the patient'"'"'s breast therethrough below the level of the platform,

a C-arm having a remote end supporting an X-ray tubehead forming an X-ray source, and a near end supporting an image receptor, pivotally mounted on the rear pedestal beneath the platform for angular movement through an angular range of more than 180°

about a vertical pivot axis aligned with said aperture, positioning the X-ray source in any of an infinite number of source positions ranging from the direction of one end of said platform through a lateral position remote from said rear pedestal to the direction of the other end of said platform, thereby facilitating X-ray source positioning around more than a 360°

range of positions, with the patient'"'"'s head positioned toward either the right end or the left end of the platform,

a fixed compression plate independent of said C-arm, positioned under said platform near said vertical pivot axis for abutting contact with the patient'"'"'s presented breast,

a movable compression paddle independent of said C-arm, positioned under said platform near said first compression plate for clamping of said presented breast between said compression plate and said paddle independent of said pivotally mounted C-arm, and

X-ray responsive image-forming means mounted on said image receptor,

with the central part of the free unsupported front edge of the patient-supporting platform being formed as a detachable segment, removable from the platform to provide a cutaway bight near said aperture accommodating the patient'"'"'s arm in a relaxed position, whereby the patient'"'"'s presented breast is freely pendulant in an undistorted position beneath the platform,

whereby free access is provided for attending personnel to the upper, the lateral and the lower surfaces of the patient'"'"'s pendulant breast over a range of more than 180°

, unimpeded by the rear supporting pedestal.