DE4294430C2 - Stereo=tactic mammography and needle biopsy table - Google Patents

Stereo=tactic mammography and needle biopsy table

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Publication number
DE4294430C2
DE4294430C2 DE4294430A DE4294430A DE4294430C2 DE 4294430 C2 DE4294430 C2 DE 4294430C2 DE 4294430 A DE4294430 A DE 4294430A DE 4294430 A DE4294430 A DE 4294430A DE 4294430 C2 DE4294430 C2 DE 4294430C2
Authority
DE
Germany
Prior art keywords
image
platform
characterized
patient
ray
Prior art date
Legal status (The legal status 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 status listed.)
Expired - Fee Related
Application number
DE4294430A
Other languages
German (de)
Other versions
DE4294430T1 (en
Inventor
Anthony J Pellegrino
Milton Stoller
Kenneth F Defreitas
David D Camarra
Anthony M Scandura
Richard F Schutz
Jeffrey R Storm
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Thermo Trex Corp (ndgesd Staates Delaware) San Diego
THERMO TREX CORP N D GES D STA
Original Assignee
Thermo Trex Corp (ndgesd Staates Delaware) San Diego
THERMO TREX CORP N D GES D STA
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 to US79941291A priority Critical
Priority to US07/957,275 priority patent/US5289520A/en
Application filed by Thermo Trex Corp (ndgesd Staates Delaware) San Diego, THERMO TREX CORP N D GES D STA filed Critical Thermo Trex Corp (ndgesd Staates Delaware) San Diego
Priority claimed from DE4244925A external-priority patent/DE4244925C2/en
Priority to PCT/US1992/010327 priority patent/WO1993011706A1/en
Priority to DE4244925A priority patent/DE4244925C2/en
Publication of DE4294430C2 publication Critical patent/DE4294430C2/en
Application granted granted Critical
Anticipated expiration legal-status Critical
Application status is Expired - Fee Related legal-status Critical

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Classifications

    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/50Clinical applications
    • A61B6/502Clinical applications involving diagnosis of breast, i.e. mammography
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/04Positioning of patients; Tiltable beds or the like
    • A61B6/0407Tables or beds
    • A61B6/0435Tables or beds with means for imaging suspended breasts
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B90/00Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
    • A61B90/10Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges for stereotaxic surgery, e.g. frame-based stereotaxis
    • A61B90/11Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges for stereotaxic surgery, e.g. frame-based stereotaxis with guides for needles or instruments, e.g. arcuate slides or ball joints
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B90/00Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
    • A61B90/10Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges for stereotaxic surgery, e.g. frame-based stereotaxis
    • A61B90/14Fixators for body parts, e.g. skull clamps; Constructional details of fixators, e.g. pins
    • A61B90/17Fixators for body parts, e.g. skull clamps; Constructional details of fixators, e.g. pins for soft tissue, e.g. breast-holding devices
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B10/00Other methods or instruments for diagnosis, e.g. instruments for taking a cell sample, for biopsy, for vaccination diagnosis; Sex determination; Ovulation-period determination; Throat striking implements
    • A61B10/02Instruments for taking cell samples or for biopsy
    • A61B10/0233Pointed or sharp biopsy instruments

Abstract

The biopsy table (21) includes a platform (22), on which the patient lies in a prone position with the breasts passing through an aperture (37). An image receptor (36) is mounted on a C-arm (27) and can be rotated about an axis (29) able to be positioned between the patient`s breasts or against the underside of a breast. A tube-head (28) which delivers X-rays to the patient is positioned at the patient`s head end of the platform. The image receptor and a compression plate (53) positioned on the underside of the breast has a compression paddle (38) on the upper side of the breast, and are mounted on a compression arm (50) which also supports a needle guide (39) which is used to guide a biopsy needle to a lesion.

Description

The present invention relates to a device for stereotactic mammography phieuntersuchung according to the preamble of claim 1 or 26.

Since the publication of an article entitled "Stereotactic Instrument for a Neadle Biopsy of the Mamma "by Jan Bolmgren et al, published July 1977 in the American Journal of Roentgenology, Vol. 129, page 121, has puncture biopsy of pathological breast tissue changes, the unnecessary surgical intervention in the tissue of the patient minimized, experienced increasing acceptance. The leadership of Needed puncture needle for biopsy using stereotactic radiographs Conventionally, the development of two X-ray film images and de comparison to the X, Y and Z coordinates of the pathological to be examined To determine tissue. The introduction of the puncture needle for biopsy with the help a carefully positioned needle guide in the direction of the site of the pathological Tissue could only by additional stereotactic radiographs be checked.

Mammograms are taken while the patient is standing in front of her X-ray device sitting, can make an inevitable movement of the patient and resulting in inaccuracy. Traditional tables that the Pati wear entin in a prone position, the chest by a suitable Öff As a rule, hanging in the table usually requires the patient to put his arms on lift, causing the arm muscles are stretched, the breast tissue torn or is twisted and again inaccuracies are caused. Additionally call The relatively flat and hard tables often unnecessarily stress and strain on the The patient's joints and vertebrae give rise to unwanted restless movements conditions.

US 5,018,176 A, which forms the starting point of the present invention, of discloses a device for stereotactic mammography examination, a pivotable image arm with an arranged at one end X-ray source au has. The device comprises a further pivotable arm, on which two Pressure plates are mounted to each other displaceable to a breast to be examined to be able to pinch. This second arm also carries a likewise displaceable mounted image receptor in the form of a cassette containing an X-ray film.  

For the performance of stereotactic recordings is a to be examined Breast of a patient with essentially horizontal extension between the front clamped said printing plates. Subsequently, two shots of the Chest with different pivoting positions of the X-ray source with stationary image Receiver recorded on the X-ray film. This is by one of the X-ray Source assigned aperture and possibly by an additional mask the necessary Offset of the two images on the X-ray film ensured. From the two Recordings can then be determined the position of diseased tissue. adversely is that the angle of incidence of the X-ray on the X-ray film of the Schwenklage the X-ray source depends, so that the evaluation of the X-ray images is difficult, and that the angle of incidence of the X-radiation on the X-ray film depends on the pivotal position of the X-ray source. This complicates the evaluation and leads to distortions as well as to a worsening of the resolution. A further disadvantage is that the known device a defined pinching the to be examined breast essentially only from below and above a standing Pa tientin, so that the examination and biopsy options, in particular in lateral tissue changes are limited.

US 4,727,565 A discloses a similar device, but in which a festste Hende, not pivotable pressure rail is provided.

US 5,056,523 A discloses a device for stereotactic mammography investigation. It is only indicated schematically that the X-ray source in under different positions is adjustable, with no indication can be found in wel cher way, the X-ray source and the X-ray film are arranged and positio can be defined.

DE 33 44 647 A1 discloses an X-ray diagnostic device with a tiltable Pati ducks stock instead. An X-ray source is from a substantially vertical to held upwardly extending support such that the x-ray source to a horizontal Axis is pivotable. In contrast, is also on the bottom of the Patientenla gerstatt an image pickup device fixed. Depending on the tilting position of the patients tenlagerstatt to a horizontal, parallel to the pivot axis of the X-ray source Axis is the X-ray source by means of a motor adjustable so that a central beam of the X-ray source to the center of an image receptor of the image pickup direction is directed. A particular disadvantage here is that around a horizontal axis  tiltable patient storage with arranged above the patient's storage Röntgen gene source and arranged below the patient's storage only image receiver a very limited range of angles between X-ray and to investigate allowed body parts.

The present invention has for its object, devices for stereotak To provide a mammographic examination, which has a particularly high accuracy in the localization and biopsy of suspected breast tissue of a patient enable.

The above object is achieved by a device according to claim 1 or 26. Advantageous developments are the subject of the dependent claims.

The table according to the present invention for a mammogram in Bauchla In particular, genposition makes it possible to comfortably carry the person lying in prone position Patient, by a leading edge part is removable, so that the arm and shoulder of the Pa tientin can be lowered into a more normal position, which makes the uncomfortable patient's involuntary movements to a minimum and the patient during the procedure in a normal and relaxed buttocks position is left. Additionally allows a centrally located, concave body Well designed in these tables, the X-ray examination of a ma ximal volume of breast tissue.

Furthermore, the central, concave body cavity, which accommodates the breast Opening surrounds, arranged in the middle of a table that is longer than normal, on each end has an extendable footrest and from one opposite to the acceptable front edge portion arranged rear base is worn. The Röntgen genröhre and the guidance of the puncture needle for biopsy thus enable a Access to the patient's drooping chest from any angles an angular range of more than 360 °.

With the present invention, the precise positioning of the puncture needle for the biopsy continue with the help of an electronic image processing with X-ray irradiated tissue achieved by charge storage elements or CCD's are used. Furthermore, a computer processing software ver which has been developed to increase the contrast sharpness between parts of the image  increase the particular structures of the diseased tissue of interest show change. This image processing system based on CCD (CCD images generating arrangement or CCD imaging system called) has such Advantages in the presentation and differentiation of non-palpable tissue changes ments that the contrast resolution and the sensitivity of the system that the conventional screen or X-ray film mammography, so that it often an accurate diagnosis of ambiguous findings without the need a biopsy allowed. The skills in the presentation will continue through electronic image processing techniques that improve the contrast. Delays resulting from film development and evaluation are caused by the System according to the invention eliminated, so that an immediate check of the correct Placement of the puncture needle for the biopsy is achieved, whereby the complaint of the patient during this critical phase of the procedure.

This almost real-time image processing of the stereotactic Röntgen genaufnahmen and their computer processing are preferably by opti This system facilitates in the position that is normally the X-ray film cassette is taken, is arranged. The preferred optical system has a phosphor screen exposed to the incoming x-ray radiation is who has gone through the breast tissue. That of the phosphor screen through the incident X-ray generated image is reflected by a mirror surface flexed, which is formed by a membrane reflector, which is an extremely thin Layer of nitrocellulose of selected optical quality, which has a Thickness is of the order of 5 to 9 microns and like an eardrum stretched over a black anodized, flat metal frame and on the precise lapped edge of the frame is attached. The X-ray radiation passes directly through This thin film to the phosphor screen, while the phosphor screen witnessed visible light from the bottom of the film directly towards the Camera lens is reflected. This is a reflective coating of metalli scheme material, such as alumintum stlicat, on the underside of the thin film ange ange introduced. Suitable coatings produce one depending on the wavelength Reflectivity of up to 60%. In a preferred embodiment, the Surface of a flat second mirror, the reflected image, causing a com pakt folded optical system is created, which expediently in one Light-tight housing is installed, which has little more space than the conventional X-ray film cassettes and associated film holding elements needed. A preferred  Camera is cooled using the Peltier method and includes a rectangular CCD format with 1000 or more dots along each vertical one Page.

The comfortable table for carrying a patient in prone position with a Minimum disturbance of the normal breast shape works with the stereotactic Röntgen genprojektionssystem together, which is attached directly under the table. If it is desired, the folded CCD imaging system replaces the normal X-ray Filmkassette and the unique software improves the contrast and sharpness of the resulting image, obtained in near real time. According to the invention the image receptor and the x-ray tube are on the same angularly movable, Fixed C-shaped arm, so as to ensure that the X-ray image is always sinking is right to the optical axis of the incoming X-radiation. That's it it is possible for a bucky grid to keep all of its lattice planes permanent aligned with the X-ray source, causing stray side scattered radiation is minimized and generates X-ray images with maximum sharpness and clarity who the.

In particular, a highly useful table for holding a patient in Prone position for a mammographic examination and an effective stereotactic Mammography system made up of the discomfort and psychological problems minimizing patient stress while providing highly accurate localization and puncture for a biopsy of the breast tissue to be examined is made possible so that surgical procedures can be avoided in large numbers.

Another aspect of the invention is to provide such devices which expose the breast for a mammographic exam while at the same time their undisturbed orientation as well as an optimum of comfort and relaxation for ensure the patient during the procedure.

Another aspect of the invention is to provide such devices which allow accurate guidance of the puncture needle for the biopsy procedure by an electronic image processing in near real time and a review of the Puncture needle positioning is applied so that the delays eliminated By loading, exchanging, unloading, developing and evaluating the Film cassette arise.  

Another aspect of the invention is to provide such devices which make it possible to stereotak a maximum volume of breast tissue of the patient image, so that a three-dimensional location of internal pathological Ge changes in the tissue or other internal sites requiring a surgical examination need, is possible.

Another aspect of the present invention is a folded optical To provide CCD system that takes advantage of a large CCD device to Pictures of the examined tissue of the patient with very high resolution to enable.

Finally, another aspect of the present invention is to be processed To specify techniques for digital x-ray images, the window and Schwellenma nipulation, an analysis of a section of interest, filter and edge ver make use of improvements to enable definitive X-ray diagnosis in many cases chen.

Other aspects and advantages of the present invention are in part obvious and are partially described below. Accordingly, the present invention the design features, the combinations of various Elements and the arrangements of parts based on examples of the Konstruktio will be shown below.

For a better understanding of the characteristics and aspects of the present invention Reference is made to the ensuing detailed description with reference to the appended claims Drawing referenced. In the drawing shows

Fig. 1 is a perspective view of an apparatus for mammography investigations with a table for supporting a patient in the prone position,

Fig. 2 is a perspective view from the side of the table shown in Fig. 1, showing the pedestal, pedestal and angularly movable C-shaped arm showing the X-ray tube and the image receptor as well as the separate pressure rail which supports the printing plates and the Carrying a deli,

Fig. 3, where X-rays are irradiated onto the underside of the breast in the direction of the right end of the table in a front view of the table shown in Fig. 1 for supporting a patient in the prone position with maximum elevation with respect to the floor,

FIG. 4 is a schematic plan view of the table illustrating what range of x-ray tube adjustments is made possible by the construction of the rear socket unit . FIG.

Fig. 5 is a plan view of the table shown in Figs. 1 to 3, with the C-shaped arm positioned to radiate X-radiation to the side of the patient;

Fig. 6 is a schematic front view of the same table, the C-shaped arm-för X-ray radiation that is emitted in the direction of the left end of the table is positioned,

FIGS. 7A, 7B and 7C correspond to one another, successive partial plan views showing the pressure rail, which carries the breast-clamping printing plates and the needle guide in a fixed position beneath the table, while the underlying C-shaped arm, the tube, the X and the Image receiver carries, is moved in different angular positions,

Fig. 8 is a schematic representation of the stereotactic Mammografiever procedure of the present invention, in which the beam paths of the X-ray radiation to be examined by a tissue change and a reference point on the printing plate for two angularly adjusted positions of the X-ray tube hood are compared when the image receptor together with the X-ray tube hood turning on the C-shaped arm,

Fig. 9 is an enlarged schematic partial view showing the lower end of FIG. 8 with greater accuracy,

Fig. 10 is a schematic representation of the two X-ray images generated by the image receiver of the same two source settings,

Fig. 11 u. FIG. 12 shows schematic representations of the X-ray pathways for two stereo-tube settings at different angles, using a folded CCD optical imaging system employed at the location normally occupied by the X-ray film cassette used in film mammography, but with the reference in FIG 13 to 17 illustrated digital optical CCD imaging system rotates the Fig., together with the X-ray tube,

Fig. 13 is a schematic plan view of the prior art conventional stereotactic mammography method showing that the X-radiation is incident at angle of incidence significantly different from the normal angle of incidence so that undesirable image degradation occurs when the image receptor is stationary.

Fig. 14 is a schematic view showing the stereotactic images that are applied to identify the coordinates of interest pathological lesion with the example shown in Fig. 13 imaging system,

Fig. 15 is a top perspective view of the folded optical system used in the stereotactic CCD imaging system shown in Figs. 11 and 12 with a portion of the light impermeable housing removed to show the arrangement of the various components of the optical system to show,

Fig. 16 is a top plan elevational view of the diaphragm mirror used in the optical system shown in Fig. 15;

Fig. 17 is a side view of the same membrane mirror,

Fig. 18 is a schematic representation of the patient's compressed breast image on a phosphor screen of the optical system, where a focused image is directed at the CCD sensor and the imaging processor computer processes the CCD output signals for display on the monitor screen is carried out,

FIG. 19 is a detailed schematic diagram of a preferred embodiment of a CCD camera used in the optical system shown in FIG. 15. FIG.

Fig. 20 is an overview block diagram of the electronic system used for converting the digital information from the CCD camera into mammographic information displayed on the screen controlled by the associated computer;

Fig. 21 is a detailed block diagram of the illustrated digi tal control logic unit in Fig. 20,

FIG. 22 is a detailed block diagram of the analog signal processing unit shown in FIG. 20; FIG.

Fig. 23 is an overview of the CCD camera and the associated electronics and

Fig. 24 is an illustration showing the number of dots of a typical image each having certain brightness values.

In the illustrated preferred embodiment, three main components or sub-assemblies are included. These are the adjustable and versatile table for holding a prone patient shown in Figs. 1-7C, the novel folded CCD optical imaging system shown in Figs. 11, 12 and 15-17, and Figs Image editing system and the screen system for displaying the data that enable high resolution and image representations in near real time in the Syste invention men, as shown schematically in Fig. 18.

A patient-carrying table 21 has a platform 22 on which the patient rests in a prone position supported by a rear pedestal 23 which is upstanding from the posterior portion of a pedestal, as shown generally throughout FIG . The pedestal 23 preferably has a device for raising and lowering the table within certain limits, which serves the convenience of the patient and the operating personnel.

A carrier 26 protrudes beyond the lower part of the pedestal 24 from the front surface of the pedestal 23 , which is formed so stable that it can carry a win kelbeweglichen C-shaped arm 27 . The arm 27 is in the form of a letter C on its back, with the x-ray source or mammography tube hood 28 attached to an upstanding end. The axis of rotation 29 about which the C-shaped arm 27 is rotatably mounted for rotation relative to the carrier 26 is located close to the opposite upstanding end of the C-shaped arm 27 . This upstanding end comprises either an X-ray film cassette 31 or a folded CCD optical sensor system 32 enclosed in a light-tight housing and shown schematically in Figures 11 and 12 and also in the perspective plan view of Figure 15.

As shown in Figs. 1 to 3, carries an upper part 33 of the base 23, the table platform 22 at its upper end and the carrier 26 at its lower end, wherein the upper part 33 is a vertical movement of one in Fig. 3 Asked raised position down to a lower in Fig. 1 Darge presented position in which the carrier 26 is close to the lower set 24 . This vertical adjustment movement is made possible by pushing together the upper part 33 on an underlying lower part 34 of the base 23 , as shown in Fig. 3.

Another adjustment of the system is made possible by a separate verti cal setting of the carrier 26 relative to the upper part 33 .

Ideally, the tube cap 28 is arranged in its uppermost setting 28 A in a recess 49 formed on the underside on the table platform 22 ( FIG. 3), the image receiver 36 being attached to the opposite end of the C-shaped sleeve 27 either the X-ray film cassette 31 or the optical system 32 carries and is preferably arranged close to the underside of the table 22 , as shown in Fig. 3. This arrangement serves to bring the x-ray beam and the image receptor as close as possible to the thorax of the prone patient with face directed to the platform 22 .

As shown in Figs. 1, 4 and 5, in the central part of the platform 22, a central opening 37 is arranged, which receives one or both breasts of the patient so that they hang down through the opening 37 when the patient with the Face is aimed at the platform. Since the Bildempfän ger 36 is designed to be relatively thin, as shown in FIGS. 3 and 5, and since it is located close to the axis of rotation 29 about which the C-shaped arm rotates, allows the rotational movement of the C-shaped Poor 27 about the axis 29 , that the image receptor 36 can be placed between the breasts of the patient or on the underside of a breast by minor adjustments at the position of the axis 29 relative to the carrier 26 are performed.

A fixed first pressure plate 53 and a second pressure plate 38 which is back and forth against the pressure plate 53 , above the C-för shaped arm 27 on an independently rotatably mounted pressure rail 50 be strengthened. The second pressure plate 38 may be considered a biopsy printer because it has both a transparent portion that allows X-rays to pass toward the patient's chest and the image receptor 36 , and has a central needle aperture. The pressure rail 50 additionally has a mechanism for receiving a needle guide 39 in order to carry out a puncture biopsy without releasing the chest from the pressure bar. This ensures that the coordinates of the lesion to be examined, which have been determined during the original stereotactic measurement, are maintained during the introduction of the puncture del so that the same coordinates of the tissue to be examined are achieved.

The preferred embodiment of the table 22 illustrated in Figs. 1-6 has as another useful feature a centrally located concave body cavity 35 surrounding the centrally located aperture 37 . The recess 35 allows the head, shoulders and body of the prone lying patient to be worn in a comfortable manner, the hips and legs of the patient either to the right or to the left over the little hö ago designed parts of the table 22 protrude, if necessary also footrests 43 and 44 may have.

The central position of the opening 37 and the footrests 43 and 44 at both ends of the table 22 or 22 A allow the 210 ° range of the possible X-ray imaging angle, as shown in FIG. 4, to be exploited twice So a range of about 420 °. In the prior art, no mammographic table is known that offers such a wide range of imaging angles.

The slight elevation of the patient's hips through the depression 35 maintains the normal relaxed curve shape of the patient's spine, while the maximum possible volume of breast tissue is suspended through the X-ray examination opening 37 . In addition, it allows the slight increase in the ends of the table 22 outside the centrally disposed Ver recess 35 that the arranged at the bottom recess 49 which surrounds the opening 37 , a vertical space for the upper end of the X-ray tube hood 28 below the table 22 releases , Therefore, the focal point FP of the x-ray source can be raised to coincide tangentially with the lower edge of the aperture 37 so that the desired exposure of a maximum volume of the patient's suspicious breast tissue to the examination is possible.

The front edge of the platform 22 adjacent to the opening 37 and opposite the base 23 is preferably in the form of a removable plate 41 , so that the radiologist and technician have unobstructed access below the platform 22 , and so that the patient's arm can pass through Removing the Plat te 41 opened space ( Fig. 4) can be lowered. As a result, the shoulder of the patient is conveniently lowered to the level of the opening 37 ( Figure 3) and any twisting or stretching of the chest hanging from the opening 37 is reduced to a minimum.

Various positions of the tube cap 28 , (which are adjusted by an angular movement of the C-shaped arm 27 along a circularly curved line 42 , as shown in Fig. 4) are shown in Figs. 3 to 6 Darge presents. In the outermost tube hood setting 28 B, shown in FIGS. 4 and 5, the X-radiation directed on the axis 29 hits a diseased tissue change from the outer side of the right breast or from the middle side of the left breast, when the patient with the head in Direction of the right end of the platform 22 is located, as shown in Fig. 3. The footrest 43 at the left end of the platform 22 is preferably withdrawn to support the patient's legs in this position, while the footrest 44 at the right end of the platform 22 preferably in the direction of the table end in the ge dashed line in Fig. 4 shown Position 44 A is inserted. When the patient's head is located to the left of the axis 29 ( FIG. 4) and the footrest 44 is extended to its solid line position at the right end of the platform 22 , the X-radiation radiated from the tube hood position 28 B hits the outer side of the platform left breast or the middle side of the right breast. In each of the axial positions, 28 C near the right end of the platform 22 or 28 D near the left end of the platform 22 , the X-radiation hits the breast either from above or below, while the image receptor 36 is placed on the opposite side of the breast is and currency rend the pressure plates 53 and 38 ensure that the patient is in a comfortable position so that there is no risk of unexpected movement currency end of the process.

In most cases, the X-ray tube hood 28 , which radiates X-radiation at the patient, will be located at the end of the platform 22 where the patient's head lies, while the image receptor 36 and the first pressure plate 53 are located on the underside of the drooping chest and while the movable second pressure plate 38 is disposed on the top of the breast. Both pressure plates are mounted on the pressure rail 50 , which, if necessary, carries the needle guide 39 on the upper side of the chest. However, if the diseased tissue change near the bottom of the breast, the reverse orientation for a minimal psychological burden on the patient is preferred, as shown in Fig. 3, wherein the needle guide 39 and the movable second pressure plate 38 on the underside of the chest is arranged and wherein the X-ray tube hood 28 is disposed behind the movable union second pressure plate 53 on the upper side of the breast. In this setting, the entry of the puncture needle to the biop enables it, via the needle guide 39 attached to the movable second pressure plate 38 , to insert a minimal path length in the underside of the breast tissue for access to the diseased tissue change. This setting may be preferred by many patients to ensure that any scar is due to the needle puncture on the underside of the breast, where it is less visible bar.

Two further tube cap positions 28 E and 28 F are also shown in FIG. 4. These positions are each offset by approximately 15 ° in and counterclockwise, which are typical angular adjustments for stereotactic mammographic studies. However, if necessary, clotting gere angle adjustments, for example, in the size of 10 °, on each Be te a longitudinal axis 46 of the platform 22 can be used, so as to ensure that the stereoscopic images both fall on the desired part of the image receptor. This can be either an X-ray film in a film cassette 31 or the electro-optical imaging system 32 , which is shown in the figures. The stereoscopic shift of the image of the diseased tissue change may possibly arrange this image in the outer area of the entire imaging area, if there are other than abnormal orientations of the diseased tissue, and for this reason, a lower bilateral shift of the positions 28 E and 28 F may be indicated.

When the film cassette 31 is used in the image receptor 36 in the stereotactic mammography examination, the cassette 31 may be provided with a film position shift lever as shown in Figs. 7A to 7C. A movement of this lever shifts the position of the film cassette such that the stereo images at plus 15 ° and minus 15 ° angular displacement of the axis 46 side by side on the X-ray film are arranged. While the patient remains on the platform 22 and while the movable second pressure plate 38 remains in position, the cassette may be removed, the film developed and evaluated to determine the current coordinates of the diseased tissue to be examined for punctional biopsy. When the needle guide 39 is in position and when the puncture needle is inserted to the predetermined location of the tissue to be examined, a new film cassette 31 can be mounted on the image receiver 36 and two further stereo collations can be taken to ensure that the tip of the puncture needle is at the desired location in the tissue to be examined. The Ent remote and the development of this second cassette to check the Po position of the needle tip thus allows any necessary fine readjustment so that the puncture biopsy can be terminated immediately afterwards.

The X-, Y- and Z-axis adjustment of the needle guide 39 relative to the patient's breast tissue is Runaway leads by linear motorized Ver, which are attached to a switching carriage 45 , which in turn is linearly mounted on the pressure rail 50 , the rotatably on Carrier 26 above the rotatable, the tube cap bearing C-shaped arm 27 is fastened be. A shift knob 48 , which cooperates with a timing belt or endless chain drive, moves the carriage 45 and the movable second pressure plate 38 to a position where the patient's chest 52 is compressed by touch, with the chest 52 lightly but firmly against the patient firmly set first pressure plate 53 is clamped. If an accurate puncture biopsy is necessary, the X, Y or Z control buttons on the carriage 45 allow the user to adjust the needle guide 39 to be biopsied according to the coordinates of the diseased tissue that is present in the stereotactic tissue X-ray examination have been determined.

For an appropriate record the X-axis is horizontal in Rich direction of the base 23 , the Y-axis vertically in the direction of the patient and the Z-axis horizontally parallel to the table platform 22 in the direction of the tubes hood 28th The pivot point at which the axis of rotation 29 intersects the XZ plane passing through the focal point FP of the source is taken as the origin or zero point for the X, Y, and Z values.

If the CCD-electronically enhanced optical system 32 is used instead of the film cassette 31 , much less time is required to complete the entire process. For example, the above-described stereotactic procedure with two X-ray film cartridges usually requires between 20 and 70 minutes, during which time the patient must remain in the same position face down on mammogram. With the electronic imaging system used in the preferred embodiment of the present invention, the digital imaging data received and processed by the system, as shown schematically in FIG. 18, allows mammography, puncture needle positioning, needle position verification by means of In any event, X-radiation and puncture biopsy should be completed in a period of 1 to 2 minutes, certainly within a time that is far less than 20 to 70 minutes normally required with conventional X-ray film cassettes in stereotactic mammography examinations. By minimizing the amount of time the patient is forced to remain in the same prone position, the comfort and relative immobility of the patient is improved, thereby minimizing inaccuracies that are unavoidable when a patient is over a long period of time Duration must be in the same position.

In addition to the very short duration of time required by a puncture biopsy procedure when applying a digital stereo CCD imaging technique, there is another important advantage achieved in the inventive prone tomography tomography examination table. As shown in Fig. 4, the table 22 projects forward and is supported in a cantilever manner along its trailing edge by the rear socket 23 . The wide open space below the table 22 provides much room for the rotational movement of the x-ray tube hood 28 over a continuous range of positions that include those positions shown in the figures: the left longitudinal positions 28 A or 28 D (FIGS . 3 and 4) ); the stereochemed positions 28 E or 28 F ( Figure 4); the lateral position 28 B ( Figures 4 and 5) and the right longitudinal position 28 C ( Figures 4 and 6).

Thus, for a patient lying on her feet on the left foot support 43 , a range of 180 ° plus 15 ° plus 15 ° or 210 ° of the tube hood positions on the right side is accessible. If the same patient is lying with her feet on the right foot support 44 , the entire range of 210 ° of left side adjustments is equally available. Therefore, for the same patient, not only is there a 360 ° range, but in fact a 420 ° range of tube hood positions is available.

The longitudinal cross-section of the table 22 in kink wing shape, as best seen in Figs. 3 and 6, has a flat, conical, centrally located recess 35 which surrounds the opening 37 , allows a maxima len comfort for the patient and excellent positioning of the chest to the examining pendent and also allows the additional part of the whole 420 ° area. This is ensured because both, slightly raised Knickflügelenden of the table 22 recesses 49 on the Un underside form ( Fig. 2, 3 and 6) and because the X-ray tube cover 28 can therefore be moved over the entire front 210 ° angle region of the opening 37 with its upper end projecting into the recess 49 . The exit opening 55 of the x-ray tube hood ( Figure 1) is located several inches below the topmost end and emits the x-ray along a beam axis G = SID ( Figure 8) so that the x-ray traverses the axis of rotation 29 and perpendicularly impinges on the image receiver 36 , brushing the lower edge of the opening 37 . This allows a mammographic study of the maximum volume of breast tissue over the continuous range of imaging angles, as previously described, with a large working range available to the radiologist and technicians below the table 22 as shown in Figs 3 is shown, for example.

Stereotactic imaging system

The stereotactic imaging of breast tissue using X-ray radiation passing through the compressed breast of the patient from two different source positions to produce two stereo images on X-ray film is described in detail in the article by Bolmgren, "Supra," in the American Journal of Roentgenology in July 1977 and also in US-A-4,727,565 and US-A-4,930,143. Fig. 13 now shows a schematic representation of the prior art stereotactic X-ray mammography with two source positions with a diseased tissue change 51 in the tissue of the patient's breast 52 between a fixed first pressure plate 53 and an adjustable, movable second pressure plate 38 , both are permeable to X-rays, compressed.

Now, when the image receiver 36 is stationary, the first printing plate 53 preferably coincides with the position of the image receiver 36 , as shown in FIG. 13, and thus has the nearest surface of the receiver 36 .

When the image receptor 36 of the present invention is mounted on the C-shaped arm 27 for rotational movement with the x-ray tube hood 28 , as shown in FIGS. 2, 3, and 6 through 12, the image receptor 36 is spaced far enough behind the axis of rotation 29 , to provide enough space for the required angular movement.

Another advantage of attaching the image receptor to the C-shaped arm results from the utility of bucky grids with divergent tilted plates to allow x-rays directly from source FP to pass through while blocking off laterally scattered or secondary x-rays which would otherwise reduce the sharpness of the picture. When the Buchy grating is attached to the image receiver 36 which rotates with the C-shaped arm 27 carrying the tube cap, the divergent plates are aligned with the source FP in all of the set stereo positions shown in Figs. 7A and 7B. On the contrary, a stationary Bucky grating in front of the imaging plane of the image receiver used in the prior art in Fig. 13 may have its plates aligned with only an x-ray source setting. As a result, these plates interact with some of the desired X-rays coming directly from the source, coming from other distorted source settings, so that the usefulness of the Bucky grating is significantly reduced.

The determination of the X, Y and Z coordinates of the suspect pathological tissue is carried out by calculating the equations for the inclination of the X-ray path which pass through the diseased tissue and through a reference point 40 disposed on the first pressure plate 38 to a first image level for the first source position S1 or 28 E ( FIGS. 4 and 8) and to a second image plane for the second source setting S2 or 28 F.

In Figs. 8, 9 and 10, the coordinates of the suspicious tissue changes are 51 X, Y and Z. Points 1 and 2 are the Y and X positions of the image of the reference hole 40 on the left image surface in Fig. 10 he will testify if the source is at S2 or at 28 F. Items 3 and 4 are the X and Y positions of the image of the hole 40 on the right side of the image, which is generated when the source is at S1 or 28E . Points 5 and 6 are the images of the suspicious tissue change 51 in the two image parts of FIG. 10.

This method is based on the equations of the two sources. to-image lines for the two images of diseased tissue change. The intersection of the two lines then gives the X, Y, and Z coordinates on the X-Y, Y-Z and X-Z planes.

The diagram in FIG. 8 shows the XZ plane in a view from below. The pivot point at which the axis of rotation 29 abuts through the XZ plane is used for the evaluation as a zero point for both X and Z values.

The diagram in Fig. 9 is an enlarged view of the area of the same diagram around the fulcrum.

The source-to-image lines for the image generated when the tube hood source is in the left-hand position (minus 15 °) represented by S1 or 28E in the other figures are represented by the following equations:

in which
G = SID, source-image distance,
M = distance from the fulcrum shown to the images E, F of the reference hole 4 (see FIGS. 8, 9 and 10)
B = distance between the image of the reference point (point 3) and the image of the pathological tissue change (point 6).

The source-to-image lines having a source in the right half (or + 15 °), position S2 or 28 F, are represented by the following equations:

Dissolve for Z: (Equation 1) = (Equation 2)

The height (when applying the same methods to the -15 ° image)

Resolution to X

After that for Y

In Figs. 8, 9 and 10 are

K = movie shift (74.5 mm) G = SID (743.0 mm) FPD = focal point - pivot (661.5 mm) R = shift of the focal point = FPD sin 15 ° (171.2 mm) AL = L <I = FPD cos 15 °

The digital imaging system

The main internal components of the folded optical system 32 are schematically in Figs. 11 and 12 and in the cutaway perspective view in Fig. 15, in which the X-ray transmitting cover plate 60 , which forms the nearest or front wall of a housing 54 of its support frame 56 has been removed to show the internal structure within the half of the housing 54 . Similarly, an upper housing wall 57 is removed from its upper support frame 58 , whereby also the internal structure of the optical system 32 is shown. Partially broken parts of the housing wall 57 and the cover plate 60 are shown on the left side in Fig. 15.

As shown in FIGS. 11 and 12, the radiation emanating from the X-ray tube hood 28 successively passes through the X-ray radiation through letting, adjustable, movable second pressure plate 38 , the patient's breast 52 , the fixed first pressure plate 53 and then a thin membrane 59 . This is a film of high tensile elastic membrane material such as nitrocellulose. Its thickness varies, for example, between 5 and 9 microns. It is stretched over a flat metal frame 61 ( Figure 15) like an eardrum and connected to the precisely lapped edge of this frame. The thin membrane film is virtually transparent to X-radiation which passes directly through the film to impinge on the underlying phosphor screen 62 which is fixed on the image plane to the rear wall 63 of the housing 54 . Index marks which are opaque to X-rays and which may be in the form of a reticule, for example, as shown in Fig. 14, are arranged at points B1 and B2 on the X-ray transmissive solid first printing plate 53 known in the art is firmly connected to the image receiver shown in Fig. 13. These index markers are depicted as illustrated with the crosses B1 and B2 in FIG. 14, which is an elevational view of the various points along the X-ray beam path through the system as shown in FIG . Therefore, the point S1 in FIG. 14 corresponds to the vertical projection of the source position 28 E onto the image plane, the source position 28 E representing the first angular displacement of the tube cap 28 , as illustrated in FIGS. 4 and 13. In the same way, the point S2 represents on the image plane, the vertical projection of the second Röh renhaubenquellenposition 28 F, as is also provided in Figs. 4 and 13 represents.

The X-ray beam from point 28 E through the X-ray impenetrable marker B1 is imaged onto the point P4 on the image plane, while at the second source position 28 F the beam path of the X-ray radiation through the index mark B1 is imaged onto the point P2, as shown in the elevation view in Fig. 14 is shown. In the process, they intersect at the beam paths of the x-ray radiation which are imaged onto the image plane at the marking point B1, as illustrated in FIG. 14. In the same way, the index mark B2 is determined by crossing the vertical projections of the ray paths of the X-rays S2P1 and S1P3.

As also shown in Fig. 14, the beam path of the X-ray radiation from the source S1 produced by the diseased tissue change 51, the vertical projection of the beam path S1L1 on the image plane and the intersection of this projected line with the line S2L2 indicates the position, at which the diseased tissue site in the stereoprojection in Fig. 14 appears. Once the coordinates of these points S1, S2, B1, B2, L1 and L2 have been determined on the image plane, this data can be digitally recorded and processed to obtain very accurate X, Y and Z coordinates for the current position of the diseased To get tissue change.

This digital data handling is facilitated by the optical system 32 shown in FIGS . 11, 12 and 15-18. This optical system 32 has a arranged on the underside of the membrane mirror 59 coating, which serves as a mirror and the image of the image plane representing the phosphor screen 62 is reflected toward a second mirror 64, the reflected image of the phosphor screen 62 to a lens 66 of a CCD -ausge equipped camera 67 reflected.

If now the viewing direction is directed from top to bottom in Fig. 15, therefore, the image of the phosphor screen 62 is reflected from the bottom of the membrane film 59 to the right to the angled mirror 64 , which then the image down in the direction of above The CCD camera 67 is directed lens 66 , as clearly shown in Fig. 15.

Advantageously, the reflective underside of the Mem branfilms reflects the image of visible light in the direction of the CCD camera, with any diffusion or loss through the transmission through the phosphor screen 62 can be avoided. Likewise, the diagonal arrangement of the film 59 necessarily requires a space between the phosphor screen 62 and the X-ray transmitting cover plate 60 . The phosphor screen 62 thus receives X-ray radiation, which extends from the tube head by the target, but is most secondary or scattered X-radiation which is generated inside the target, lost, so that a pure and sharp-fe image is formed on the screen 62nd

The camera operating in the snapshot mode integrates the image from the phosphor screen 62 , and at the end of the exposure time, the image is stored in computer memory. This procedure is performed for the X-ray image generated with a tube hood position 28 E at the source position S1, and is repeated for another exposure for a tube hood position 28 F at the source position S2. In this way, within two seconds, two stereo images can be obtained and stored in the computer. The user then places the images on the screen and, using a rollball (mouse), positions a cursor on the calibration marks B1 and B2 and the location of the diseased tissue.

Based on these cursor positions on the screen, the computer calculates the X, Y and Z positions of the diseased tissue change relative to the pressure plates 38 and 53 clamping the breast.

These X, Y and Z coordinates can then be used immediately for a puncture needle or core biopsy are used, with the needle guide for a steering the puncture needle for biopsy to the site of the diseased tissue ver change is used, whereupon recorded two more stereo images be to the exact positioning of the tip of the puncture needle at the To check the location of the abnormal tissue change. As alternative These pictures can also be used to one possibly to conduct necessary surgical intervention.

The thickness of the membrane film preferably falls in the range between 5 and 9 μm, in particular in the range of 6 to 7 μm, the uniformity of the thickness being very accurate and the surfaces of the film being parallel with an accuracy of two wavelengths of X-radiation per inch , An aluminum or silicon dioxide coating, which is attached to the underside of the membrane film, has a reflectance of more than 8%, with no holes visible to the naked eye, thereby ensuring the uniformity of the resulting CCD image. While normally the diaphragm mirror frames 61 are annular, the unique "D-shaped" configuration of the diaphragm mirror 59 and the frame 61 used in the optical system of the preferred embodiment of the invention has a particular advantage: a rectangular region 68 ; which corresponds to the area of reflection of the image of the phosphor screen 62 on the membrane film is uniformly smooth and flat over the entire surface and the circle segment of the frame 61 and comprises approximately 250 °, while a straight Kreisseh ne 69 , the D-shaped frame 61 closes, the remaining angle of about 110 ° encloses. In this way, this D-shaped frame 61 brings the critical area 68 very close to the adjacent chord 69 of Rah mens 61 zoom, as shown in Fig. 16. The circular tendon 69 is thus arranged very close to the upper housing wall 57 , as is apparent from Fig. 15 Lich, whereby the critical area for the imaging of the X-ray radiation, which is passed through the breast 52 of the patient, very close to the table platform 22 is brought. Thereby, the visible image of the phosphor screen 62 is generated directly adjacent to the upper housing wall 57 , which in turn is arranged vertically as close as possible to the chest of the patient. In this way, the maximum volume of the patient's breast 52 can be examined by mammography, with the x-ray radiation passing through the D-shaped membrane mirror 59 .

Figs. 7A to 7C, 11 and 12 show a preferred embodiment of the present invention in which the opaque housing 54 is independent of the fixed first pressure plate 53 and for a rotational movement about a rotation axis 29 , which is a little spaced from the fixed first Druckplat te 53 is arranged, together with the tube cap 28 is mounted on the C-shaped arm. Thus, the tube cap 28 and the housing 54 thus rotate as a unit from the position 28 E- 54 E in FIG. 11 to the position 28 F- 54 F in FIG. 12. A substantial portion of the patient's breast 52 may be in this manner in any position in the form of a wide image using almost the full width of the phosphor screen 62 , as shown in these figures. Once the CCD camera 67 has taken the image generated by the position 28 E or S1 X-ray tube hood, the C-shaped arm 27 can be rotated to the tube hood position 28 F and S2, so that again the entire width of the phosphor screen 62 for Reception of the second stereo image is available.

Fig. 11 and 12 show a second, characteristic for this embodiment table element. The X-ray opaque index marks B1 and B2 are the same as the reference hole 40 on the movable second pressure plate 38 and not on the fixed first pressure plate 53 arranged to ensure that the diverging, passing through the index marks beam paths in each source position to a useful Abbildungsbe rich of the phosphor screen 62 fall.

The optical system with digital CCD imaging

A preferred embodiment of a CCD camera 67 is shown schematically in detail in FIG . In this drawing, the lens 66 is supported by a lens holder 71 which is disposed on a front surface 73 of a Kameragehäu ses 72 . The front surface 73 has a translucent Fen ester 74 , behind which a CCD array 76 is disposed. The light focused through the lens 66 is directed to the focal plane by the fenter 74 , which coincides with the surface of the CCD array 76 . The array 76 is attached to a front side of a base 77 in the form of a "cold finger", the rear end of which is anchored to a cooling element 78 which is cooled by the thermoelectric Peltier method and which is attached to the rear side 79 of the camera body. wherein the heat exchanging ribs 81 protrude into the surrounding atmosphere. An annular printed circuit board 80 closely encloses the "cold finger" socket 77 so as to minimize resistance losses in the traces not shown in FIG. 19 which connect the CCD array 76 to the card 80 .

The CCD array 76 , which is disposed in the focal plane of the lens 66 , receives via the mirrors 59 and 64 the focused image of the light produced by the phosphor screen 62 . The array is scanned very fast to allow storage of the image in memory for manipulation, enhancement, and possible later examination without any delays necessary in the treatment of X-ray films.

As best seen in FIGS. 18 and 20, the computer and associated electronic system forming part of the entire digital mammography system include the computer 100 , a control unit 102 , a display unit 104 for displaying the mammographic information, and a disc drive 106 and a keyboard 108 which are ver with the computer 100 connected. As best shown in FIG. 20, the electronic system includes an interface card 110 and a graphics card 112 located in the computer 100 .

The details regarding the computer, video card and monitor that be used in the preferred embodiment of the invention, are listed in Table 1.

Table 1

Computer 100 IBM compatible personal computer with an Intel 80386 ™ or 80486 ™ processor, 12 to 16 MB RAM, and 200 MB hard disk space Graphics card 112 Trident Impact 3 ™ graphics card with 1024 × 768 pixels resolution and 8 bit brightness resolution per point Screen 104 Dotronix M2400 ™ 20-inch monochrome monitor with P104 phosphor, set to the vertical and horizontal sampling rate of the graphics card; analog input

A digital logic control unit 114 and an analog signal processor 116 form the entire control unit 102 . The digital logic control unit 114 generates various clock signals for transmission to the camera 67 which are used by the CCD array 76 . The output of the CCDs are amplified by a preamplifier 120 , so that a CCD output signal on a Buslei device 122 is generated for transmission to the analog signal processor 116 .

Fig. 21 shows a detailed block diagram of the Digitallogiksteuerungsein standardize 114 and provides the specific clock signals are generated 124, the synchronized samples, and data, the bus line between this module and the analog signal processor 116 on the output is transmitted 126 line on an output bus, as well, is A computer generated integration control signal is also shown, which is received by a main logic control unit 132 via line 130 .

The details of the analog signal processor 116 are shown in the detailed block diagram in FIG . As can be seen in FIGS. 20 and 22, an X-ray status signal indicative of the presence of X-radiation and generated by an X-ray detector 134 is provided on an input status line 136 .

As can be seen in general in FIG. 22, the CCD output signal applied to the line 122 is transmitted to an input amplifier 138 , from where it is switched to two sample and hold signals under the control of the synchronization and sampling signals. Units 140 is transmitted. From there, the CCD output signal is transferred to a differential amplifier 142 and buffer 144 so that it is transferred to a 12-bit analog digital converter 146 and so that the digital output of the CCD image is first-in-first-out. Memory (FIFO) 148 is transmitted. The output signal of the FIFO memory 148 is connected to the computer interface card 110 for display and image processing with the computer, so that the output signal via the graphics card 112 can be displayed on a screen 104 as a gangsbild starting, see Figs. 18 to 20.

FIG. 23 shows a detailed schematic representation of the camera 67 and the associated electronics, wherein the serial clock frequency signals transmitted by the digital logic control unit 114 via the bus line 124 represent. Furthermore, the output of the digital CCD data over the bus line 124 , the input of the information of the V-clock (parallel clock) on bus 124 and the base voltages generated by the digital logic control unit 114 and the analog signal processor 116 is shown.

Digital image processing

The entire imaging system illustrated in FIG. 20 generates an image of the mammography information on the screen 104 . To cope with this task, the digitized CCD data received from FIFO memory 148 (see Figure 22) on bus 150 is under the control of computer 100 , executing a computer program.

In general, the image of the mammographic information displayed on the monitor 104 has 512 × 512 points on a screen of 1024 × 768 points, each point having a brightness resolution of 8 bits or 256 brightness values. The present invention can also support a display of up to 1024 x 1024 dots. The brightness value of the CCD camera has a resolution of 12 bits or 4096 brightness values. Of course, this 12-bit brightness information can be displayed by the CCD camera with the aid of a graphics card and a monitor having such a high brightness imaging capability.

The CCD camera can output the data in a 512 × 512 dot array or in a 1024 × 1024 dot array. If a higher resolution array is used, the monitor 104 represents a 1024 x 768 dot area of the CCD data, typically covering 128 rows at the top and bottom of the CCD image, however, the image frame being viewed through the CCD image can be moved.

How digital image processing works

The computer program essentially performs Follow the steps below to get the mammographic information on the Display screen: (1) The program generates a 12-bit brightness formation for every point on the entire screen in which a dark field subtracted and ver with the particular CCD imaging device fixed fixed noise pattern is removed, (2) the computer program is divided the dark field with a white field of brightness, sometimes called "Flat Fiel ding ", so as to clear bumps in the X-ray radiation information as a result of nonuniform X-radiation illumination and (3) the computer program generates a brightness the histogram of the displayed data.

In addition, the digital image processing according to the invention allows a contrast enhancement which effectively narrows the brightness range or brightness window and also permits a shift of this brightness window within the range of brightness values for which a proportional gray scale scaling is set up. This means that the window is moved within the CCD brightness value range from 0 to 4095. This function is sometimes referred to as "windowing". Furthermore, in particular the contrast shown on the monitor 104 can be increased by reducing the displayed brightness values. For example, the brightness values from 1000 to 1511 can be represented as part of all brightness values from 0 to 4095. Thus, the 512 different brightness values (1511-1000 = 511) can be transmitted to the 256 different brightness values which can be displayed on the monitor 104 , wherein white stands for a brightness value = 1000 and black for a brightness value = 1511. All brightness values equal to or less than 1000 thus become white and all those equal to or greater than 1511 are represented as black. Of course, the brightness values generated by the CCO camera can also be displayed inversely on the monitor. For the above example, all brightness values equal to or less than 1000 would be represented as black, and conversely, the brightness values equal to or greater than 1511 would be represented as white. It should also be noted that a quick inversion of the data presented may help the user to detect phenomena that could not be detected by viewing the image in one polarity.

Windowing means that a range of values to be displayed is moved up or down in the range of 4096 brightness values produced by the CCD camera. In the above-mentioned example, this means that 512 different brightness values that can be displayed on the screen 104 , are pushed down to z. For example, they may include the brightness values of 70 to 581, or they may be shifted up to include, for example, the brightness values of 4020 to 4531. This combination of continuous control and windowing means a significant improvement in the diagnostic imaging of the CCD image data originally obtained from the camera.

Furthermore, a brightness histogram can be generated by the image processing system. This brightness histogram is then used in the method sometimes referred to as automatic grayscale scaling. In essence, this method analyzes the CCD image data to determine which brightness values have been obtained primarily for a particular image. For example, an image may have most points with brightness values in a range of 2000 to 3000. Typically, the distribution of the number of dots to particular brightness values has a characteristic bell curve, as shown in FIG . The system then determines that the majority of the brightness values of the points are predominantly between 2000 and 3000, and the system then displays only those values as gray levels on the monitor. Those points with a brightness value equal to or less than 2000 then shown as white, while the values of the points that are equal to or greater than 3000 are displayed as black. This method is therefore similar to the method of contrast enhancement, in which the brightness values to be displayed are selected.

The present invention further includes a convolution filter and a Edge enhancement, which affects the entire picture or just one Part of it can work. For the convolution filter can be a core that out a matrix size of 3 × 3 points or 5 × 5 points consists of each Be used around the point for which such a convolution filtering benö is taken.

Furthermore, the implemented program uses a table technique for the grayscale scaling associated with the screen brightness values , thus allowing the above-described brightness-to-gray scaling the image representation.

Other features include high pass filtering for sharper viewing of details as well as a low-pass filtering, for strong spatial noise to effectively remove the edge reinforcement for fast changing data allows.

Furthermore, the system according to the invention is capable of producing a "histogram Adjustment "and a" contrast stretch "similar to the above Convolutional filtering described these functions on the entire image or act only on a part of it, sometimes as interesting Be rich is called. The "contrast stretch" causes an extension of the Grayscale scaling in the region of interest, with the entire Be rich of representable grayscale only for this area of interest is used.

In the "histogram matching", the system re-displays the data of the area of interest so that the resulting data in each histogram bar has an equal number of brightness levels that have occurred. In other words, this means that, when looking at the brightness histogram of the region of interest after the histogram adjustment is applied, each bar of the histogram has the same height and does not have a bell-shaped curve shown in Fig. 24. Histogram matching enhances grayscale rendering for a particular image, making it easier to visualize abnormal details.

Finally, the stereotactic image processing described above uses a cursor mark in the displayed image implemented in the program. The position information available in digital form can be combined with the X, Y or Z control buttons ( FIGS. 6, 7) arranged on the carriage of the needle guide 45 , which are driven either manually or with follow-up drive, and zero-balance signals. which indicate the match of the calculated coordinates with the current coordinates. This combination corresponds to the manual calculation of the coordinates using a "digitizing tablet" having a grid system in the form of a film such as those used in computer trays to produce the same correspondence with the actual coordinates of the carriage of the needle guide.

The overall result is not just a di gitale information, but an overall improvement of In formations that increase the size of certain Areas, edge enhancement, contrast enhancement and distance artificially Licher interference associated with the CCD imaging sensors. In general, digital image processing provides the examiner Doctor with a much larger amount of information than previously used dete radiographic images using method.

Claims (30)

1. Apparatus for stereotactic mammography examination for the implementation of a stereotactically guided biopsy,
with a base ( 23 ),
image arm ( 27 ) mounted with an image-forming end, having a near end and a distal end rotatably mounted on a point located between the near and far end and rotatable on the pedestal ( 23 );
with an X-ray source having an X-ray focus, at the remote end of the image arm (27) arranged X-ray source ( 28 ),
with an X-ray-sensitive image receiver ( 36 ), which has a substantially planar, the image-receiving image area,
serving with one of the compression, a close and having a distal end and rotatable in a cylinder disposed between the proximal and the distal end point to the base mounted (23) pressure rail (50), wherein the pivot point of the pressure rail (50) with the pivot point of the Image poor ( 27 ) is axially aligned
with a at the near end of the pressure rail ( 50 ) arranged and along the pressure rail ( 50 ) back and forth displaceable first pressure plate ( 53 ),
with a carriage ( 45 ) arranged on the pressure rail ( 50 ) between the distal end and the first pressure plate ( 53 ) and displaceable along the pressure rail ( 50 ),
with a second pressure plate ( 38 ) carried by the carriage ( 45 ) and
with a biopsy needle guide ( 39 ) which can be positioned three-dimensionally and carried by the carriage ( 45 ),
wherein clamping of the breast ( 52 ) of a patient between the first pressure plate ( 53 ) and the second pressure plate ( 38 ) is possible independently of the rotatably mounted image arm ( 27 ),
characterized in that the near - end imaging arm ( 27 ) supports the image receiver ( 36 ) so that the first pressure plate ( 53 ) and second pressure plate ( 38 ) remain stationary with the breast ( 52 ) pinched while the x - ray source ( 28 ) and the Image receiver ( 36 ) together with the image arm ( 27 ) in the same angular direction about the axis of rotation are movable, and that the image arm ( 27 ) supports the image receiver ( 36 ) so that the image area we sentlichen perpendicular to the X-ray source ( 28 ) outgoing and running to the image surface X-rays.
2. Device according to claim 1, characterized in that a Bucky grating is arranged on the image arm ( 27 ) between the image receiver ( 36 ) and the X-ray source ( 28 ), that its divergent inclined plates substantially to the focus of the X-ray source ( 28 ) are aligned, and that the X-ray source ( 28 ) outgoing X-rays before impinging on the image surface of the image receiver ( 36 ) extend through the Bucky grating.
3. Apparatus according to claim 1 or 2, characterized in that a biopsy sienadelführung ( 39 ) on the pressure rail ( 50 ) for performing a puncture biopsy at the between the pressure plates ( 38 , 53 ) clamped breast tissue is ordered to.
4. Device according to one of claims 1 to 3, characterized
that a substantially flat, horizontal, the patient carrying platform ( 22 ) is provided, which is supported by means of a rear side member ( 26 ) through the base ( 23 ) and which has a free, not held leading edge and not ge held right and has left side ends, and
in that a centrally arranged in the platform ( 22 ), a breast ( 52 ) receiving opening ( 37 ) is provided for a through this opening ( 37 ) freely suspended Posi tioning of the breast ( 52 ) of the patient below the surface of the platform ( 22 ) is seen easily.
5. Apparatus according to claim 4, characterized in that
that the image arm ( 27 ) and the pressure rail ( 50 ) below the platform ( 22 ) are arranged, wherein the axes of rotation of the image arm ( 27 ) and the pressure rail ( 50 ) are arranged vertically and aligned with the opening ( 37 ), and
that the image arm ( 27 ) is C-shaped and is rotatable over an angular range of more than 180 °, wherein the X-ray source ( 28 ) in any of the unlimited number of available source positions in an area starting from the direction of the one side of the platform ( 22 ) via a from the rear base ( 23 ) ent distant side position to the direction of the other end of the platform ( 22 ) anord nenbar, whereby an arrangement of the x-ray source ( 28 ) in an adjustment range greater than 360 ° is made possible, wherein the Head of the patient is arranged either in the direction of the right end or the left end of the platform ( 22 ).
6. Apparatus according to claim 5, characterized in that a concave ge curved, flat, the body receiving recess ( 35 ) in the platform ( 22 ) is formed, which extends over the central region of the base ( 23 ) to the front edge , wherein the opening ( 37 ) is arranged centrally in the platform recess ( 35 ), in the middle between the right end and the left end.
7. Apparatus according to claim 5 or 6, characterized in that wide, flat, on the underside of the platform ( 22 ) arranged recesses ( 49 ) are provided, which the breast ( 52 ) receiving opening ( 37 ) and possibly the flat flanking the body receiving recess ( 35 ), and the tube hood of the x-ray source ( 28 ) has an upper end positionable in each of the shallow, lower recesses ( 49 ) above the plane of the aperture ( 37 ) receiving the breast ( 52 ).
8. Device according to one of claims 5 to 7, characterized in that a free access to the drooping breast ( 52 ) of the patient over a range of more than 180 ° is possible without being hindered by the rear socket ( 23 ).
9. Device according to one of claims 5 to 8, characterized in that a centrally disposed region of the front edge of the patient supporting platform ( 22 ) is designed as a removable segment for the formation of a cutout, so that a comfortable for the patient relaxed position of the Poor is made possible and so that the chest ( 52 ) freely and undisturbed below the platform ( 22 ) depends.
10. Device according to one of claims 5 to 9, characterized in that the platform ( 22 ) has two extendable and retractable footrests ( 43 , 44 ) for extension, that the footrests ( 43 , 44 ) respectively at one side end of the platform ( 22 ) and that the extended platform ( 22 ) is sized to support a prone adult female patient, with the patient's legs carried by one of the footrests ( 43 , 44 ) and, alternatively, in a reverse direction for carrying the patient dimensioned, the legs of the patient from the other footrest ( 43 , 44 ) are worn.
11. Device according to one of claims 5 to 10, characterized in that the rear base ( 23 ) is vertically retractable and retractable, so that the platform ( 22 ) is vertically adjustable in height.
12. The device according to one of claims 5 to 11, characterized in that the rotatable mounting of the C-shaped image arm ( 27 ) on the rear base ( 23 ) has a vertical adjustment device, the raising and lowering of the C-shaped image arm ( 27 ) in the direction of the vertical axis of rotation between lower Po positions and a highest position allows in which the upper end of the tubes hood ( 28 ) in one of the flat, located at the bottom recesses ( 49 ) above the level of the breast ( 52 ) receiving opening ( 37 ) protrudes.
13. Device according to one of claims 5 to 12, characterized in that the rotatable mounting of the C-shaped image arm ( 27 ) on the rear base ( 23 ) has a rotational movement of the C-shaped image arm ( 27 ) about the vertical axis of rotation in egg NEM Angular range approximately 210 degrees from a first setting on the rear pedestal ( 23 ) facing side of the longitudinal centerline ( 46 ) of the platform ( 22 ) near the first side end of the platform ( 22 ) forward below the leading edge of the platform ( 22 ) via a second adjustment on the leading edge opposite the pedestal ( 23 ) to a third position on the rear pedestal ( 23 ) side of the longitudinal centerline ( 46 ) of the platform ( 22 ) near the second side end of the platform ( 22 ) opposite to allows the first end and the extended platform ( 22 ) of a patient lying on it in prone position with her feet on one of the side ends, where wherein x-ray examination of any necessary side of the patient from any position of the x-ray tube hood ( 28 ) is feasible within the angular range of about 210 degrees.
14. Device according to one of claims 5 to 13, characterized in that the rotatable mounting of the C-shaped image arm ( 27 ) on the base ( 23 ) a Drehbewe movement of the C-shaped image arm ( 27 ) about the vertical axis of rotation between a pair of Source settings ( 28 E, 28 F) offset by the same acute angle from one axis.
15. Device according to one of the preceding claims, characterized in that
in that the image receiver ( 36 ) comprises a CCD imaging arrangement for converting the incoming X-radiation into a digital image output signal,
in that the CCD imaging arrangement comprises a hollow housing ( 54 ) arranged in the beam path of the incoming X-ray radiation and having an X-ray transmitting wall element ( 60 ) for receiving and transmitting the incoming X-radiation to the interior of the housing ( 54 );
in that the CCD imaging arrangement comprises a phosphor screen ( 62 ) arranged in the housing ( 54 ) in the beam path of the incoming X-ray radiation, which generates a visible light image on the surface closest to the incident X-ray radiation
that the CCD imaging unit comprises a CCD camera ( 67 ) which is aligned so that the CCD camera ( 67 ) receives the visible light generated by the phosphor screen ( 62 ), and
that between the permeable wall element ( 60 ) and the phosphor screen ( 62 ) diagonally arranged light membrane mirror ( 59 ) is provided, which is permeable in wesent union for X-radiation and at the rear or bottom carries a re flexing coating.
16. The apparatus according to claim 15, characterized in that the phosphor screen ( 62 ), the membrane mirror ( 59 ) and the CCD camera ( 67 ) are arranged in a compact, opaque housing ( 54 ) of an optical system ( 32 ).
17. The apparatus of claim 15 or 16, characterized in that a second mirror ( 64 ) is arranged such that the second mirror ( 64 ) the visible light from the nearest surface of the phosphor screen ( 62 ) from the membrane mirror ( 59 ) to the CCD Camera ( 67 ), wherein the optical system ( 32 ) is folded along an angled optical axis for improving the compactness.
18. Device according to one of claims 15 to 17, characterized in that one with the CCD camera ( 67 ) connected computer ( 100 ) for receiving the CCD camera ( 67 ) generated by the electronic signal and for generating a least one Part of the CCD camera ( 67 ) received electronic signal corresponding image signal and to the computer ( 100 ) connected device for displaying the image signal ( 104 ) are provided.
19. Device according to one of claims 15 to 18, characterized in that the computer ( 100 ) for generating an at least a portion of the CCD-Ka mera ( 67 ) received electronic signal corresponding image signal before a device for generating a proportional image at least a part of the electronic CCD camera signal and a device for modifying at least a part of the image signal.
20. The apparatus according to claim 19, characterized in that the device for modifying at least a part of the image signal is a Vorrich tion for changing the contrast associated with the image signal.
21. The apparatus according to claim 20, characterized in that the device for changing the contrast, a device for selecting a Range of brightness values of the electronic signal for which the Vor for modifying a proportional representation of at least part of the generated electronic CCD camera signal.  
22. Device according to one of claims 19 to 21, characterized in that the device for modification comprises a device with which the area of the Brightness values with respect to all possible values of the electronic CCD camera rasignals is displaceable.
23. Device according to one of claims 19 to 22, characterized in that the device for modifying a device for automatic determination the range of brightness values from the electronic CCD camera signal for which the image signal is again proportional to the electronic CCD signal provides.
24. Device according to one of claims 19 to 23, characterized in that the device for modifying comprises a device which displays the image signal the base of the adjacent area of the CCD-Ka corresponding to the image signal merasignals transforms.
25. Device according to one of claims 15 to 24, characterized in that the image forming arrangement is arranged near the pressure plates ( 38 , 53 ).
26. Apparatus for stereotactic mammography examination for the implementation of a stereotactically guided biopsy, in particular according to one of the preceding claims,
with a stereotactic imaging assembly ( 27 ; 28 ; 36 ),
with a pressure device ( 38 ; 50 ; 53 ) for pinching a breast ( 52 ) of a patient and
with a biopsy needle guide ( 39 ),
characterized,
in that a patient-carrying platform ( 22 ) is provided with a first end and a second end,
that a center of the platform (22) is arranged, the chest (52) receiving Publ voltage (37) freely suspended for one through this opening (37) positioning of the breast (52) is provided, and
in that the opening ( 37 ) forms the platform ( 22 ) in a first support section extending from the first end to the opening ( 37 ) for supporting at least the patient's torso and legs and a second one extending from the second end to the second Opening ( 37 ) extending support portion for storing at least the torso and legs of the patient divided,
such that the patient is free on the first support portion in a first position with a first orientation of the breast ( 52 ) freely suspended by the opening ( 37 ) and on the second support portion in a second position with a second orientation through the opening ( 37 ) hanging chest ( 52 ) is storable.
27. The device according to claim 26, characterized in that a platform ( 22 ) carrying the base ( 23 ) is provided, that a positionable, from the base ( 23 ) projecting support ( 26 ) below the platform ( 22 ) is arranged and that the Imaging assembly ( 27 ; 28 ; 36 ), the printing device ( 38 ; 50 ; 53 ) and the biopsy needle guide ( 39 ) on the support ( 26 ) are attached.
28. The apparatus of claim 26 or 27, characterized in that a concave, flat, the body receiving recess ( 35 ) in the platform ( 22 ) is formed.
29. Device according to one of claims 26 to 28, characterized in that the first and the second support portion of the platform ( 22 ) each have a retractable and retractable footrest ( 43 , 44 ).
30. Device according to one of claims 26 to 29, characterized in that a device for adjusting the height of the platform ( 22 ) is provided.
DE4294430A 1991-11-27 1992-11-25 Stereo=tactic mammography and needle biopsy table Expired - Fee Related DE4294430C2 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US79941291A true 1991-11-27 1991-11-27
US07/957,275 US5289520A (en) 1991-11-27 1992-10-06 Stereotactic mammography imaging system with prone position examination table and CCD camera
PCT/US1992/010327 WO1993011706A1 (en) 1991-11-27 1992-11-25 Stereotactic mammography and needle biopsy table with ccd imaging system
DE4244925A DE4244925C2 (en) 1991-11-27 1992-11-25 CCD imaging device for converting X-rays into an electronic, digital image output

Applications Claiming Priority (1)

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DE4244925A DE4244925C2 (en) 1991-11-27 1992-11-25 CCD imaging device for converting X-rays into an electronic, digital image output

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2633828A1 (en) * 1975-07-31 1977-02-03 Gen Electric mammography
DE3344647A1 (en) * 1983-12-09 1985-06-13 Siemens Ag X-ray diagnosis device with a tiltable patient's support
US4608991A (en) * 1984-09-26 1986-09-02 Southwest Research Institute Method for in-vivo NMR measurements in the human breast to screen for small breast cancer in an otherwise healthy breast
US4727565A (en) * 1983-11-14 1988-02-23 Ericson Bjoern E Method of localization
US4930143A (en) * 1986-09-19 1990-05-29 Bengt Lundgren Method and device for mammographic stereotactic punction of pathological lesions in the female breast
US5018176A (en) * 1989-03-29 1991-05-21 General Electric Cgr S.A. Mammograph equipped with an integrated device for taking stereotaxic photographs and a method of utilization of said mammograph
US5056523A (en) * 1989-11-22 1991-10-15 Board Of Regents, The University Of Texas System Precision breast lesion localizer

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DE2633828A1 (en) * 1975-07-31 1977-02-03 Gen Electric mammography
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DE3344647A1 (en) * 1983-12-09 1985-06-13 Siemens Ag X-ray diagnosis device with a tiltable patient's support
US4608991A (en) * 1984-09-26 1986-09-02 Southwest Research Institute Method for in-vivo NMR measurements in the human breast to screen for small breast cancer in an otherwise healthy breast
US4930143A (en) * 1986-09-19 1990-05-29 Bengt Lundgren Method and device for mammographic stereotactic punction of pathological lesions in the female breast
US5018176A (en) * 1989-03-29 1991-05-21 General Electric Cgr S.A. Mammograph equipped with an integrated device for taking stereotaxic photographs and a method of utilization of said mammograph
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