The image data receiving means generally used in mammogra- phy are x-ray films placed in cassettes. Such cassettes are available in several different types, depending e. g. on the manufacturer of the cassette and the type of imag- ing the cassette is designed for. Often there are also differences between cassettes according to whether the film used in them is intended to be developed in a dark- room or e. g. in a special film development device. These so-called daylight cassettes are gradually replacing dark- room cassettes.

The imaging apparatus used in mammography generally have in their imaging area a space with at least one feed/eject opening, a cassette tunnel or equivalent, into which a cassette loaded with a film is entered and where it is po- sitioned at a desired imaging location and from where it is removed and taken to a separate labeling stage. In many imaging apparatus the cassette tunnel is so implemented that its open end or ends form a cassette feed/eject open- ing. When both ends of the tunnel are open, the cassette can be moved in the tunnel by pushing it from one end of the tunnel and pulling from the other. Moreover, in some devices the tunnel wall is provided with additional holes to make it easier to move the cassette. Patent application FI 19992538 submitted simultaneously with the present ap-

plication describes solutions for moving the cassettes in the cassette tunnels of mammography apparatus.

Traditionally, the recording of imaging parameters, pa- tient information and other possible data on the X-ray film has been performed by writing these data manually ei- ther on the film itself or on a label or equivalent which can be glued or otherwise attached to the film. Later on, special labeling devices have been developed, by means of which it is possible to print, project or otherwise record the desired data on the film e. g. via an openable and closeable labeling window provided in the film cassette.

The data to be entered on the film may be supplied to the apparatus via a keyboard, but the apparatus may also be provided with interfaces for direct transfer of the infor- mation or part of it from the imaging apparatus and/or from an electronic database of personal information.

As for state-of-the-art labeling of film cassettes, refer- ence can be made e. g. to US patent publications 5,333,170, 5,416,823 and 5,694,450.

Recording patient information, dates, imaging parameters and projections etc. on a film or equivalent is an essen- tial part of the imaging process. Especially in mammo- graphic screening studies, innumerable images of different projections for a large number of patients are obtained, which is why there is a great risk of labeling errors occurring due to human factors. When the actions related to labeling are carried out as an operation physically separate from the actual imaging, the cassettes may be interchanged when being taken from the imaging apparatus to the labeling device. Thus, information of a wrong patient and/or wrong imaging parameters may be entered on the film. And when human activities are concerned, it may even happen that some or even all of the data is not recorded at all when the labeling of an individual cassette or a whole batch of films is accidentally ne- glected e. g. as a result of a lapse of memory. On the

result of a lapse of memory. On the whole, labeling of the films is an operation that requires accurate management and contributes for its part to the total duration of the imaging process. Despite their many definite advantages, none of the prior-art labeling devices, even those with a high degree of automation, eliminate the possibility of errors due to human factors as described above.

The object of the invention is to eliminate the above- mentioned drawbacks in order to reduce errors occurring in the labeling of films and to enable a more efficient utilization of time. Especially the object of the inven- tion is to achieve an arrangement and a method that will substantially reduce the possibility of labeling errors occurring due to human mistakes and lapses of memory.

Another object of the invention is to improve patient safety by reducing the possibility of faulty diagnoses oc- curring as a result of erroneous labeling.

A further object of the invention is to improve radiation hygiene by reducing the need to take new pictures on the grounds that the object imaged cannot be identified due to erroneous, doubtful and/or totally forgotten labeling.

A further object of the invention is to facilitate the work of persons involved in the imaging process, by sim- plifying the difficult labeling process.

One of the objects of the invention is also to enable es- pecially more efficient mammographic screening studies by providing means for shortening the time needed between ra- diation exposures.

Especially an object of the invention is to achieve an ar- rangement in which the recording of patient information and imaging parameters on the film, which constitutes an essential part of the imaging process and which in prior-

art solutions is implemented as a separate operation, can be performed automatically in the imaging apparatus in connection with the imaging process.

The fundamental idea of the invention described in the present application is to provide a mammography apparatus with means whereby the image data receiving means can be labeled already in the mammography apparatus, in the first place in its cassette tunnel or a similar space, either by using separate control means and/or automatically. As the x-ray apparatus labels the cassette before the latter is removed from the x-ray apparatus, the imaging process be- comes more effective as one of the operations that has been part of it will be eliminated.

In the following, some of the preferred embodiments of the invention will be described in more detail with reference to the attached drawings. However, the invention is not intended to be exclusively limited to these embodiments; instead, its exact essential features are presented in the attached claims. In the attached drawings, Fig. 1 presents a typical mammography x-ray apparatus.

Fig. 2 presents a typical C-arm structure in the mammogra- phy apparatus Fig. 3 presents an arrangement according to the invention for labeling means to be fitted in the cassette tunnel of a mammography apparatus, Fig. 4 presents one arrangement for moving the image data receiving means used in mammography, and Fig. 5 presents another arrangement according to the in- vention for labeling means to be fitted in the cassette tunnel of the mammography apparatus.

The mammography x-ray apparatus 1 presented in Fig. 1 con- sists of a frame part 11 and a C-arm 12 connected to it.

Typically, placed at opposite ends of the C-arm 12 are a radiation source 13 and an image data receiving means 14', which is located e. g. inside a so-called bottom shelf structure 14. These imaging means 13,14', being placed inside the casing of the apparatus, are not actually visi- ble in Fig. 1. In addition, placed in the area between these imaging means 13,14', typically near the image data receiving means 14', are means 15,16 for positioning the object to be imaged in the imaging area. Typically, the C- arm 12 can be both moved vertically and horizontally in relation to the means 15,16 for positioning the object to be imaged and rotated in relation to the frame part 11.

The positioning means 15,16 typically consist of an upper compression plate 15 and a lower compression plate 16, and the lower compression plate 16 may also be arranged to function as a so-called bucky."Bucky"means a grid struc- ture placed between the tissue to be imaged and the image data receiving means to prevent radiation scattered from the tissue from reaching the image data receiving means.

Fig. 2 presents one C-arm structure 12 used in mammography apparatus. The C-arm 12 in Fig. 2 differs from the struc- ture in Fig. 1 especially in respect of the way in which the cassette tunnel or similar space 17 has been arranged in the imaging area of the apparatus. The solution illus- trated in Fig. 1, in which both ends of the cassette tun- nel 17 are closed and a cassette 14'is entered into the cassette tunnel 17 by driving the bottom shelf structure 14 downwards so that a space is formed between it and the lower compression plate 16, allowing the cassette 14'to be inserted into the cassette tunnel 17 via this space from above, is fairly seldom used in mammography appara- tus. Fig. 2 presents perhaps a more typical solution, in which at least one end of the cassette tunnel 17 is open, allowing the cassette 14'to be inserted directly into the

tunnel 17 from the side of the structure, without requir- ing operation of the means for driving the C-arm 12.

Generally speaking, in mammography systems there are used more or less integrated structures of several different types for forming the assembly consisting of the bottom shelf, lower compression plate and bucky/grid 14,16 and the associated cassette tunnel or similar space 17. For example, in the solution illustrated in Fig. 2, the cas- sette tunnel 17 has been integrated as a part of the lower compression plate/bucky structure 16 of the apparatus.

Anyway, all cassette tunnel solutions have the common aim of bringing one edge of the cassette tunnel 17 as close as possible to that wall 18 of the bottom shelf or similar structure 14,16 which comes into contact with the chest during imaging, because the image data receiving means must be so placed in the imaging area as to allow a maxi- mal amount of tissue even in the region of the sternum and armpit to be imaged.

When the cassette tunnel 17 has been arranged to be loaded in a horizontal plane as shown in Fig. 2, its feed/eject opening is generally disposed in a lateral location as seen from the direction 18 from which the tissue to be im- aged is entered. This obviates the need for re-positioning the object to be imaged, which is an awkward operation that may be unpleasant to the person being imaged, only because a change of cassette 14'is needed.

Fig. 3 presents an arrangement according to the invention for labeling means 3 to be fitted in the cassette tunnel of a mammography apparatus, said means comprising a frame part 31 and guide rails 32 mounted on said frame part 31, on which guide rails a carriage 33 with a solenoid 34 at- tached to it can move. The carriage is moved by means of a screw conveyor 35 rotated by a motor 36. In addition, the labeling device presented in Fig. 3 comprises a display or

other recording means 37, by means of which the desired information can be projected or printed onto the film.

A labeling means 3 as illustrated in Fig. 3 can be placed in conjunction with the cassette tunnel 17 by mounting it e. g. on the bottom shelf 14. The location selected for its placement may be e. g. a position where labeling can be performed while the cassette is in its typical imaging po- sition, or it may be a separate labeling position in the tunnel in which the desired markings can be made. The la- beling means may also be so mounted that their horizontal position in relation to the cassette tunnel can be changed. Thus, the cassette tunnel can be provided with more than one labeling position to allow labeling of e. g. cassettes of different sizes and/or different types in which the labeling window is located at different posi- tions. When the cassette has been positioned in its label- ing position, a counterpart comprised in its window struc- ture meets the solenoid 34 as it is moving from its rest position to the labeling position. Thus, the shutter of the labeling window can be opened and closed by driving the carriage 33 along the guide rails 32 by means of the motor 35 and the screw conveyor 35.

The recording means 37 may be e. g. a liquid crystal dis- play, from which the desired data can be projected onto the film in a known manner by using a lamp (not shown in Fig. 3) placed behind the display. When a liquid crystal display is used, it is preferably so disposed in the la- beling means structure that the display 37 can be moved as close to the film as possible. In this case, it is may not be necessary to provide any separate optical devices be- tween the display and the film to ensure a successful la- beling exposure, although a suitable lens is generally re- quired. Naturally, there are many other techniques, such as e. g. optical fibers, that may be used to implement the display.

The labeling of the film can naturally also be made by us- ing a so-called scanning technique. In this case, the la- beling window structure of the cassette does not necessar- ily have to be provided with an actual shutter that can be opened/closed; instead, e. g. a shutter with a narrow, pos- sibly closeable aperture which can be scanned over the la- beling window, can be used. In a scanning technique, the essential feature is that the labeling area of the film is scanned using a printing or exposure head or an equivalent element. The scanning is preferably implemented using re- cording heads that expose, or by other way mark, the film in only one dimension, while another dimension of the marking is accomplished by the scanning movement. For ex- ample, a single-row LED display is considerably cheaper than a corresponding matrix display. This naturally also applies to many other technical solutions, such as optical fibers.

Fig. 4 presents an arrangement described in application FI 19992538 submitted simultaneously with the present appli- cation, which allows the entry and ejection and also other movements of the cassette, if desired, of a film cassette 14'in the cassette tunnel 17. In the embodiment illus- trated in Fig. 4, the arrangement for moving the cassette 14'in the cassette tunnel 17 comprises a bottom shelf 14, depicted in a sectioned view in the figure, means 19 for moving the cassette 14', a button 20 for starting the ejection of the cassette 14', and a bucky 16. The means 19 for moving the cassette 14'comprise a driving roller 21, a driving roller motor 21 not visible in the figure, being placed below the bottom shelf 14, and a turning shaft 22 functionally connecting the roller 21 and its motor and provided with a gearing 22'. In the arrangement in Fig. 3, the cassette tunnel 17 is so implemented that it forms a part of the bucky 16, with an opening/openings at its sides serving as cassette 14'feed/eject openings. The means 19 for moving the cassette 14'are mounted on a car- riage 23 which can be moved along guide rails 24 and which

is connected to a spring 25 continuously tending to pull it by means of a drawing band 26 toward that end 18 of the bucky 16 which comes into contact with the chest. The bot- tom of the bottom shelf 14 is also provided with an elon- gated aperture, not shown in Fig. 4, laid in a direction parallel to the guide rails 24, the shaft 22 of the driv- ing roller 21 going through this aperture. Thus, the means 19 for moving the cassette 14'can move in the direction of this aperture and the guide rails 24. The cassette tun- nel 17, e. g. its bottom, may additionally be provided with one or more sensors 27, which are connected to the control means (not shown in Fig. 4) of the apparatus to probe the position of the cassette 14'in the cassette tunnel 17.

Disposed on the side opposite to that wall 18 of the bucky 16 that comes into contact with the chest of the object to be imaged is arranged an elongated cut-out or groove 28 substantially parallel to the guide rails 24, into which the shaft of the driving roller 21 is directed when the bucky 16 is being mounted on the bottom shelf 14 from the direction of the wall 18 placed against the chest. The length of this cut-out 28 is so designed that it will po- sition the driving roller 21 in relation to the cassette tunnel 17 so that the circumference of the roller 21 will come into contact with the side wall of the cassette 14' when the latter is in the cassette tunnel 17. A spring 25 continuously draws the means 19 for moving the cassette 14'toward the cassette 14', ensuring that a frictional force sufficient for converting the rotational motion of the roller 21 into a linear movement of the cassette 14' exists between the sidewall of the cassette 14'and the driving roller 21. In the solution illustrated in Fig. 4, the guide slot 28 and guide rails 24 for guiding the bucky 16 are disposed at an angle substantially perpendicular to the feed direction of the cassette 14'in the cassette tunnel 17, but naturally they may also be arranged at a different angle.

The arrangement illustrated in Fig. 4 may function e. g. as follows. When a cassette 14'is fed through the feed open- ing into the cassette tunnel 17, the control system of the apparatus detects by means of a sensor 27 placed in the tunnel 17 that a cassette 14'has been entered in the tun- nel 17 and starts the drive motor of the driving roller 21. As the cassette 14'is pushed further in, its rear edge meets the driving roller 21, which begins to draw the cassette 14'into the tunnel 17, whereupon the person in- serting the cassette 14'can release his/her grip of it.

Preferably, into the cassette tunnel 17 open at both of its ends and a sensor 27 is provided in the area of both of the feed openings, in which case the control system will control the drive motor of the driving roller 21 to rotate in the appropriate direction to draw the cassette 14'into the tunnel.

Disposed at a suitable location at the other end relative to the feed opening of the tunnel 17, there may be another sensor 27 (not shown in the figure) to detect the edge of the cassette 14', allowing the control system either to stop the motor or to move the cassette 14'from this de- tection point to a given other imaging position as re- quired in each case. In most cases, this position is the location where the midpoint of the cassette 14'lies on the center axis of the field of rays used for imaging. Af- ter the cassette 14'has been correctly positioned, the control system gives a permission for starting the actual imaging process.

Upon completion of the imaging process, the means 19 for moving the cassette 14'drive the cassette 14'out of the cassette tunnel 17 either on the basis of a signal ob- tained from a cassette eject button 20 or automatically e. g. via a predetermined eject opening. The arrangement preferably comprises two cassette eject buttons 20, which are disposed substantially near each end opening of the cassette tunnel 17. The control system identifies which

one of the buttons 20 has been pressed and drives the cas- sette 14'out of the tunnel 17 via the eject opening cor- responding to this button 20. Labeling can then be per- formed automatically or separately by control via the con- trol means, either in the imaging position or in a sepa- rate labeling position, to which the cassette 14'is driven before being ejected out of the tunnel 17.

For example, means for moving the cassette in the cassette tunnel as illustrated in Fig. 4 can be utilized in a la- beling arrangement according to the present application by using the means 19 for moving the cassette 14'even for implementing the movements needed to open and close the shutter of the labeling window of the cassette 14', in which case any separate means for accomplishing this move- ment are not needed and they can be omitted. Thus, the means 3 for the labeling of films presented in Fig. 5 com- prises a frame part 31, a carriage 33 functionally con- nected to the frame part 31 via guide rails 32, a screw conveyor 35 for moving the carriage and a motor 36 driving the screw conveyor. Mounted on the carriage is a display 27 and a contact means 38, such as a pin or equivalent.

The means for moving the cassette 14'can now be utilized for opening and closing the shutter of the labeling window of the cassette so that when the cassette is in its label- ing position, its labeling window is located at a position where, as the carriage 33 is being raised, the contact means 38 meets the counterpart provided in the shutter structure of the labeling window of the cassette 14'.

Thus, the labeling window of the cassette can be opened and closed by moving the cassette itself by the arrange- ment of the invention.

If the utilization of the movement of the cassette 14'is combined with a film marking technique that does not re- quire the display 37 or equivalent element to be moved closer to and farther away from the cassette 14', then the solution illustrated in Fig. 5 can be further considerably

simplified. In this case, an arrangement in which the dis- play 37 or equivalent element is immovably mounted di- rectly on the frame part 31 and in which the contact ele- ment 38 used is e. g. a solenoid 34 as in fig. 3 will be sufficient. And if scanning is used for the labeling func- tion, then, depending on the recording technique, even a contact element 34,38 may be unnecessary. This is because the above-described movements for opening/closing the la- beling window can be replaced with a solution which uses a labeling window substantially impermeable to visible light wavelengths and a recording element producing information that is capable of penetrating the cassette's labeling window impermeable to visible light or that can otherwise, e. g. in a converted form, be passed through it.

The cassette tunnel or similar space can also be provided with cassette moving means by which the cassette can be moved in the tunnel both in its feed direction and in a direction substantially perpendicular to the feed direc- tion. As the cassette can be moved in a plane during imag- ing, this creates possibilities to utilize the mammo- graphic imaging apparatus for more diversiform imaging, but this possibility of cassette motion can also be util- ized to operate the cassette moving means in a new way in co-action with the film labeling means, because the cas- sette tunnel, labeling means and means for moving the cas- sette in a plane can be arranged in a suitable manner to permit the use of cassettes of different types and sizes in the imaging apparatus. As the labeling window can be brought to the correct labeling position regardless of the cassette being used, it will be possible to use cassettes of different types and sizes even if the labeling means have been implemented as a system working in a fixed posi- tion.

The labeling arrangement can be connected to a microcom- puter to allow the input of data to be recorded on the film. The arrangement is preferably so implemented that the microcomputer and the imaging apparatus as well as

e. g. the data network of a hospital will be able to ex- change and transmit information to each other, thus mini- mizing the need for manually inputting data to be recorded on the film and sending such data to a processor card typically comprised in the labeling means. After the imag- ing process, the imaging parameters for the imaging proc- ess in question can also be automatically sent to the processor card. By using a desired automatic system or e. g. the control system of the imaging apparatus, the cas- sette can be moved immediately upon completion of imaging to the labeling position, where the arrangement of the in- vention e. g. opens the shutter of the labeling aperture of the cassette, projects or prints the desired data and closes the shutter, whereupon the cassette is ready to be taken to a development stage.

The advantages of the arrangement of the invention are clearly visible in screening studies as mentioned above, in which the arrangements according to preferred embodi- ments of the invention can be utilized e. g. as follows: After the first imaging operation, the operator of the im- aging apparatus emerges from behind the radiation shield and steps in front of the apparatus, holding the next cas- sette ready in his hand, presses the cassette eject switch on that side where he wants the cassette to come out of the cassette tunnel, inserts the new cassette via the opening of the cassette tunnel, whereupon the cassette is automatically positioned in the correct position, turns the C-arm of the device into the next projection angle and, if necessary, corrects the position of the object to be imaged, after which everything is ready for the next image to be taken. When the imaging apparatus is provided with means for automatic labeling of the film according to the invention before it is driven out of the cassette tun- nel, the imaging work becomes considerably more effective than before as the time spent on supplementary work asso- ciated with the imaging process is substantially reduced.

The amount of manual work to be done in connection with the arrangement of the invention can be further reduced by adding to the cassette tunnel feed opening a cassette feed magazine operated by any known technique. The arrangement of the invention can even be thought of as being developed as far as creating a mammography imaging line that is com- pletely automated except for the positioning of the object to be imaged, the first part of which line could consist of a station for loading cassettes with film, said station either simultaneously functioning as a cassette feed maga- zine of the mammography apparatus or being connected to a cassette feed magazine via a cassette conveyor line, from which magazine the cassette is fed into the cassette tun- nel of the mammography apparatus, where the cassette mov- ing means provided in the tunnel take care of the cassette movements needed for its positioning in connection with imaging, for possible cassette motion and labeling during imaging and finally driving the cassette out of the cas- sette tunnel, either from the same side as or from a dif- ferent side than where the cassette was inserted into the tunnel, in which case, depending on the solution, the cas- sette is conveyed either via the same aforementioned cas- sette conveyor line or via a separate line to a film de- velopment unit, which comprises means known in themselves for automatic removal of the film from the cassette and for its development.

In the foregoing, in the first place only solutions based on a certain kind of labeling means and a certain kind of labeling technique have been described in detail by way of example, but the arrangement and method of the invention can naturally be implemented applying other solutions known in themselves. The invention could also be thought of as being used in conjunction with an imaging apparatus in which the cassette tunnel itself functions in a way as a film cassette, in other words, in which only a film is fed into the cassette tunnel and a labeling window is pro- vided in conjunction with a wall of the cassette tunnel.

The examples presented above are not meant to be an ex- haustive list of concrete and preferred ways of applying the invention; instead, its embodiments may vary within the scope of the inventive idea defined in the following claims.