DE102011080682A1 - Method for controlling digital stereotactic biopsy using mammography device, involves capturing overview image of object area for biopsy, where two stereotactic images are captured, which comprises two images from different directions - Google Patents

Abstract

The method involves capturing an overview image of an object area for biopsy. Two stereotactic images are captured, which comprises two images from different directions. The captured stereotactic images are represented with the overview image for marking a target object. The marked data is read, which is placed in two images by a computer-aided input unit. The computed three-dimensional position data of the target object is automatically transformed in the overview image for creating a modified overview image. Independent claims are included for the following: (1) a positioning device with a control module for a needle holder of a biopsy device; and (2) a computer program product loaded into an internal memory of a digital computer.

Description

The invention relates to a method, a positioning device, a control module, a computer program product and a biopsy device for controlling a digital stereotactic biopsy using a mammography device.

In a medical examination of the female breast, it is often necessary to remove tissue. This is achieved by means of a biopsy needle as part of a biopsy, which must be performed accurately and correctly to the respective position of the tissue to be examined using an imaging system, for example using a radiation unit or mammography device or an ultrasound device. It is of particular importance to precisely position the biopsy needle before the puncture in the tissue to be examined on a target point or on a target object. In today's systems, the calculation of the target point is based on the images acquired by the imaging system.

In the usual procedure in the prior art, the female breast is compressed after storage of the patient by a compression system. An x-ray device of the mammography device is then guided to a first position in order to capture a scout image (also referred to as an overview image in the following) from the breast. On the basis of this first image, it can be determined whether the object area to be examined is as central as possible and of sufficient quality visible on the scout image. If this is not the case, the breast can be repositioned to capture a new Scout Image image. A usual procedure of a stereotactic mammography further provides for capturing at least one stereotactic image pair. Usually, two images from different angular positions (projections) are acquired here. For this purpose, an X-ray device of the mammography device can be moved to a first angular position (for example -15 ° or -25 °) for recording a first image of the stereotactic image pair, in order then to be converted into a second angular position for recording the second image (for example + 15 ° or + 25 °). The two stereotactic images are then displayed on a workstation and viewed by the doctor. After the image acquisition by the mammography device and its display on a computer, it is provided that the doctor marks the target object (ie the tissue to be biopsied) in both stereo images shown. The scanned marker data is then used to calculate the spatial position of the target object and then forward it to a needle holder positioning device of the biopsy device for positioning the needle holder. The needle is then automatically positioned based on the calculated position based on the marker data and for performing the biopsy prepared.

Practice shows that problems may occur with the prior art method described above. On the one hand there is the problem that the target object is only visible in one of the two projection shots, because it is obscured, for example, in the other projection by an obstacle (for example denser tissue). In the previous methods in the prior art, a biopsy based on the captured image pair is not possible in this case since the spatial position determination from the two image projections is not possible. On the other hand, there is the problem of marking tissue changes (for example benign or malignant microcalcifications or other histologically significant or otherwise significant atypia of the tissue). This is particularly difficult if many tissue changes (for example, many calcifications) can be seen in the images shown. For the spatial position determination, it is necessary to mark the position in two image recordings in order to be able to calculate a three-dimensional position data set for controlling the biopsy needle. For this it is necessary that the tissue changes visible in the two stereotactic images must be assigned to each other. In other words, it is important that in the two images of the stereotactic image pair also the same tissue structure is marked. Practice shows that, in particular in tissue structures that comprise several different target objects, errors often arise in that different target objects are marked in the two projection images. This will calculate an incorrect target position and, as a result, will result in tissue being removed at a wrong target position.

The starting point of the present invention was therefore the solution of the two problem areas mentioned above, namely a faulty or non-executable position determination, since the target object is not visible in all images and errors due to an incorrect assignment of tissue structures in the two image projections of the stereotactic image pair.

Disadvantageously, in the previous methods the breast had to be repositioned each time (which implies a decompression of the breast, an altered positioning of the patient and an additional X-ray exposure) if the target tissue to be examined or biopsied was not visible on both stereo projections.

Furthermore, an incorrect assignment of the marked tissue structures in the two stereo projections was either not recognized, resulting in the result that wrong tissue was removed or the error is detected only in a control recording, so also a re-biopsy must be performed.

From a medical point of view (radiation exposure for the patient) and also from an efficiency point of view (for example duration and costs of the biopsy procedure) these problems and the associated disadvantages are not sustainable.

The present invention has therefore set itself the task of proposing an approach by which these problems can be solved and the disadvantages can be avoided. With the solution according to the invention, the duration of the biopsy procedure is to be shortened. Furthermore, the radiation exposure for the patient is lowered and the quality of the medical examination is improved. In particular, an improvement and further control options for determining the position should be provided.

This object is solved by the accompanying independent claims, in particular by a method, a positioning device, a control module, a computer program product and a biopsy device.

In the following the invention will be described with reference to the method according to the solution. Definitions of terms mentioned here, alternative embodiments, advantages or further developments can likewise be applied to the other forms of claim, and thus also to the representational forms (positioning device, control module, computer program product and biopsy device). In this case, the corresponding functional features are provided by corresponding modules, which can sometimes be provided as a microchip component or as a hardware element, and are intended to carry out the respective functionality of the method step. Thus, the modules describe the respective functionality of a component of a hardware device (for example, a processor or coprocessor). The same applies, of course, vice versa, so that the advantages or features that are described in connection with the subject solution can also be applied to the process as well. On the basis of Church's thesis, it will be apparent to one of ordinary skill in the art that a hardware implementation that can be objectively claimed may be equivalently implemented as a software solution.

• – Erfassen eines Scout Images (im Folgenden auch als Übersichtbild bezeichnet), in dem zumindest ein zu biopsierender Objektbereich enthalten ist. Bei dem zu biopsierenden Objektbereich kann es sich beispielsweise um Kalzifikationen oder um sonstige Gewebeveränderungen handeln.
• – Erfassen von zumindest einem stereotaktischen Bildpaar, umfassend ein erstes und ein zweites Bild, die jeweils aus unterschiedlichen Projektionen (bzw. Richtungen oder Winkeln) erfasst wurden.
• – Darstellen der erfassten Bilder, insbesondere des stereotaktischen Bildpaares und des Übersichtsbildes, zum Zwecke der Markierung zumindest eines Zielobjektes. Das Zielobjekt kennzeichnet die Gewebestruktur, die biopsiert werden soll.
• – Einlesen von Markierungsdaten, die in zwei Bildern (aus jeweils unterschiedlichen Projektionen) durch ein computer-gestütztes Eingabemittel gesetzt werden, um dreidimensionale Positionsdaten des Zielobjektes zu berechnen. Üblicherweise markiert ein Arzt eine bestimmte (Ziel-)Position (target) in beiden Stereobildern. Die 3D-Positionsdaten werden automatisch aus den eingelesenen Markierungsdaten berechnet und in allen dargestellten Bildern, insbesondere auch in dem Übersichtsbild dargestellt, nämlich durch:
• – Automatisches Transformieren der berechneten dreidimensionalen Positionsdaten des Zielobjektes in das Übersichtsbild zum Erstellen eines modifizierten Übersichtsbildes, in dem die Positionsdaten eingefügt sind.
• – Automatisches Darstellen des modifizierten Übersichtsbildes mit den transformierten Positionsdaten und der beiden stereotaktischen Bilder mit gesetzten Markierungsdaten auf einer grafischen Benutzeroberfläche zur Positionskontrolle. Dabei werden vorzugsweise alle drei Bilder (stereotaktisches Bildpaar und Übersichtsbild) in einer gemeinsamen Bildschirmdarstellung parallel und gleichzeitig dargestellt.
• – Bereitstellen einer Korrektur- bzw. Benutzerinteraktionsmöglichkeit zur Korrektur, Verfeinerung oder Änderung der (bisher eingefügten) Markierungsdaten. Sobald eine Änderung der ursprünglich gesetzten Markierungen erfasst wird, wird automatisch ein erneutes Darstellen der Bilder mit den korrigierten bzw. geänderten Markierungsdaten und entsprechend automatisch geänderten Positionsdaten ausgelöst und veranlasst (dynamischer Darstellungs- und Änderungsmodus). Diese Korrekturmöglichkeit kann optional auch mehrfach bzw. iterativ angewendet werden, bis ein zulässiges Positionsergebnis erzielt werden kann.
• – Positionierung eines Biopsienadelhalters mit den (als zulässig bestätigten) Positionsdaten.

One aspect of the present invention relates to a method for controlling and in particular positioning a biopsy needle as part of a digital stereotactic biopsy using a mammography device, wherein an object (in particular the female breast of a patient) for detecting (eg mammographic) images in a Compression system is compressed. The method comprises the following method steps:

• - Capture of a scout image (hereinafter also referred to as overview image) in which at least one object area to be biopsied is included. The object area to be biopsied may be, for example, calcifications or other tissue changes.
• - Detecting at least one stereotactic image pair, comprising a first and a second image, which were each detected from different projections (or directions or angles).
• - Representing the captured images, in particular of the stereotactic image pair and the overview image, for the purpose of marking at least one target object. The target object identifies the tissue structure to be biopsied.
• - Reading marker data, which are set in two images (from different projections) by a computer-based input means to calculate three-dimensional position data of the target object. Usually, a doctor marks a specific (target) position (target) in both stereo images. The 3D position data are automatically calculated from the scanned marking data and displayed in all the images shown, in particular also in the overview image, namely by:
• - Automatically transform the calculated three-dimensional position data of the target object into the overview image to create a modified overview image in which the position data is inserted.
• - Automatic presentation of the modified overview image with the transformed position data and the two stereotactic images with set marking data on a graphical user interface for position control. In this case, preferably all three images (stereotactic image pair and overview image) are displayed in a common screen display in parallel and simultaneously.
• - Providing a correction or user interaction option for correction, refinement or modification of the (previously inserted) marking data. As soon as a change of the originally set markings is detected, a re-presentation of the images with the corrected or changed marking data and correspondingly automatically changed position data is automatically triggered and initiated (dynamic presentation and modification mode). This correction option can be optional be applied repeatedly or iteratively until a permissible position result can be achieved.
• - Positioning of a biopsy needle holder with the (confirmed permissible) position data.

The terms used in the context of this patent application are explained in more detail below.

The term "control" of the biopsy refers in particular to a position control of the biopsy needle or the controllable biopsy needle holder of the biopsy device. According to a preferred embodiment, the control is fully automatic; that is, there are no user interactions for positioning the biopsy needle. This can advantageously be avoided errors due to manual incorrect entries. Another aspect of the control relates to the timing. Due to monitoring measures, checking measures (for example on consistency of the marked positions) and on the basis of verifications as to whether the position of the marked target object is even within the biopsable range, the biopsy is also timed. Only after all verification procedures have been successfully completed and no error is indicated, a verification signal is issued, on the basis of which the biopsy can be initiated. If the verification signal can not yet be provided, the biopsy can not be performed either.

In the usual embodiment, the "subject" of the patient is the female breast, which contains one or more object areas that are of diagnostic or other medical interest. The object area may be, for example, tissue changes of all kinds, including microcalcifications, tumor tissue or other tissue structures. The tissue structures include benign and malignant structures. A "target object" is a specific position or area of tissue within the female breast that is to be biopsied. This may be, for example, a specific microcalcification of several microcalcification areas. Of course, the proposal of this patent application can be applied not only for a biopsy of the female breast, but also to other objects of a patient from which tissue is to be removed by means of a biopsy. In this case, the images are not captured by a mammography device, but by other imaging modalities, such as a computed tomography scanner, a conventional C-arm X-ray machine, ultrasound machines, or other imaging techniques.

The overview picture is characterized by the fact that it is acquired with certain settings. In particular, it is envisaged that either the entire breast or a region of interest of the breast is completely displayed (for example ROI - Region of Interest). The overview image is usually acquired in a 0 ° position. Alternatively, other angle settings are possible, but the angular range of the overview image deviates from the angular range of the two stereo images. In a preferred embodiment, further settings are preconfigured here, in particular with regard to resolution, possible dispensing of contrast agents, etc.

Usually, two stereotactic images or image recordings are acquired. These are x-rays of the compressed breast at different angles (e.g., ± 15 ° or ± 25 °). The overview image is acquired in a deviating angular position. Of course, here are also other angular ranges for the acquisition of images within the scope of the invention. In a preferred embodiment, only a stereotactic image pair is detected and used for marking and position calculation. Alternatively, however, it is also possible to use several stereotactic image recordings and to use them for the calculation. Another alternative is that not a pair of images is used, but that three or more images are captured in different projections and used to calculate the position. It is also possible to set the markers in a stereotactic image and in the overview image and to use the respective other stereotactic image for the consistency check of the calculated 3D position.

From the captured images, at least two are selected and designated for marking. In other words, at least two of the captured images are used for marking. This is done by the physician manually marking a particular position in the image display via the computer-aided input means (for example the mouse or other user interfaces). This generates two tag records. These marking data records are read in and from this a three-dimensional position is calculated, which records as position data record in digital form. In an advantageous development, it is provided that the physician inserts marker data not only in the (two) stereo images, but additionally - if necessary, several - used images to insert marker data or set, which then all or partially used to calculate the position data become. This may be useful, for example, if several, different calcifications or other tissue changes are present.

In the context of this invention, a distinction is made between the terms "image" and "modified image". The term "image" refers to the acquired image acquisition. This is essentially in original form. In contrast, a modified image is characterized by the fact that position or marking data has been inserted or superimposed. Either the marking data are manually set by the doctor directly in the image or the position data were automatically calculated by means of the method according to the invention and inserted into the image and localized to a correlated calculated position. In particular, the overview image is available both in original form as well as in modified form. To prepare a respective modified image several preparation steps are necessary. In particular, it is necessary to perform calculations such that the manually inserted marker data is displayed as position data at the respective calculated position in the image. This may preferably be in the form of an overlay graphic or otherwise superimposed on the original image.

Thus, "transforming" the marker data from one image to other images involves correlatively transmitting the respective 3D coordinates. This requires several processing and calculation steps. On the one hand, the three-dimensional position is calculated from the inserted marking data and then transformed into the coordinate system by mapping the image so that a clear association between marking data and position data becomes possible.

The overview image is preferably recorded vertically from above (relative to a body longitudinal axis of the patient) as a so-called cc image (craniocaudal image). According to the prior art, the overview image is only used to determine whether the area to be biopsied is also in the image area. If this is not the case, the patient must be stored again to take a new overview. According to the invention, the overview image is additionally used for determining the position by projecting or transferring marking data that has been recorded in other images (preferably in the stereo projections) onto the overview image. Thus, the quality can be significantly improved because not only two but three shots from different projections can be used for position determination. In addition, a verification of the marking data and thus the biopsy position is possible.

According to one essential aspect of the invention, it is provided that the marking data which has been introduced in a stereo projection and in a further image or in both stereo projections are additionally backprojected into the overview image by the course of a computer-implemented calculation rule and displayed there.

• – Vor der Vergrößerung der Stereoprojektionen werden die Markierungsdaten in beiden Stereoprojektionen zunächst grob an die Zielposition gesetzt.
• – Anschließend werden mit Hilfe der Zoom-from-Target-Funktionalität beide Stereoprojektionen automatisch so gezoomt, dass der markierte Bereich im Zentrum des dargestellten Bildausschnitts vergrößert sichtbar ist.
• – Darüber hinaus wird auch der Zielbereich im Übersichtsbild automatisch entsprechend mit vergrößert und ist somit an die Darstellung der Stereoprojektionen angepasst.
• – Nachdem alle drei Bilder mit entsprechend korreliertem Zoomfaktor und Panbereich justiert dargestellt werden, kann die Target-Position optimal auf das Zielobjekt justiert werden.

The usual procedure requires that a doctor or other medical personnel mark a target position manually in at least two of the captured images (for example with the mouse). In order to be able to carry out this marking task with sufficient precision, the respective image is usually enlarged in advance so that the area of interest is displayed enlarged. It may also be necessary to move the section of the picture so that the area of interest at the correct magnification also appears in the center of the displayed picture. Typically, therefore, the user will determine a zoom factor that describes the magnification or reduction of the image and determine a pan range that indicates which portion of the image data is to be displayed. In the prior art, it was provided in the above-mentioned method that the respective operations (determining the zoom factor and determining the pan range) had to be carried out individually for each image. This resulted in errors if different zoom factors or different pan areas were selected in the images displayed. A further disadvantage of the prior art procedure was that the zoom function and the shift function (PAN function) had to be executed not only separately for each image, but also in separate work steps. This resulted in increased delivery times and decreased overall biopsy efficiency. To overcome these disadvantages, the present application provides a so-called zoom-from-target functionality. With this zoom-from-target functionality, a quality improvement and shortening of the biopsy procedure can be achieved. In particular, the number of necessary work steps can be reduced. Preferably, the following workflow can be used:

• - Before enlarging the stereo projections, the marker data in both stereo projections are first roughly set to the target position.
• - Then, using the zoom-from-target functionality, both stereo projections are automatically zoomed so that the highlighted area in the center of the displayed image section is enlarged.
• - In addition, the target area in the overview image is automatically enlarged accordingly and is thus adapted to the representation of the stereo projections.
• - After all three images are displayed adjusted with correspondingly correlated zoom factor and pan range, the target position can be optimally adjusted to the target object.

A significant advantage is that the process as a whole can be performed more efficiently by performing fewer operator actions (mouse activity). In addition, the target area or the target object is automatically centered. Furthermore, it can be ensured that the same magnification factors (zoom factors) and pan ranges are always used in unison for all displayed images. This can be avoided errors that have arisen in the previous approach by different magnification factors or by the selection of different image areas for the representation. A further advantage is to be seen in the increase in quality, since the automatic correlation of zoom factor and pan range makes a clearer representation and improved control of the target position possible.

In other words, the present invention provides the adapted representation of the stereotactic images and the overview image. In the adjusted display, the zoom factor and the pan range of all displayed images are standardized. If more than these three images are to be displayed (for example with an additional verification of the marking data in a further projection), then the zoom-from-target functionality can be applied to all or to selected ones of the images to be displayed.

In a preferred development, it is provided that the zoom-from-target functionality is basically applied to all images to be displayed. Optionally, however, it can be provided that certain images are displayed in the original version. These may, for example, be reference images from previous examinations or other images that should not be displayed with adapted or changed zoom factor and pan range.

In addition, the zoom-from-target functionality can be optionally switched on and off. Furthermore, certain zoom factors and pan areas can be preconfigured, which prove to be useful in a large number of cases, so that automatically certain presets for displaying the adjusted stereo projections and the overview image are selected, which of course can be saved and / or overwritten at any time.

According to an advantageous development of the invention, the transformation of the marking data comprises a transfer of the respective position or the calculated position data into non-manually marked images. Preferably, the position data are transferred to the overview image and displayed there. The transformation comprises a position calculation, a back projection for inserting the position data into the overview image and a correlated insertion of the position data into further images, comprising all or selected unmarked images. Transforming the position data thus refers to a correlated insertion thereof to a position in the respective unmarked image that corresponds to the position of the marked image (in which the marking data was manually set). It is usually intended that marker data be inserted in both recordings of the stereo projections. For example, the user marks a first position in the left image and a second position in the right image (the stereotactic images). From this, we calculate your 3D position data set, which is then displayed on at least one other unmarked image at the respective position. By representing the position on a third image (captured at a different angle), the two marked positions can be easily and efficiently checked for consistency.

An important aspect of the invention is also to be seen in that a (multi-repeatable) correction and refinement of the markers is made possible by a user interaction option is provided, with which the user can correct, change or refine his previous markers. For this purpose, the zoom-from-target functionality described above is advantageous. If the marking is modified in one picture, in particular in one of the three pictures, then (if necessary) the two other markings are automatically adjusted so that all three markings relate to the identical 3D position. The representation of the (preferably three) images thus always takes place on-the-fly with the currently entered marking data. This correction function can be executed as often as required until a permissible position result can be achieved.

Furthermore, it is detected by a check calculation whether the positions indexed by the marker data are even in the area to be biopsied. If this is not the case, a warning signal is also output automatically or the user is requested to correct the marking data (if necessary under a note). Due to the warning signal, the user can then repeatedly make the insertion of corrected marking data.

An essential advantage of the solution according to the invention is the fact that an association between the respective object areas is possible, which are made visible in the different projections and images. One aspect of the invention relates to mapping functionality based on a position comparison between more than 2 images and ensuring that the target object marked in the first image matches the target object marked in the second image where, if coincidence, a match signal can be issued. This is achieved by backprojecting the position calculated from the two marking data sets into the overview picture and displaying it there. If the display of the re-transformed position in the third image is not within an allowable range, it is assumed that the marked target objects do not match. The user can be asked to correct his input.

According to one aspect of the invention, it is automatically checked whether the target object has not been falsely marked incorrectly by misregistration (eg, not obscured by other tissue structures). If an error is detected, a warning signal is automatically output and / or the user can re-mark. The repeated execution of the biopsy with a corrected position data set, as was sometimes necessary in the case of an error in the prior art, can thus be avoided.

If one of the two stereotactic images is not of sufficient quality, the user can be offered by providing a replacement routine to perform the position calculation on the basis of other label data, for example the labels inserted in the stereo image with sufficient quality and in the overview image. This can replace the overview image of one of the two stereotactic projection images, which is in poor quality. Of course, other images can be used.

An important aspect of the invention is thus to be seen in that the overview image is not only used - as in the prior art - to control the position calculation and the image quality, but also for calculating the position of the target object for biopsy. Thus, the overview image is additionally used as an aid in determining the target position (so-called targeting). It is essential that parallel to the two stereo projections in addition, the overview image is displayed separately but simultaneously, so that the target object from at least three projection directions is visible. If the target object (target) is marked (position-determined) in both stereo projections, then according to the invention this marker data (target) is automatically projected onto the overview image.

Thus, according to the invention, a position determination of the target object is present in three different projections. This can be used to automatically initiate and execute monitoring actions that indicate that incorrect positions have been marked. In addition, an association of marking data and / or object areas, which are displayed in different images, is possible.

Exemplary embodiments with further alternatives and advantages of the invention will be explained in more detail below with reference to the figures. Showing:

1 a schematic representation of a compressed breast for mammographic capture of images in a stereotactic biopsy;

2 a schematic representation of a positioning device for a needle holder;

3 a schematic representation of components of a biopsy device;

4 3 is a flowchart of a process according to a preferred embodiment of a method according to the invention,

5 a schematic overview of components or devices and the data exchange according to an advantageous embodiment of the invention and

6 a schematic representation of a mammography device according to an embodiment of the invention.

1 shows a schematic overview representation of a female breast B, which is fixed in a compression system K, comprising two compression plates K ₁ , K ₂ stored and compressed to perform a stereotactic digital biopsy using a mammography device 40 , In 1 is the mammography device 40 only partially and in principle shown with an X-ray emitter 401 and an X-ray detector 402 , For reasons of clarity in the figures, the other components of the mammography device 40 or other imaging modalities not shown. The pictures are taken in pairs from different directions. This should be in 1 be indicated by the dotted curved line with the beam angle range. Basically, the detector remains 402 stationary and the X-ray emitter (s) 401 turns / revolve around a rotation isocenter R (cf. 6 ).

The mammography device 40 serves to capture an overview image SI, in which at least one object area to be biopsied is included. After acquiring the overview image, it can be provided according to an advantageous embodiment of the invention that the overview image SI on a user interface 30 is pictured. The representation of the overview image SI can be used to check whether the object area to be biopsied is also displayed in the center of the overview image SI. If this is not the case, the patient must be stored again so that the breast B can be fixed and compressed in another position. However, according to the invention, the representation of the overview image SI also has a checking function.

The following will be related to 5 the concept of the present invention explained in more detail. In the lower part of the 5 is shown a patient whose breast B is to be examined by means of a biopsy. As related to above 1 described, the breast B is compressed between compression plates K ₁ , K ₂ fixed in order to produce a stereotactic image recording can. This is what a mammography device stands for 40 to disposal. In alternative embodiments, there may be other imaging modalities, for example, an ultrasound machine 41 and other imaging modalities 42 be used. The mammography device 40 and / or the other imaging modalities 41 . 42 generate image data BD which is sent to a calculation module and / or to a control module 50 to get redirected. The calculation module is designed as a computer module or computer-based entity and includes a user interface 30 for interacting with the user, a control module 50 and a positioning device 20 , All of the above instances are in communication with each other over a network (for example, TCP-IP based networks or a CAN bus). In the upper section of 5 is shown schematically that inputs are made via the user interface. This is done by the user, in particular a doctor who operates the system (in 5 Not shown). It interacts with the system via the user interface 30 , As in 3 indicated schematically, there is the user interface 30 from a screen surface that serves to visually render image data and computed, modified images. In addition, the doctor can mark data MD or corrected marking data through the user interface 30 enter, which will then be used for further calculation.

In 2 is the positioning device 20 illustrated in more detail in a schematic way. It includes a position module 22 and a read-in module 24 , The read-in module is used for reading in marking data MD. The marking data MD in turn serve to calculate a target position for the positioning device 20 , The positioning device 20 also includes the position module 22 for positioning a needle holder 10 with a biopsy needle N of a biopsy device 60 serves. The positioning of the needle holder 10 is done by a three-dimensional data set (position data PD), which is calculated from the marking data MD. As in 2 indicated schematically, the thus calculated position data PD directly to the needle holder 10 forwarded, which is preferably driven by a small servo motor and performs a positioning of the needle N. In this embodiment, the needle holder 10 designed as a motorized device that is operated fully automatically. The position data PD serve to position the needle holder 10 with the needle N. Alternatively, it is possible to use the needle holder 10 form not motorized, but a manual positioning of the needle holder 10 provided. Then the needle holder becomes 10 due to the calculated positioning data PD manually positioned with respect to the target object to be biopsied.

The following is with reference to 3 an advantageous embodiment of a biopsy device 60 explained in more detail. It includes a control module 50 , the positioning device 20 and a user interface 30 , The aforementioned modules also interact with the needle holder 10 , which is intended for positioning of the biopsy needle N.

The following is with reference to 4 a flow according to a preferred embodiment of the invention explained.

In a preparatory step S1, preparatory measures are carried out. These include patient positioning, breast B positioning within the compression system K, and compression of the breast B. Alternate embodiments contemplate injection of a contrast agent or other medical procedures.

In a step S2, an overview image SI is detected in which at least one object region of the breast B to be biopsied is shown. This can be saved.

In step S3, at least two stereotactic images are captured, which are optionally also stored, and thus also available for later access. The stereotactic image pair comprises a first and a second image consisting of be detected in different directions. While the overview image SI usually represents a 0 ° view for the location of the breast B, the images of the stereotactic image pair images relate to projection images at different angles, for example a ± 15 ° angle region. However, the angle range for the embodiment of the present invention is not limited to the number of degrees of 15 °, but here can be other angle sizes (also a range of ± 25 ° is conceivable).

In step S4, the captured stereotactic images, together with the overview image SI, are used for the purpose of marking at least one target object on the user interface 30 shown. The doctor can sift through the images displayed and insert marker data MD into the images. This is preferably done manually. However, it can also be supported by offering it a marking target area calculated as permissible (a marking corridor, so to speak) for marking. For example, the physician may place a marker in the first image (for example, by clicking on a specific position on the monitor with the mouse). Thereupon, it is automatically called a marking area in the second image, within which he can make another mark in the second image. Typically, the physician marks a target (ie, a target area for the biopsy needle N) in the first and second images of the stereotactic images.

In the subsequent step S5, the marking data MD (manually or semi-automatically) entered is read in and processed. Three-dimensional position data PD is calculated from the marking data MD.

In step S6, the calculated position data PD is automatically transformed. As already mentioned above, the position data PD are inserted in the overview image SI at the respective position. In this case, the 3D position of the position data PD corresponds to the marking data MD both in the first image and in the second image of the stereotactic image pair. All pictures are shown in parallel. The stereo image pair with the markings and the overview image with the transformed and calculated position data PD are preferably displayed. This is advantageously done on a common user interface. Preferably, therefore, the two set marks can be checked for consistency. This includes checking whether the markers are still within the biopsable area of the object. Only if these checks have produced a positive result (which can be made by changing the markings - described below) will the procedure be continued.

Now the user can still make changes, fine adjustments or corrections to the markers, which are then immediately retraced in the displayed representation (so to speak online), so that any change can be immediately visually reproduced (and thus checked). After these user inputs have been captured, the images are redrawn again. The first image is displayed with the entered marker data MD, the second image is also displayed with the entered marker data MD, and the overview image SI is also displayed with correlated and transformed marker data MD or with position data PD. It is provided that a three-dimensional position is calculated from the entered marking data MD. This position is backprojected and inserted back into the overview screen SI using a calculation rule. The following definitions are made:
System constants:
L _ARM = length of rotation arm (distance of radiation emission point from isocenter of rotation R)
D _ISOC = distance of the isocenter R from the detector 402

specifications:

•  - In the 0 degree position of the tube (α = 0), the radiation emission point is centered in the right / left direction above the detector. In forward-return direction, the radiation emission point is flush with the detector edge on the patient side. This point of the detector is called Beam Center.
• - For the calculations, the BeamCenter coordinate system is used, i. the origin of the coordinate system lies in the BeamCenter point at the detector level.

The angle α is subtended between a detector perpendicular and a line between the emission point and the rotational isocenter R. He is in 6 shown.

Input values for the calculation are:
X _S1 : Marked X position in the first stereo image
Y _S1 : Marked Y position in the first stereo image
α _S1 : Angle of the first stereo image - relative to the detector vertical
X _S2 : marked X position in the second stereo image
Y _S2 : Marked Y position in the second stereo image
α _S1 : Angle of the first stereo image - relative to the detector vertical

Initial values of the calculation:

• X _T = X position of the target in the BeamCenter coordinate system
• Y _T = Y position of the target in the BeamCenter coordinate system
• Z _T = Z position of the target in the BeamCenter coordinate system

Projection of the 3D target position Position on the overview image SI:

Input values for the calculation:

• Winkel _Ü Angle of the overview image - relative to the detector vertical (normally 0 degrees)
• X _T = X position of the target in the BeamCenter coordinate system
• Y _T = Y position of the target in the BeamCenter coordinate system
• Z _T = Z position of the target in the BeamCenter coordinate system

Initial values of the calculation:

• X _Ü : Marked X position in the overview screen SI
• Y _Ü : Marked Y position in the overview screen SI

By executing this transformation step, the overview image becomes a modified image. In this case, the modified images respectively include the marking data MD and the calculated position data. The marker data MD in the modified images identify the target position (target) for performing the biopsy.

In step S7, the modified images are displayed. In particular, the modified overview image SI (with the position data) and the two stereotactic images with the set and transformed marking data MD are displayed. If inconsistencies are found or if the representation on the 3 different images from 3 different directions necessitates changes or corrections of the calculated position data, the method can be continued again at step 4 by inserting other marking data and using it for the further calculation. This is in 4 indicated by the dashed line of S7 to step S4. If necessary, it is also possible to return to step S3, if retakes of stereo projections are necessary.

In the last step S8, the position data for determining the position of the target object are used for the biopsy, wherein from the marker data MD a three-dimensional data set as a position data set to the positioning device 20 for positioning the biopsy needle holder 10 is passed on.

An essential aspect of the present invention thus relates to the determination of the target position (target or targeting) using at least three images (in different projections with known projection geometry), in particular using the overview image SI and using the stereotactic images with the marking data MD. Thus, images of the object to be biopsied are present in three different angles (overview image and stereo image1 and stereo image2).

• – Die Darstellung des stereotaktischen Bildpaares
• – die Darstellung des Übersichtsbildes SI und
• – optional eine weitere Bilddarstellung, in der eine Grobdarstellung mit entsprechender Winkelangabe, zum Beispiel CC-Ansicht (cranio-caudal), MLO-Ansicht (mediolateral oblique), LO-Ansicht (lateromedial) etc. dargestellt sind, und
• – optional: zumindest ein Fenster zur Darstellung und Erfassung von weiteren Benutzersignalen, zum Beispiel von Bestätigungssignalen oder zur Ausgabe von Warnsignalen etc. oder weiteren Informationen (Zeit etc.) und Metadaten.

Thus, since not only the stereotactic image recordings are used to calculate the position for the biopsy, as known in the prior art, the user interface is 30 also different. This is schematically in 3 displayed. The user interface preferably comprises the following elements:

• - The representation of the stereotactic image pair
• - The representation of the overview image SI and
• Optionally, another image representation, in which a rough representation with corresponding angle indication, for example, CC view (cranio-caudal), MLO view (mediolateral oblique), LO view (lateromedial), etc. are shown, and
• Optionally, at least one window for displaying and recording further user signals, for example acknowledgment signals or for issuing warning signals, etc., or other information (time, etc.) and metadata.

An essential aspect of the invention is thus to be seen in the fact that all images used for calculating and checking the position data PD are displayed together on a screen surface (for example in a common window). This is preferably done simultaneously. Thus, the user can advantageously immediately and immediately get an overview and a control over the position determination.

Another important aspect of the invention is the provision of a program routine for improved display and entry of marker data MD. This program routine implements a so-called zoom-from-target functionality, in which an automatic transmission of the specific zoom factor and the specific pan range from the images in which the marker data MD are inserted manually to the other images (for example, via the overview image SI) is provided.

This will be described below by way of example with reference to the in 3 displayed screen surface 30 be explained in more detail. In the upper left area of the screen surface is the first projection image with the inserted marking data MD. These are in 3 shown schematically as a cross. In the upper right area of the screen surface is the second image, which was taken in a different angle range. After inserting the marking data MD into the left picture I1, a marking area (or an area for permissible markings or an input corridor) is automatically displayed in the other picture of the stereotactic picture pair (here picture 2: I2). In 2 this is indicated schematically by the representation of a line. The marking data MD may therefore only be inserted in this line in the second picture I2. After the user has also entered this marking data MD in the second image I2, a calculation of the calculation module takes place. This serves to determine or calculate position data PD from the marking data MD, which are then to be transformed to the overview image SI and to be inserted in a correlated manner to the respective position. The overview image SI is in the screen display that is in 3 is shown in the lower area. After the markings have been carried out in the left image I1 and in the right image I2, the marking data or the position data are automatically re-projected onto the overview image SI. The thus-modified overview image SI becomes together with the other images I1, I2 on the surface 30 shown. This presentation finally allows the physician once again to verify the position determination for validity or admissibility. If, for example, different target objects (eg different calcified foci) have been marked in the images, this is automatically visualized and recorded. Preferably, the user can set directly on the respective windows for displaying the images corrected or changed markers, which are then traced dynamically in the representation on all images (which requires an on the fly calculation). He can then change the markers in the stereo images until a correct target position has been determined. Optionally, a corresponding warning signal (audible and / or visual) is automatically output. Only after the doctor has confirmed the permissibility of the position determination by input of a Verificationssignals, the position data PD to the needle holder 10 forwarded.

In an advantageous embodiment of the invention, a plurality of stereotactic image pairs can be used for position determination. If necessary, these are also simultaneously and parallel on the user interface 30 shown. Alternatively, you can also take pictures of other imaging modalities 41 . 42 be used for position determination.

An important aspect of the present invention can be seen in that the overview recording SI is used for position determination. This is implemented by a so-called scout targeting functionality. An important advantage of this scout-targeting functionality is that the tissue structures (for example microcalcifications) of the breast B can be assigned in the different images (in the first image and in the second image of the stereotactic image pair). That is, the doctor can immediately see which calcifications belong together. This was previously not possible in the prior art. This is achieved by the marking data MD additionally being transformed to the third image, namely to the overview image SI. Thus, by checking the modified overview image SI, it can be ascertained whether different target objects (targets) have been marked erroneously in the stereo projections. In this case, the target in the overview image SI would be displayed in a wrong position.

As in 3 schematically illustrates the simultaneous representation of the three modified images on the user interface 30 each a merged set of image data and marker data MD. The marker data MD are also included in the overview image SI in a correlated manner. The modified overview image SI thus includes transformed and embedded marking data and can therefore be used to check the position determination or to calculate the same.

In 6 is a possible structure again shown schematically. In this case, the volume section to be biopsied is shown schematically as a cuboid and designated by the reference symbol B and is held by a compression plate K ₁ in a compressed state. In the upper area are three x-ray tubes or emitters 401 shown; Here, the middle is used to capture the scout image SI and the two outer to capture the stereo images with the respective (variable) angle range. In the detector 402 the incoming radiation is detected. In 6 is also the angle α drawn between the detector perpendicular and a dashed line connecting line between the isocenter of the rotation R and an emission point of the radiation of an X-ray emitter 401 is spanned.

In summary, the invention can be described as follows: The invention relates to an approach for targeting a target object in the context of a digital stereotactic biopsy, in which a scout-targeting functionality and a zoom-from-target functionality are implemented. With these functionalities, it is possible to use in addition to the stereotactic image pair also a modified overview image SI for determining the position of the needle N in the biopsy. In addition, settings for visualizing an image for the purpose of marking (in terms of zoom factor and pan range) are automatically transferred to the other image representations (the other image of the stereotactic image pair and the modified overview image). Thus, zoom factor and pan range need only be determined once (in one image). Thus, the number of user interactions (mouse clicks) can be reduced and the efficiency of the biopsy procedure can be increased significantly. The main advantages of the invention are a markedly improved quality of the position determination (by checking the position in the third image), a shortening of the procedure, and a quality improvement in which one of the three images instead of a quality-deficient other image of the three images can be used for position determination.

LIST OF REFERENCE NUMBERS

10

needle holder

N

needle

20

positioning device

30

user interface

40

mammography

41

ultrasound machine

42

other imaging units

BD

image data

MD

marker data

PD

positioning data

50

control module

60

biopsy device

B

Breast or object to be biopsied

K

compression system

K ₁

first compression plate

K ₂

second compression plate

401

 X-ray emitter

402

 X-ray detector

α

angle

R

Rotation isocenter

I1

first modified image of stereotactic image acquisition

I2

second modified image of stereotactic image acquisition

SI

Overview image or Scout Image

22

positioning module

24

read-in module

S1

Preparation: Patient positioning, positioning of the burst, compression of the chest

S2

Capture the overview image or Scout image

S3

Capturing the stereotactic image pair

S4

Representing the stereotactic images and the overview image for the purpose of marking and marking

S5

Automatic reading of marking data and calculation of position data

S6

Automatic transformation of the calculated position data into the overview picture

S7

Representing the modified overview image with the position data and the stereotactic images with the marker data

S8

Use the position data to calculate a biopsy needle holder positioning record

Claims (12)

Method for controlling a digital stereotactic biopsy using a mammography device ( 40 ), wherein an object of a patient for acquiring mammographic images is compressed, comprising the following method steps: - acquiring an overview image (SI), in which an object area to be biopsied (B) is shown - detecting at least two stereotactic images (I1, I2) comprising a first and a second image, from different directions - representing the acquired stereotactic images (I1, I2) with the overview image (SI) for the purpose of marking at least one target object - reading marker data (MD), which in at least two images a computer-aided input means are set to calculate three-dimensional position data of the target object - automatically transform the calculated three-dimensional position data of the target object into the overview image (SI) to create a modified overview image - automatically display the modified overview image (SI) with the transformed pos tion data and the two stereotactic images (I1, I2) with set marking data (MD) on a graphical user interface for position control, - providing a user interaction option for changing the marking data (MD) and re-displaying the images with the changed marking data (MD) and automatically changed Position data - positioning of a biopsy needle holder ( 10 ) with the position data. The method according to claim 1, wherein the method for marking comprises the following method steps: determining a zoom factor for zooming a displayed image area in the image to be marked determining a pan area for panning the zoomed image area, so that the target object is displayed centrally, automatically transmitting the image certain zoom factor and the particular Panbereiches on the other of the two detected stereotactic Images (I1, I2) and on the overview image (SI) to create a customized representation in which the overview image (SI) and the two stereotactic images (I1, I2) automatically with the same specific zoom factor and with the same specific pan area shown and the mark be used. Method according to one of the preceding method claims, in which the transformation comprises a correlated insertion of the marking data (MD) into the overview image (SI) or into further images or an overlaying of images. Method according to one of the preceding method claims, in which the marking is carried out in two images for the calculation of three-dimensional position data, preferably in both stereotactic images and / or in the overview image (SI) and in another image. Method according to one of the preceding method claims, in which a consistency check is automatically carried out, whether the three-dimensional position calculated from the two marking data sets (MD) after transformation into the overview image (SI) is displayed within a permissible range. Method according to one of the preceding method claims, in which a warning signal is automatically output and / or a prompt is automatically displayed on the user interface in order to correct the markings if an inconsistency in the marking data (MD) is detected in the images. Method according to one of the preceding method claims, in which an assignment functionality is provided which is based on a position comparison between more than 2 images and with which it is ensured that the target object which has been marked in the first image coincides with the target object which is in the the second picture has been marked, whereby a match signal can be output if they match. Method according to one of the preceding method claims, in which optionally an automatic quality check can be activated, which checks whether one of the two stereotactic images (I1, I2) is not present in sufficient image quality and in this case offers a user option which, after input of an acknowledgment signal, displays the overview image (SI) instead of the quality-deficient stereotactic image. Positioning device for a needle holder ( 10 ) of a biopsy device ( 60 ), comprising: - a read-in module ( 24 ), which is intended for reading position data that is used to calculate a target position for the positioning device ( 20 ) and which are determined by a method according to the preceding method claims - a position module ( 22 ), which is used to position the needle holder ( 10 ) is determined with a three-dimensional data set calculated from the position data. Control module for a positioning device ( 20 ) for a needle holder ( 10 ) of a biopsy device ( 60 ), which is intended for carrying out a method according to one of the preceding method claims. A computer program product that can be loaded into an internal memory of a digital computer and includes software routines that perform the steps of the preceding method claims when the software routines are executed on the digital computer. Biopsy device ( 60 ) for performing a digital stereotactic biopsy, comprising: - a control module ( 50 ) according to claim 10 - a positioning device ( 20 ) used for positioning a needle holder ( 10 ) is determined with a three-dimensional data record which is calculated from the marking data (MD) and - a user interface ( 30 ).

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