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WO1996013211A1 - Appareil et procede d'imagerie perfectionnee pour tissus - Google Patents

Appareil et procede d'imagerie perfectionnee pour tissus Download PDF

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Publication number
WO1996013211A1
WO1996013211A1 PCT/US1995/013618 US9513618W WO9613211A1 WO 1996013211 A1 WO1996013211 A1 WO 1996013211A1 US 9513618 W US9513618 W US 9513618W WO 9613211 A1 WO9613211 A1 WO 9613211A1
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WO
WIPO (PCT)
Prior art keywords
tissue
layer
compression
imaging device
plate
Prior art date
Application number
PCT/US1995/013618
Other languages
English (en)
Inventor
Richard Moore
Daniel B. Kopans
Original Assignee
The General Hospital Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US08/329,295 external-priority patent/US5553111A/en
Application filed by The General Hospital Corporation filed Critical The General Hospital Corporation
Publication of WO1996013211A1 publication Critical patent/WO1996013211A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/50—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment specially adapted for specific body parts; specially adapted for specific clinical applications
    • A61B6/502—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment specially adapted for specific body parts; specially adapted for specific clinical applications for diagnosis of breast, i.e. mammography
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/04—Positioning of patients; Tiltable beds or the like
    • A61B6/0407—Supports, e.g. tables or beds, for the body or parts of the body
    • A61B6/0414—Supports, e.g. tables or beds, for the body or parts of the body with compression means

Definitions

  • the present invention relates to a system and method for improved tissue imaging, especially for imaging of tissues under compression.
  • the present invention relates to a mammography system and method for improved imaging of breast tissue.
  • Tissue imaging has proven to be a powerful tool for detection of cancers and other abnormalities within tissues.
  • Mammography in particular, is an excellent screening technology that has the ability to detect breast cancer several years earlier than physical examination. Early detection results in improved survival and an absolute decrease in mortality from the leading cause of non-preventable cancer deaths in women.
  • the major problems encountered with mammography systems have to do with the difficulty of positioning and retaining breast tissue within the imaging space so that the tissue is thoroughly imaged and the images produced are interpretable.
  • breast tissue is composed of glandular tissue (parenchyma), fatty tissue, and supporting connective tissue.
  • parenchyma glandular tissue
  • fatty tissue fatty tissue
  • supporting connective tissue When imaged, normal parenchyma can look very much like cancer, and can often only be distinguished from cancer by comparing different perspective images of the breast.
  • Malignancies can also be indicated by clusters of microcalcifications having a particular three-dimensional spatial arrangement that can often only be distinguished from normal clusters of microcalcifications by comparison of different perspective tissue images.
  • tissue heterogeneity can mimic cancer configurations.
  • "rolled" perspective images are achieved by direct manual mampulation of the breast tissue.
  • a mammography system capable of shearing breast tissue without need for direct manual intervention is needed.
  • a mammography system capable of shearing breast tissue that has already been positioned and imaged in a standard perspective so that different perspective images of the tissue can be prepared without removing the tissue from the imaging space (and without removing compression, if compression has been applied, see below), would be particularly desirable.
  • Another problem encountered with standard mammography systems stems from incomplete capture of all relevant tissue within a tissue imaging space.
  • Standard mammography procedures involve compression of the breast against an x-ray detector.
  • the advantages of breast compression include: (i) improved retention of breast tissue for imaging; (ii) higher contrast images with better x-ray penetration and the ability to use lower energy x-rays; (iii) spreading of the internal structures of the breast so that images of the structures can be interpreted; (iv) reduced motion of the breast during imaging; (v) reduced x-ray dose required for imaging of thinner, compressed tissue; (vi) reduced scattering of radiation, resulting in higher contrast images; and (vii) proper positioning of the breast over the detector so that as much tissue as possible can be imaged at one time.
  • compression forces the breast tissue closer to the detector, thereby improving the geometric sharpness of the image, and also permits uniform exposure over the majority of the breast tissue.
  • a significant problem encountered with standard compression systems is that compression can actually push tissue out of the field of view. This problem is particularly significant in mammography systems because breast cancers often develop close to the chest wall. Geometrically, the breast wraps around the chest and must be pulled away from the chest in order that x-ray shadows of the inner structures will be projected on the detector and will be recorded. If breast tissues are not held over the recorder, they will not be imaged and cancers will be missed. It is therefore desirable to retain as much tissue as possible within the imaging space, and particularly to be sure that tissue near the chest wall is pulled into, and retained within, the imaging space Previous attempts to solve the problem of extrusion of tissue from mammography systems during compression have included attempts to pull breast tissue into the imaging space by suction.
  • the present invention solves the problems associated with positioning and retaining tissue to be imaged within an imaging space, so that tissue analyzed with the improved tissue imaging system of the invention is thoroughly imaged and the images produced are interpretable.
  • the invention provides an improved tissue imaging system in which more tissue is retained in the imaging space and/or in which different perspective images of the tissue can be obtained without direct manual mampulation of the tissue, preferably in a single compression cycle.
  • the invention provides an improved tissue imaging system in which tissue can be sheared or "translated" without direct manual mampulation, so that different perspective images of the tissue can be determined, preferably in a single compression cycle.
  • the present invention provides a traction system for use in drawing tissue into and retaining tissue within an imaging space, and/or for use in shearing tissue in order to obtain different perspective images of a tissue.
  • the improved tissue imaging system of the present invention offers several advantages over prior art systems for tissue imaging.
  • the present invention allows tissues to be imaged from a "rolled” perspective, preferably without removal of the tissue from the imaging space and without release and re-compression of the tissue. "Rolled" perspective images can therefore be compared directly to the corresponding standard (i.e. "non-rolled") perspective images to determine if lesions (e.g. malignancies) are present in the tissue.
  • the traction system of the present invention provides the advantage that it can pull more tissue into a tissue imaging space than can prior art systems. Furthermore, the present traction system can ensure that tissue within a tissue imaging space is spread more effectively. In particular, certain embodiments of the present invention allow tissue to be pulled differentially, depending on its inherent elasticity and/or thickness (i.e. thicker, more elastic tissues would be pulled farther than thinner, more resistant tissues). Such a system will potentially minimize the pain associated with tissue imaging, particularly for imaging systems utilizing tissue compression.
  • the traction system of the present invention can also provide a disposable contact surface for tissue imaging systems.
  • Contact surfaces e.g. surfaces that come into contact with a patient's skin
  • tissue imaging system often need to be cleaned thoroughly between patients, particularly since tissues can be damaged when inserted into a localized space (especially when compressed) so that contact surfaces of the imaging system can become soiled with blood or other tissue components.
  • Such cleaning requires expenditure of time and energy.
  • the present traction system can avoid this problem by providing disposable, single-use units that pass between the skin of the subject and contact surfaces of the tissue imaging device.
  • An additional advantage of the traction system of the present invention is that some embodiments of the system can easily be designed for use with existing tissue imaging devices, such as mammography systems.
  • the present invention provides an improved tissue imaging device in which tissue to be imaged that is disposed within the device can be sheared without direct manual mampulation of that tissue.
  • the improved tissue imaging device of the present invention comprises a compression plate affixed to a base, a support plate affixed to the base and a means for shearing tissue without direct manual mampulation of that tissue.
  • the compression plate and the support plate are spaced apart from one another, allowing tissue to be positioned therebetween.
  • the shearing means is operationally arranged relative to the plates so that it shears tissue positioned between the plates.
  • either or both of the compression plate and the support plate are capable of lateral translation and/or of twisting relative to one another, so that tissue positioned between the two plates is sheared, and the means for shearing tissue comprises the plate or plates capable of lateral translation and/or of twisting.
  • a layer of radiolucent material is included that is dimensioned and constructed such that it can pass between surfaces of at least one of the plates of the device and tissue positioned therebetween. The material has sufficient tensile strength that, when tension is exerted on the layer, the layer can slide against the surfaces of the device plates without tearing.
  • the act of sliding the layer against the surfaces of the plates results in shearing of tissue positioned between the plates, and the means for shearing tissue comprises the layer.
  • the present invention also provides a layer of radiolucent material dimensioned and constructed such that it can pass between tissue disposed within a tissue imaging device and a surface of the device.
  • the material has sufficient tensile strength that, when tension is exerted on the layer, it can slide against the surfaces of the device without tearing. This sliding results in movement of the tissue relative to the surface of the tissue imaging device.
  • the present invention also provides a traction system for improved tissue imaging comprising i) at least one layer of radiolucent material dimensioned and constructed such that it can pass between tissue disposed within a tissue imaging device and at least one surface of the tissue imaging device; and ii) at least one puller engaged with the at least one layer, for exerting tension on the at least one said layer.
  • the material has sufficient tensile strength that, when tension is exerted on the at least one layer, it can slide against the surfaces of the device without tearing.
  • Tension exerted by the at least one puller on the at least one layer results in sliding of the at least one layer against the at least one surface of the tissue imaging device. This sliding motion results in movement of the tissue relative to the at least one surface of the tissue imaging device.
  • the at least one layer comprises a first layer and a second layer, and the traction system is arranged and constructed such that the at least one puller is capable of exerting different tensions on the first layer and said second layer.
  • the traction system of the present invention further comprises an element connecting the first layer and the layer, and the at least one puller is engaged with the first and second layers by means of the connecting element.
  • the first and second layers can be oriented relative to each other such that tension exerted on said first layer can result in tissue movement in a direction different from a direction of tissue movement resulting from tension exerted on said second layer.
  • the first and second layers can be tilted with respect to one another such that the layers are not parallel to one another.
  • the at least one puller comprises at least one conveyor drum around which one of the at least one layers passes.
  • the present invention also provides a compression element for a tissue imaging device comprising a compression plate in operational engagement with at least one layer of radiolucent material, the at least one layer being dimensioned and constructed such that it can pass between tissue and a surface of said compression plate.
  • the material has sufficient tensile strength that the layer can slide without tearing against the surface of the compression plate when tension is exerted on the layer, the act of sliding resulting in movement of the tissue relative to the surface of the compression plate.
  • the compression element further comprises a conveyor drum around which one of the at least one layers passes, in operational engagement, to form a conveyor. It is particularly preferred that the compression element further comprise a support plate positioned apart from the compression plate such that the compression plate and the support plate defme a compression space therebetween within which tissue can be compressed.
  • an imaging detection system comprising a detector apparatus in operational engagement with at least one layer of radiolucent material, the at least one layer being dimensioned and constructed such that it can pass between tissue and a surface of the detector apparatus.
  • the material has sufficient tensile strength that, when tension is applied to the layer, it can slide without tearing against the surface of the detector apparatus, the act of sliding resulting in movement of the tissue relative to the surfaces of said detector apparatus.
  • the imaging detection system further comprises a conveyor drum around which one of the at least one layers passes, in operational engagement, to form a conveyor.
  • the detector apparatus comprises a support plate, and the surface of the detector apparatus comprises at least a portion of a surface of the support plate.
  • the present invention also provides a method of moving a tissue relative to at least one surface of a tissue imaging device comprising the steps of positioning at least one layer of radiolucent material between at least one surface of the tissue and the at least one surface of the tissue imaging device, the radiolucent material being capable of movement relative to the at least one surface of the tissue imaging device; moving the at least one layer of radiolucent material relative to the at least one surface of the tissue imaging device such that at least a portion of the tissue also moves relative to the at least one surface of the tissue imaging device, in the direction of motion of the at least one layer of radiolucent material.
  • the invention also provides a method of shearing tissue disposed between a compression plate and a support plate of a tissue imaging device comprising laterally translating and/or twisting either or both of the compression plate and the support plate relative to one another.
  • the invention also provides a mammography device comprising a compression plate and a support plate defining a compression/imaging space therebetween.
  • At least one layer of radiolucent material is dimensioned and constructed such that it can pass between surfaces of either or both of the compression plate and the support plate and surfaces of a breast inserted within the compression/imaging space.
  • the material has sufficient tensile strength that, when tension is exerted on the at least one layer, it can slide without tearing against the surfaces. This act of sliding results in movement of the breast relative to the surfaces least one puller capable of exerting tension on the at least one layer is also included.
  • the mammography device of the present invention is arranged and constructed such that tension exerted by the at least one puller on the at least one layer results in sliding of the at least one layer against the surfaces such that the tissue moves relative to the surfaces.
  • either or both of the compression plate and the support plate are capable of lateral translation and/or of twisting with respect to the other plate, the lateral translation and/or twisting resulting in shearing of tissue disposed within the compression/imaging space between the compression plate and the support plate.
  • Figure 1 depicts a standard, prior art mammography system.
  • Figure 2A depicts an end-on view of a compression element of an embodiment of the improved tissue imaging system of the invention, and illustrates the motion herein referred to as "lateral translation”.
  • Figure 2B depicts a top view of a compression element of an embodiment of the improved tissue imaging system of the invention, and illustrates the motion herein referred to as "twisting".
  • Figure 3 depicts an embodiment of the traction system of the invention.
  • Figure 4 depict a second embodiment of the traction system of the invention.
  • Like reference numbers in the Figures refer to like elements.
  • the present invention can be implemented on any tissue imaging device in which tissue is confined in a specific space (e.g. in an imaging space).
  • the present invention is particularly valuable for tissue imaging systems that utilize tissue compression, especially for mammography systems.
  • the present invention provides means for pulling tissue into an imaging space, and/or for spreading or "shearing” (i.e. displacing one portion of the tissue with respect to another portion) tissue within that space.
  • Figure 1 shows a perspective view of a standard mammography system, including a compression system 10.
  • standard mammography systems can be obtained from any of a variety of industry sources including, for example, General Electric Corporation, Bennett X-ray Technologies, and Continental X-ray, and, as would be apparent to one of ordinary skill in the art, can readily be adapted to incorporate the improvements of the present invention.
  • each of the plates 14, 16 is attached to a base 18, and the compression plate 14 is slidably mounted in a groove 20 within the base 18.
  • the exact mode of attachment of the plates 14, 16 to the base 18 is not important, except as specified below, and different arrangements are known in the art (see, for example, U.S. Patent No. 5,029,193 to Saffer; U.S. Patent No. 3,971,950 to Evans et al.; U.S. Patent No. 4,090,084 to Epstein et al.; U.S. Patent No. 4,599,738 to Pavetta et al.).
  • the support plate 16 is spaced apart from, and typically arranged substantially parallel to, the compression plate 14.
  • the support plate 16 overlies and is constructed as part of a detection system 20, comprising a grid 52 and a cassette 50.
  • the support plate 18 can alternately be placed at a distance from the detection system 22 (see, for example U.S. Patent No. 4,599,738 to Paretta et al.).
  • the compression plate 14 and the support plate 16 need not necessarily be arranged parallel to one another (see, for example, U.S. Patent No. 5,029,193 to Saffer).
  • inner surfaces 15 and 17 of the compression plate 14 and the support plate 16, respectively need not be uniformly flat (i.e. may contain, for example, lips, angled portions, cut-out portions, etc.; see, for example, U.S. Patent No. 4,962,515 to Kopans, U.S. Patent No. 3,971,950 to Evans et al.).
  • Figure 1 also shows a medial plane 24 and associated coordinate set comprising lateral (X), axial (Y), and transverse (W) axes disposed within the compression/imaging space 12 such that the distance A between the medial plane 24 and the inner surface 15 of the compression plate 14 is substantially the same as the distance B between the medial plane 24 and the inner surface 17 of the support plate 16.
  • the orientation of the medial plane 24 with respect to the rest of the mammography device and/or with respect to the patient is not fixed.
  • the axial (Y) axis is oriented substantially vertically because the compression plate 14 and support plate 16 are substantially parallel to one another and are disposed substantially horizontally.
  • the medial plane 24 is disposed substantially equidistantly between them, and defines its associated coordinate system accordingly.
  • the compression and support plates 14 and 18 of a standard mammography device such as that depicted in Figure 1 are capable of one or both of two types of motion relative to one another: "axial motion”, in which the axial distance (A+B) between the inner surface 15 of the compression plate 14 and the inner surface 17 of the support plate 16 is uniformly varied (that is, A+B is increased or decreased by the same amount for all points on the inner surfaces 15, 17 of the plates 14, 16); and “tilting”, in which the axial distance between different points on the inner surface 15 of the compression plate 14 and the inner surface 17 of the support plate 16 is varied differently (that is, A+B is increased or decreased to a different extent at different points on the inner surfaces 15, 17 of the plates 14, 16).
  • tilting of one plate 14 or 16 with respect to the other plate 14 or 16 results in loss of parallelism, so that the compression/imaging space 12 defined after tilting has a diverging or converging volume.
  • tilting is intended to refer to motion that results in formation of a compression/imaging space 12 that converges or diverges along the lateral (X) axis and/or along the transverse (W) axis.
  • X lateral
  • W transverse
  • a standard mammography device such as that depicted in Figure 1 involves inserting a breast into the compression/imaging space 12. Compression can be applied by moving the compression plate 14 and the support plate 16 (in this case along with attendant detection system 22) closer together by axial motion of either or both plates. If desired, the compression plate 14 and support plate 16 can also be tilted with respect to one another during compression. In the standard detection system depicted in Figure 1 , the support plate 16 is fixedly mounted and the compression plate 14 is moveable within a grove 20. With such an apparatus, compression is typically applied by axially moving the compression plate 14 toward the support plate 16. Once the breast (not shown) has been positioned and compressed within the compression/imaging space 12, the breast is imaged by directing a beam of x-radiation (not shown) through the breast and detecting the x-radiation by means of the detection system 22.
  • an improved tissue imaging system is provided that is capable of shearing tissue within the tissue imaging space.
  • Figure 2 presents one embodiment of the improved tissue imaging system of the present invention, in which tissue within the tissue imaging space is sheared by motion of one or both of the compression plate 14 and the support plate 16 relative to each other.
  • the compression plate 14 and/or the support plate 16 are capable of one or both of "lateral translation” (see Figure 2A), in which the axial distance (A+B) between the inner surface 15 of the compression plate 14 and the inner surface 17 of the support plate 16 is maintained but the lateral registration between the plates 14 and 16 is varied, and "twisting" (see Figure 2B), in which either or both of plates 14 and 16 rotate with respect to one another about an axis parallel to or identical with the axial axis (Y) of the medial plane (not shown). That is, areas of plates 14, 16 that were superimposed over each other prior to twisting will no longer be superimposed over each other after twisting.
  • a standard perspective radiographic image can then be taken of the compressed tissue.
  • the compressed tissue is then sheared by laterally translating either or both of the compression plate 14 and the support plate 16 with respect to one another.
  • the compressed tissue is sheared by twisting either or both of the compression plate 14 and the support plate 16 with respect to one another.
  • shearing is performed without first de ⁇ compressing the tissue.
  • a second radiographic image is then taken, achieving a "rolled" perspective image of the tissue.
  • the two radiographic images can be compared, and triangulations can be performed, using standard imaging processing methods, so that lesions can be distinguished from normal tissue.
  • Another embodiment of the present invention utilizes a traction system to position and/or shear tissue within a tissue imaging space.
  • the traction system of the present invention comprises a radiolucent material that itself moves within the imaging space and pulls tissue along with it. The material should be sufficiently stiff that it doesn't wrinkle, but sufficiently flexible that it can bend, for example, around corners or wheels, as necessary.
  • the material should also be uniformly radiolucent to the extent that it does not interfere with the passage of imaging radiation through the tissue sample to the detector.
  • materials such as x-ray film (such as, for example, Kodak miNR film obtainable from Eastman Kodak) work well in the present traction system.
  • Other materials that are likely to be useful in the traction system of the present invention include, for example, polyester, teflon, acetate, polyvinyl chloride, and methyl polyvinyl chloride obtainable from standard industry sources.
  • the traction system of the present invention may comprise other materials in addition to the radiolucent material described above. These other materials may be, for example, engaged with, attached to, and/or molded with the radiolucent material, so long as the passage of imaging radiation through the tissue to the detector is not detrimentally disrupted.
  • FIG 3 depicts an embodiment of the traction system of the present invention in use with a standard mammography system.
  • radiolucent material 28 shown isolated in Figure 3b, is formed into a sleeve-like shape with a first layer 30 and a second layer 32, and is arranged around a breast 26.
  • the sleeve of radiolucent material 28 and breast 26 are positioned between the compression plate 14 and the support plate 16.
  • the radiolucent material 28 is arranged so that it passes between the subject and surfaces of the tissue imaging device that might otherwise be contacted by the subject's skin.
  • the material 28 passes between the inner surface 15 of the compression plate 14 and an upper surface 25 of the breast 26 between the inner surface 17 of the support plate 16 and a lower surface 27 of the breast 26, and also between imaging device surfaces that are external to the compression/imaging space 12 and areas of the subject's body that would otherwise touch those surfaces.
  • the radiolucent material 28 passes between a side 34 of the compression plate 14 and an area 36 of the subject's upper rib cage (i.e. above the breast), and also between a side 38 of the detection system 22 and an area 40 of the subject's lower rib cage (i.e. below the breast).
  • the apparatus is positioned for a "craniocaudal" (CC) projection; the apparatus could alternately be positioned for a “mediolateral oblique” (MLO) projection, in which case the material 28 of the invention would pass between the inner surface 15 of the compression plate 14 and a side of the breast, etc.
  • CC craniocaudal
  • MLO mediumolateral oblique
  • the traction system depicted in Figure 3 includes a pivotable puller 42 that is designed to exert tension on the material 28, and to thereby pull the material toward the puller, in this case away from the subject's body and farther into the compression/imaging space 12.
  • Any available pulling device could be used, such as, for example, a crank, an eccentric, a ratchet, a roller, a hand etc., so long as it is capable of pulling the radiolucent material 28 so that it slides along surfaces of the tissue imaging device.
  • motion of the material 28 pulls breast tissue toward the puller 42, thus pulling the tissue farther into the compression/imaging space 12 and/or spreading out the tissue within that space 12.
  • the puller 42 is engaged with a connecting element 44 that connects the first 30 and second 32 layers of radiolucent material. It is noted that the puller 42 need not be engaged with such a connecting element 44, but rather need only be arranged such that it is capable of exerting tension on the layers 30 and 32 to move the radiolucent material 28 relative to surfaces of the tissue imaging device. It is also noted that the connecting element 44 need not be formed of radiolucent material 26 so long as the passage of imaging radiation through the breast 28 to the detection system 22 is not disrupted. To use the traction system depicted in Figure 3 with a standard mammography device, one positions a breast 26 within the sleeve of radiolucent material 28 and within the compression/imaging space 12 of the mammography device.
  • Compression can be applied if desired. Then, tension is exerted by means of the puller 44, on the upper 30 and lower 32 layers of radiolucent material so that the material 28 slides along surfaces of the tissue imaging device, pulling the breast 26 away from the subject's body and in a direction along the axial axis (W) of the medial plane (not shown). The breast 26 is therefore pulled farther into and/or is spread out within the compression/imaging space 12.
  • the puller 44 is designed to pivot so that the first layer 30 and the second layer 32 of the radiolucent material 28 are not necessarily pulled the same distance, but rather are pulled to the same final tension.
  • Such an arrangement is desirable because, typically, not all areas of the breast 26 are equally flexible. In particular, especially after compression, the upper surface 25 of the breast 26 is typically more taut than is the lower surface 27. The bottom of the breast 26 can therefore be pulled farther without discomfort.
  • tissues 44 immediately under the breast 26 are often particularly delicate and susceptible to tearing. It is therefore desirable to be able to adjust the tension applied to different areas of the breast 26 to maximize spreading but minimize damage.
  • nipple 48 of the breast 26 may not always be in profile after the breast 26 has been pulled by the traction system of the present invention.
  • mammographers have historically preferred to take images in which the nipple is in profile, we have not found any significant benefit to such an arrangement and believe that the value of fully spread tissues is more significant than the primarily aesthetic advantages conferred by symmetric nipple positioning.
  • the radiolucent material 28 depicted in Figure 3 is arranged and constructed so that it passes between the subject and surfaces of the tissue imaging device that might otherwise be contacted by the subject's skin. While it is not necessary that the material 28 pass between all potentially touching surfaces, avoiding contact between skin and the imaging device can provide certain advantages including, for example, (i) the subject's skin is not irritated by contact with the device (and particularly is protected from sliding against the surfaces of the device); and (ii) the material 28 provides a disposable surface intervening between the device and the subject, with attendant sanitary advantages.
  • the sleeve of radiolucent material 28 depicted in Figure 3 is preferably dimensioned to avoid contact between the subject's skin and the surfaces of the imaging device.
  • portions 35 and 39 of the material passing between the subject's body and the imaging device surfaces that are external to the compression/imaging space 12 e.g. between the area 36 of the upper rib cage and the side 34 of the compression plate, and between the area 40 of the lower rib cage and the side 38 of the detection system.
  • Portions 35 and 39 of the material 28 should therefore desirably be sized so that, after the material 28 has moved relative to surfaces of the imaging device, material 28 will still pass between the subject's body and the external imaging device surfaces (e.g. sides 34 and 38).
  • portions 35 and 39 of the radiolucent material 28 should not be so long that they interfere with the imaging process. In particular, it is desirable to avoid bending of portion 35 across the path of imaging radiation. Such bending could be avoided, for example, by shortening portion 35 and/or by providing an additional support (not shown) that prevents portion 35 from interfering with the imaging radiation.
  • the radiolucent material 28 depicted in Figure 3 is preferably dimensioned to fit in a compression/imaging space 12 of a mammography device.
  • the detection system includes a film-screen cassette 50 that is part of the detection system 22.
  • the radiolucent material 10 not be significantly wider than is the film- screen cassette 50.
  • Typical film-screen cassettes such as those available from Eastman Kodak, Agfa, Dupont, or other industry sources, are 18 or 24 cm wide and 24 or 30 cm long.
  • the radiolucent material 28, then, is preferably also approximately 18 or 24 cm wide and is preferably long enough that it can fold over the breast 26 within the compression/imaging space 12, as shown, and also can pass between the subject's upper- rib-cage area 36 and the side 34 of the compression plate 14, and between the subject's lower-rib-cage area 40 and the side 38 of the detection system 22 after having been pulled.
  • the radiolucent material 28 can also be dimensioned to fit within a groove (not shown) on the support plate 16 and/or on the compression plate 14 so that edges of the material 28 are not exposed and thus will not abrade the subject whose tissue is being imaged.
  • Figure 3 depicts the radiolucent material 28 folded over the breast 26 in a sleeve-like configuration
  • alternate configurations of the material 28 can be used in the traction system of the present invention.
  • the material 28 may be configured to encompass the breast 26 on all sides in a tubular arrangement. It is not necessary that a single piece of radiolucent material 28 be used in the traction system of the present invention.
  • radiolucent material 28 could be used, each of which passes along a different portion of breast surface and each of which is engaged with either its own puller, or with the same puller.
  • the traction system of the invention may be desirable to construct the traction system of the invention so that differential tension can be applied across a single surface of the breast 26.
  • This can be accomplished in any of a variety of ways including, utilizing a variably hardened elastomer as the radiolucent material or, as mentioned above, utilizing a strip of radiolucent material 26 that only pulls one portion of a breast surface.
  • it may be useful to utilize a strip of material 26 passing down the center of the lower surface 27 of the breast 26, where tissue is often particularly thick.
  • a traction system utilizing such variable-elasticity layers will pull more flexible tissues (for example, thicker tissues) are farther than less flexible tissues, and will therefore minimize damage to the tissue and will also minimize pain. It is also not necessary that the direction of movement of the radiolucent material 28, and therefore of the breast 26, be away from the subject's body and/or substantially parallel to the transverse axis (W) of the medial plane 24. In some instances, for example, it may be desirable to spread breast tissue laterally, along the lateral axis (X) of the medial plane 24, and therefore to arrange the traction system so that the radiolucent material 10 moves laterally across the compression/imaging space 12 (i.e. into or out-of the page with respect to Figure 3).
  • FIG 4 shows an alternate embodiment of the traction system of the present invention, incorporated as part of a compression/imaging system in a mammography device.
  • a first layer 30 of radiolucent material 28 is arranged around a first drum 54 as part of a first conveyor 56.
  • the first layer 30 is engaged with the first drum 54 by means of any convenient attachment element 58.
  • the attachment element 58 comprises attachment members 60 on the radiolucent material 28 that are matingly engaged with indentations 62 in the first drum 54.
  • attachment element including, for example, a clamp, adhesive, hook-and-loop fastener (e.g. VELCROTM), or suction (i.e. vacuum).
  • the attachment members 60 depicted in Figure 4 comprise loops of radiolucent material 28.
  • the attachment members 60 may alternately comprise any material that can be inserted in the first drum indentations 62 so that the first layer 30 of radiolucent material and first drum 54 are operationally engaged with one another as a first conveyor 56.
  • the first layer 30 also wraps around the compression plate 14.
  • a second layer 32 of radiolucent material 28 passes around a second drum 64 and also around a support plate 16 that is integral with a detection system 22, as part of a second conveyor 66.
  • the second layer of radiolucent material is engaged with the second drum by means of a second attachment element 68.
  • the first 56 and second 66 conveyors depicted in Figure 4 can also be oriented relative to one another so that the first 30 and second 32 layers of radiolucent material 10 are not necessarily moved in the same direction.
  • the first conveyor 56 may be oriented with respect to the second conveyor 66 so that the upper surface 25 of the breast 26 is moved in a direction substantially perpendicular to a direction that the lower surface 27 of the breast 26 is moved.
  • Such an arrangement allows breast tissue to be pulled in different directions and particularly allows "rolled” images to be obtained with ease.
  • both "rolled" and “non-rolled” images will be obtainable during the same compression cycle, by rotating at least one of the conveyors 56 and 66 relative to the other, thereby saving time and also mmimizing stress to the subject.
  • the conveyors 56 and 66 depicted in Figure 4 also need not be arranged parallel to one another. It might be desirable to orient the components of a mammography compression device (e.g. in this case the first conveyor 56, which includes the compression plate 14, and the second conveyor 66, which includes the support plate 16) so that they are tilted toward each other and the compression/imaging space 12 has a volume that converges toward the nipple-end of the breast 26. While this arrangement has advantages in that thinner tissue can be flattened more effectively, a major disadvantage is that even more tissue is extruded from the compression/imaging space 12 under these circumstances.
  • a mammography compression device e.g. in this case the first conveyor 56, which includes the compression plate 14, and the second conveyor 66, which includes the support plate 16
  • the traction system of the present invention can overcome this disadvantage by pulling breast tissue farther into the compression/imaging space 12, so that the breast 26 can be fully imaged when the first conveyor 56 and the second conveyor 66, along with its attendant detection system 22, are tilted with respect to one another.
  • the breast 26 can be compressed by moving either or both of the first conveyor 56 and second conveyor 66 so that the distance between the two conveyors 56 and 66 is reduced.
  • either or both of the first conveyor 56 and the second conveyor 66 is activated so that the first layer 30 and/or the second layer 32 of radiolucent material moves and breast tissue is pulled in the direction of movement.
  • both conveyors 56 and 66 may first be activated so that the layers 30 and 32 of radiolucent material 28 both move in a direction away from the subject's body and substantially parallel to the long axis of the compression/imaging space 12.
  • one of the conveyors e.g.
  • the first conveyor 56 can be pivoted with respect to the other conveyor (e.g. the second conveyor 66) so that, when the first conveyor 56 is activated, the first layer 30 moves in a direction substantially pe ⁇ endicular to it's previous direction of movement and pulls breast tissue substantially laterally.
  • EXAMPLE 1 Comparison of an improved mammographic system utilizing a traction system of the invention with standard mammographic systems.
  • An improved tissue compression and imaging device that utilizes a traction system of the present invention is provided by modification of an existing device
  • Compression force in the improved device is controlled by the same method as used on the standard clinical system: the breast is compressed by a motor driven system to a preset level of compression force and additional tension is applied through a manual system before the mammogram is obtained.
  • the improved tissue compression and imaging device of the present invention has the following advantages over standard devices: 1) The new tissue compression and imaging device can improve breast compression and image quality.
  • the new device allows equal or greater volume of breast tissue to be imaged.
  • Patient radiation dose is equal or less than with standard compression systems. 4) The proposed system does not result in any increase in patient discomfort.
  • PROTOCOL Obtaining the mammograms:
  • Mammograms obtained with a conventional compression system are compared with those obtained using the improved device of the present invention on 30 randomly- selected women who are at least 40 years of age and who are not pregnant.
  • the typical procedure for screening mammograms is to obtain two mammograms for each breast.
  • a craniocaudal (CC) projection and a mediolateral oblique (MLO) projection are obtained for each breast using the conventional compression system.
  • Two additional CC and two additional MLO projections are obtained on a breast using the inventive device. Therefore, four additional views are obtained for each breast. Images are obtained both before and after traction, in order that a valid comparison of image quality can be made.
  • the mammography devices print out a label for each film obtained, which label includes the compressed breast thickness, kilovoltage, date, time, projection and the milliampere seconds (mAs).
  • the mAs, kVp, and compressed breast thickness may be used to calculate the mean glandular radiation dose.
  • the tension of the system used for each film is recorded by a technologist.
  • the patient's age and weight are also recorded.
  • the technologist also inquires as to the relative discomfort of the conventional and improved compression system, and records the answers (increase, decrease or approximately the same).
  • the comparison of films obtained with the two compression systems is based on scoring of the images by three radiologists experienced in mammography.
  • the matched pairs of images from the same breast are placed on a viewbox and each radiologist score the overall image quality, compression, and the visibility of structures in different regions of the breast.
  • Physical measures of the images will include regional film density, loss or gain in the amount of breast tissue imaged near the chest wall and breast image area (as an indicator of compression, since increased compression will result in the breast image area increasing).
  • the mean glandular radiation dose for a typical mammography image on the conventional unit that will be used is 115 mrads (average size breast).
  • the radiation dose per film with the improved device will be similar to that from a conventional compression system.
  • the risk from this radiation dose is minimal.
  • the discomfort of reimaging a breast in two views is comparable to the discomfort experienced for each breast in the standard procedure, except that the in-traction exposure is done immediately after the pre-traction exposure without releasing compression. This lengthens the compressed time by about 60 seconds.
  • the compression force used can be modified if an increase in discomfort is observed.
  • Increased breast visualization will improve the detectability of tumors residing centrally toward the chest wall and deep axillary regions. Additional views might also be avoided, through consistent complete visualization. Improved ergonomics will decrease positioning time and required skill level, thereby decreasing study time and improving comfort and data integrity (completeness).

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Abstract

L'invention concerne un système d'imagerie perfectionnée pour tissus dans lequel le tissu (26) peut être soumis à un effort de cisaillement sans manipulation manuelle directe, de sorte que différentes images en perspective du tissu (26) puissent être déterminées, de préférence dans un seul cycle de compression. Selon un aspect de l'invention, un système de traction comprenant au moins une couche de matériau transparent au rayonnement (28) est dimensionné et conçu pour que cette couche puisse être insérée entre le tissu (26) et une surface d'un dispositif d'imagerie pour tissus. Le matériau transparent au rayonnement (28) présente une résistance à la traction suffisante pour que la couche puisse glisser sans se déchirer contre la surface dudit dispositif d'imagerie, lorsqu'une tension est exercée sur la couche, le glissement induisant le déplacement du tissu (26) par rapport à la surface du dispositif d'imagerie. L'invention concerne également un procédé de déplacement du tissu (26) par rapport à au moins une surface d'un dispositif d'imagerie pour tissus.
PCT/US1995/013618 1994-10-26 1995-10-23 Appareil et procede d'imagerie perfectionnee pour tissus WO1996013211A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US08/329,295 US5553111A (en) 1994-10-26 1994-10-26 Apparatus and method for improved tissue imaging
US08/329,295 1994-10-26
US48785695A 1995-06-07 1995-06-07
US08/487,856 1995-06-07

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WO1996013211A1 true WO1996013211A1 (fr) 1996-05-09

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0955886A4 (fr) * 1996-07-12 2001-03-28 United States Surgical Corp Ensemble compressif induisant une traction pour imagerie tissulaire amelioree
WO2001066013A3 (fr) * 2000-03-06 2002-01-31 Biolucent Inc Dispositif permettant de rembourrer des surfaces de compression
FR2829918A1 (fr) * 2001-09-25 2003-03-28 Ge Med Sys Global Tech Co Llc Appareil de mammographie
EP1419735A1 (fr) * 2002-11-18 2004-05-19 Canon Kabushiki Kaisha Appareil de radiologie et méthode
US7505555B2 (en) 2004-11-02 2009-03-17 Biolucent, Llc Pads for mammography and methods for making and using them
US8401145B1 (en) 2008-10-23 2013-03-19 Beekley Corporation Imaging sheet and related method

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2142378A5 (fr) * 1971-06-12 1973-01-26 Siemens Ag

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2142378A5 (fr) * 1971-06-12 1973-01-26 Siemens Ag

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0955886A4 (fr) * 1996-07-12 2001-03-28 United States Surgical Corp Ensemble compressif induisant une traction pour imagerie tissulaire amelioree
US7616732B2 (en) 2000-03-06 2009-11-10 Biolucent, Llc Device for cushioning of compression surfaces
WO2001066013A3 (fr) * 2000-03-06 2002-01-31 Biolucent Inc Dispositif permettant de rembourrer des surfaces de compression
US9936925B2 (en) 2000-03-06 2018-04-10 Biolucent, Llc Device for cushioning of compression surfaces
US9504433B2 (en) 2000-03-06 2016-11-29 Biolucent, Llc Device for cushioning of compression surfaces
AU2001240073B2 (en) * 2000-03-06 2005-07-21 Biolucent, Llc Device for cushioning of compression surfaces in mammograph
US6968033B2 (en) 2000-03-06 2005-11-22 Biolucent, Inc. Device for cushioning of compression surfaces
US8705689B2 (en) 2000-03-06 2014-04-22 Biolucent, Llc Device for cushioning of compression surfaces
US7502441B2 (en) 2000-03-06 2009-03-10 Biolucent, Llc Device for cushioning compression surfaces
US8098793B2 (en) 2000-03-06 2012-01-17 Biolucent, Llc Device for cushioning of compression surfaces
US6845146B2 (en) 2001-09-25 2005-01-18 Ge Medical Systems Global Technology Company Llc Mammography apparatus and method
FR2829918A1 (fr) * 2001-09-25 2003-03-28 Ge Med Sys Global Tech Co Llc Appareil de mammographie
US6999552B2 (en) 2002-11-18 2006-02-14 Canon Kabushiki Kaisha Radiographic apparatus and method
EP1419735A1 (fr) * 2002-11-18 2004-05-19 Canon Kabushiki Kaisha Appareil de radiologie et méthode
US7505555B2 (en) 2004-11-02 2009-03-17 Biolucent, Llc Pads for mammography and methods for making and using them
US8401145B1 (en) 2008-10-23 2013-03-19 Beekley Corporation Imaging sheet and related method
US8718229B1 (en) 2008-10-23 2014-05-06 Beekley Corporation Imaging sheet and related method
US9498169B1 (en) 2008-10-23 2016-11-22 Beekley Corporation Imaging sheet and related method
US10617367B2 (en) 2008-10-23 2020-04-14 Beekley Corporation Imaging sheet and related method

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