Abstract:
An X-ray machine for imaging a female breast has a support with an attached continuously rotatable gantry. An X-ray tube with an oppositely located X-ray detector is mounted on the gantry. A locating means for accommodating a breast is disposed coaxially with a rotation axis of the gantry. The gantry is adapted to be moved relative to the locating means by an advancing means. In order to achieve a high throughput of patients, a locating means having an opening for accommodating a breast is provided relative to both sides of the gantry. The X-ray machine may be incorporated between two separating walls which have cut-out portions for the locating means.

Description:
PRIORITY CLAIM 
     This application claims priority to pending German Application No. DE102008042430.7 filed on Sep. 29, 2008. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to an X-ray machine for forming an image of a female breast (mammography). In particular, the invention relates to a machine for performing screening tests efficiently. 
     2. Description of Related Art 
     For performing examinations of female breasts, X-ray machines are known in which a person to be examined is positioned on a patient table. A machine of this kind is disclosed, for example, in U.S. Pat. No. 6,480,565. A shortening of examination time is made possible by X-ray machines such as described in U.S. Pat. No. 5,386,447, in which a person to be examined stands in front of the X-ray machine. From U.S. Patent Application Publication No. 2007/0092059 another X-ray machine is known, in which a radiation emitter and a plate -shaped detector can be moved along a semi-circle around a breast to be examined. Here, exposures could be made at various positions from various angles. With this prior art, it is of disadvantage that, on the one hand, resolution is limited by the plate-shaped detector and that, on the other hand, a relatively long exposure time is required because the radiation emitter and the detector need to be newly positioned between individual exposures. Therefore, an arrangement of this kind is suitable for screening tests only to a limited extent. 
     BRIEF SUMMARY OF THE INVENTION 
     The following description of the objective of the disclosure provided herein and the description of an embodiment of an X-ray machine for imaging a breast is not to be construed in any way as limiting the subject matter of the appended claims. 
     The objective of the disclosure provided herein is to design an X-ray machine which images a female breast in a diagnostically correct manner, and also rapidly, at favourable cost, and at the same time limits radiation exposure to the breast as much as possible. With this, a female patient is to be subjected to as little pain as possible resulting from compression of the breast etc., and instrument resources are to be used optimally. 
     An embodiment of an X-ray machine for imaging a breast of a female patient includes a gantry that is rotatable about an approximately horizontal rotation axis, wherein the X-ray machine is configured to set the gantry into continuous rotational motion for imaging the breast; an X-ray tube mounted on the gantry; an X-ray detector mounted on the gantry substantially opposite the X-ray tube; a locating device for locating the breast in a measurement field of the X-ray machine; and an advancing means for linear displacement of the gantry relative to the locating means and along the direction of the rotation axis of the gantry, with the linear displacement being effected in dependence upon the rotational motion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the following, the invention is described by way of example without limitation of the general inventive concept, on examples of embodiments and with reference to the drawings. 
         FIG. 1  shows a cross-sectional view of an example of an X-ray machine having a gantry disposed between two examination rooms. 
         FIG. 2  shows a partial cross-sectional view of an example of an X-ray machine having a footboard of adjustable height. 
         FIG. 3  shows a partial cross-sectional view of an example of an X-ray machine having a gantry of variable height. 
         FIG. 4  shows a different cross-sectional view of the X-ray machine depicted in  FIG. 3 . 
     
    
    
     While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1  shows an example of an X-ray machine. A gantry  10  which is rotatable about a horizontal rotation axis  12  has an X-ray facility including an X-ray tube  15  and an X-ray detector  14 . To simplify the drawing depicted in  FIG. 1 , X-ray tube  15  and X-ray detector  14  are not shown. However, the devices are shown in the partial cross-sectional view of the exemplary X-ray machine depicted in  FIG. 3 . It is noted that the configuration and placement of such devices described in reference to  FIG. 3  are referenced for the X-ray machine depicted in  FIG. 1  and are not reiterated for the sake of brevity. Referring back to  FIG. 1 , the gantry  10  is displaceable relative to a locating means  40   a  and  40   b  in a direction parallel to the rotation axis  12  with an advancing means  80 . A displacement is effected synchronously with rotation of the gantry  10 . The gantry is disposed between two examination rooms. Walls  25   a  and  25   b  facing the examination rooms are each respectively provided with a breast locating means  40   a  and  40   b . A breast of a first patient  30   a  is accommodated in a locating means  40   a . A breast of a second patient  30   b  is accommodated in a locating means  40   b . It is advantageous for the walls  25   a  and  25   b  to be designed so that they screen-off radiation directed towards the patients. The first patient  30   a  and the second patient  30   b  can be examined with one machine although they are each in a separate examination room. The length of a cylindrical measurement field  18  of the X-ray machine is defined by a maximum travel of the advancing means  80 , which is determined by a space between the separating walls  25   a  and  25   b . As described in more detail below in reference to  FIG. 3 , the width of the cylindrical measurement field  18  may be defined relative to a dimension of the inner bore  17  of the gantry  10 . 
       FIG. 2  shows a partial cross-sectional view of an example of an X-ray machine with a footboard  27  that can be adjusted with a lift drive  26  to position a patient  30  (e.g., patient  30   a  or  30   b  of  FIG. 1 ) in front of the wall  25  (e.g., wall  25   a  or  25   b  of  FIG. 1 ) so that her breast can be accommodated comfortably in the breast locating means  40 . 
       FIG. 3  shows partial cross-sectional view of an example of an X-ray machine in which the substantially disk-shaped gantry is provided with a gantry lift bearing  19 . Although not shown in  FIG. 3  due to the cross-sectional view chosen to show X-ray tube  15  and X-ray detector  14 , it is noted that a breast locating means of the X-ray machine will further be provided with the gantry lift bearing  19 . In this manner, the gantry  10  together with the breast locating means can be adjusted via a gantry lift drive  11 . As noted above, the gantry itself includes the X-ray tube  15  and the X-ray detector  14 . The beam path between the X-ray tube  15  and the X-ray detector  14  is illustrated by an X-ray beam  16 . In this example, the X-ray beam  16  limits the diameter of a cylindrical measurement field  18  to a value that is smaller than that of the inner bore  17  of the gantry. 
       FIG. 4  shows the X-ray machine of  FIG. 3  in a different cross-sectional view, with wall  25  having a cut out wall portion  28 , so that the breast locating means  40  is accessible at any set height. 
     As noted above, an X-ray machine for imaging a female breast comprises a gantry  10  that is rotatable about a rotation axis  12 . Mounted on this gantry is an X-ray facility with an X-ray tube  15  and also an X-ray detector  14 . The X-ray tube  15  emits X-rays along a direction towards the X-ray detector  14 . Locating means  40   a  and  40   b  are disposed at ends of cylindrical measurement field  18 . Locating means  40   a  and  40   b  each serve to accommodate or locate a female breast. For imaging the breasts, the gantry rotates about the rotation axis. At the same time a linear displacement between the gantry  10  and the breasts held in the locating means  40   a  and  40   b  is effected by the advancing means  80 . In this manner, the breasts held in the locating means  40   a  and  40   b  are disposed, at different points in time, in a beam path between the X-ray tube  15  and the X-ray detector  14 . Optionally, the breasts held in the locating means  40   a  and  40   b  can be shifted relative to the gantry  10 . However, it is of particular advantage for the positions of the breasts not to be changed, and for the gantry  10 , therefore, to be shifted relative to the breasts held in the locating means  40   a  and  40   b . The direction of movement is preferably parallel to the rotation axis  12  of the gantry. The movement can be effected optionally to be continuous at constant speed, or proportional to the rotation of the gantry. Alternatively, the movement also can be effected stepwise, so that, for example, a displacement amounting to a width of the detector is effected following each revolution of the gantry. 
     The measurement field of the X-ray machine can be defined by the inner bore  17  of the gantry and by the range in which the gantry  10  can be displaced by the advancing means  80 . This measurement field is of a cylindrical shape. The range of a breast to be examined must project into the measurement field. 
     Owing to the design of the X-ray machines described herein, it is not necessary to use a large-area detector which can image an entire breast. Rather than this, a smaller X-ray detector  14  which has a substantially shorter width along a direction parallel to the rotation axis  12  than the length of a breast in the locating means  40   a  or  40   b  is adequate. Thus, an X-ray detector  14  having a substantially larger resolution can be used. Three-dimensional data of high diagnostic information content can be generated. A recording technique which is advantageous is the spiral CT technique. Here, the measurement field is scanned with a spiral movement, whereby complete imaging can be performed within a few seconds. With this, it is also possible to reduce substantially the time needed per person to be treated. 
     Locating means  40   a  and  40   b  each have at least one opening for receiving a female breast. It is advantageous to perform fastening or stabilizing of the breast with the aid of a cup or bell-shaped vessel in which a breast can be held by sub-pressure. However, other methods of fastening using rings, cords, mechanical or adhesive devices are also possible. In either case, the locating means is designed so that a principal axis of a breast, formed by a plane perpendicular to the chest wall and the nipple, extends horizontally along the rotation axis of the gantry. As discussed in reference to  FIG. 1 , the X-ray machines described herein may, in some embodiments, include two locating means respectively disposed relative to each side of the gantry. With this arrangement, a breast positioned in a locating means can be already imaged whilst another breast is being positioned in a second locating means. With this, an almost continuous operation of the X-ray facility on the gantry is possible. Thus, efficient screening tests can be performed. The locating means are preferably exchangeable. Thus, each locating means can be adapted to the size of a breast of a person to be examined, and/or exchanged following an examination. 
     In some embodiments, an X-ray machine may be disposed behind a single thin wall which adjoins an examination room. In alternative embodiments, however, one examination room can be located on each of the two sides of an X-ray machine, the one examination room being closed off from the X-ray machine by one more thin walls. In yet other embodiments, as described in reference to  FIG. 1 , an X-ray machine may be disposed between distinct walls which adjoin different examination rooms. In such a scenario, the gantry can now be moved with the advancing means between one part of the locating means assigned to a first examination room and a second part of the locating means assigned to a second examination room. In any of such cases, only the locating means of the X-ray machine is/are visible from the examination room/s. 
     The X-ray machines described herein may be fitted with a pedestal for setting-up the machine on a floor, or with a wall fastening for mounting the machine on a wall. 
     In addition or alternatively, the gantry  10  is of adjustable height, so that it can be adapted to various body sizes of persons to be examined. In order to make possible a simple adjustment of height, a compensation of weight by springs or counterbalancing weights may be provided. In some embodiments, an adjustment of height may be effected with a lifting device, such as with a motor and more specifically with an electric motor. 
     In some cases, it may be advantageous to provide a footboard  27  or step of adjustable height, on which a person to be examined can stand. The height of this footboard can be adjustable with a lifting device, such as a motor, and more specifically with an electric motor. 
     It is special advantage for a breast to be fastened in the locating means using sub-pressure or vacuum. An undesired compression of a breast is thereby avoided. 
     In some embodiments, the X-ray machine may be a spiral CT instrument. In some embodiments, the X-ray machine may be a sequential CT instrument. In such an instrument, the gantry makes circular scans and is laterally moved by the gantry lift drive after completion of a circle. 
     It will be appreciated to those skilled in the art having the benefit of this disclosure that this invention is believed to provide X-ray machines for imaging a breast. Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims.