Abstract:
A device for reading out X-ray information stored in a phosphor plate for simplified and solid guiding and/or holding of phosphor plates, with at the same time a high degree of compactness, includes: a device for holding and/or conveying the phosphor plate in an orientation inclined by an inclination angle α in relation to a vertical in which the phosphor plate is flat in form; and a read-out device for reading out the flat phosphor plate inclined by the inclination angle α in relation to the vertical.

Description:
The invention relates to a device and to a corresponding process for reading out X-ray information stored in a phosphor plate. 
   Generic devices for this process are used, in particular for medical purposes, in the field of computer radiography (CR). Here, X-rays are recorded in so-called storage phosphors, whereby the X-ray radiation passing through an object, for example a patient, is stored as a latent picture in a storage phosphor layer. In order to read out the stored picture, the storage phosphor layer is irradiated with stimulation light, and so stimulated into emitting emission light, the intensity of which is dependent upon the respectively stored picture information. The emission light is collected by an optical detector and converted into electric signals which can be further processed as required and shown on a monitor or on a corresponding display unit, such as a printer. 
   U.S. Pat. No. 6,437,359, herein incorporated by reference in its entirety for background information only, describes a device wherein a phosphor plate located within a cassette is removed from the cassette using an extraction rod and conveyed in a vertical direction past a read-out station. In order to guide the phosphor plate, plate guides and guide rolls are provided. So that the storage phosphor plate lies against the plate guides or guide rolls during conveyance, the extraction rod is rotated slightly, so that the storage phosphor plate is pressed against the plate guides or the guide rolls. This type of mechanism for rotating the extraction rod is relatively complex and prone to interference. 
   SUMMARY OF THE INVENTION 
   It is the object of the invention to provide a device and a corresponding process for reading out storage phosphor plates with simplified and solid guiding or holding of the phosphor plates with at the same time a high degree of compactness. 
   The device is characterized by a device for holding and/or conveying the phosphor plate in an orientation inclined by an inclination angle in relation to the vertical in which the phosphor plate is flat in form, and by a read-out device for reading out the flat phosphor plate inclined by the inclination angle in relation to the vertical. 
   With the process the storage, phosphor plate is read out while it is inclined by an inclination angle in relation to the vertical and is flat in form. 
   Due to the inclination of the storage phosphor plate in relation to the vertical according to the invention, it is possible for the phosphor plate to be pressed against the corresponding support and/or guide elements due to its own weight, and to be supported without any the need for any additional pressing mechanism. In this way, the mechanism required for the secure conveyance and/or holding of the phosphor plate is simplified. Because the phosphor plate must in general only be inclined slightly, e.g. by a few degrees, in relation to the vertical in order to achieve the advantages of the invention, at the same time a high degree of compactness is guaranteed in comparison to known devices whereby storage phosphor plates are read out in a horizontal orientation. 
   Preferably, in order to hold and/or convey the storage phosphor plate, the device includes one or more support elements which are arranged in such a way that the phosphor plate inclined in relation to the vertical can lie on the support elements due to its own weight. 
   The support elements can be guide elements such as guiding skids or guide rolls which guide the storage phosphor plate during its conveyance. 
   In addition or alternatively, the support elements include a flat support inclined in relation to the vertical on which the phosphor plate can lie, in particular during read-out and/or during conveyance. In this way it is guaranteed in a simple manner that the phosphor plate maintains a flat form, in particular during read-out and/or during conveyance so that the mechanical stress applied to the phosphor plate is reduced to a minimum. 
   Preferably, the support is provided with an attracting device so that the phosphor plate can be pulled onto the support. The phosphor plate is thus held on the support by its own weight and additionally by the attracting device so that the inclined orientation in relation to the vertical of the phosphor plate is guaranteed with a particularly high degree of reliability. The attracting device can include suction nozzles, for example, which are connected to a vacuum pump. The storage phosphor plate is thus pulled onto the support by suction. Alternatively however, magnets can also be provided so that a storage phosphor plate provided with corresponding magnetic substances can be pulled by the support. 
   With another embodiment of the invention, a first drive device is provided which moves the read-out device during read-out relative to the phosphor plate which is inclined in relation to the vertical. Preferably, the plate lies here on the flat support. When using so-called line scanners a whole line of the phosphor plate can be read out by the read-out device at one time, and a particularly compact structure of the device is achieved. 
   In an alternative embodiment of the invention, a second drive device is provided which moves the phosphor plate inclined in relation to the vertical, in particular together with the flat support, during read-out, relative to the read-out device. This embodiment is particularly advantageous if the read-out device includes a so-called flying spot scanner with which an individual laser beam is deflected by a rotating mirror, and thus samples, point by point, individual lines of the phosphor plate to be read out. Because this type of scanner generally react sensitively to vibration, it is often integrated and fixed with the respective read-out devices. 
   It is also preferred to provide an insertion device into which a cassette, within which the phosphor plate is located, can be inserted, the insertion device being designed in such a way that the inserted cassette and/or the phosphor plate located within the cassette, is inclined in relation to the vertical. In this way it is ensured that when being removed from the cassette, the storage phosphor plate located within the cassette can lie on an inner wide side of the cassette due to its own weight, and be guided by the same. In this way, when removing the storage phosphor plate from the cassette, any additional guide elements can be dispensed with. 
   Conveyance of the phosphor plate in the device according to the invention preferably also takes place on a conveyance level inclined in relation to the vertical. In this way it is ensured that the flat storage phosphor plate is not bent or buckled during its conveyance so that the mechanical stress applied to the storage phosphor plate during its conveyance is greatly reduced. Preferably, the phosphor plate located within the cassette lies on the conveyance level so that the phosphor plate is not bent on the conveyance level when being removed from the cassette and during conveyance. 
   According to the invention, the inclination angle of the phosphor plate and/or the support and/or the conveyance level and/or the inserted cassette or the phosphor plate located within the cassette has a value of between 3° and 15°. In this way, a high degree of reliability is guaranteed during the read-out and conveyance of the phosphor plate, also with a high degree of compactness. 
   Additional features and advantages of the invention are given in the following description of preferred embodiments and examples of applications, wherein reference is made to the attached drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a) a highly schematised representation of a device according to the invention at a first point in time in a front view and b) in a side view; 
       FIG. 2  shows a) the device illustrated in  FIG. 1  at a second point in time in a front view and b) in a side view; 
       FIG. 3  shows a cross-section through an insertion device in a region of a stop in a front view; 
       FIG. 4  shows a cross-section through an insertion device with a cassette located within the insertion device in a side view; 
       FIG. 5  shows a cross-section through an insertion device in a region of a fixing element and a closure mechanism in a front view; 
       FIG. 6  shows a cross-section through an insertion device in a region of a fixing element and a closure mechanism in an overhead view; 
       FIG. 7  shows a preferred embodiment of a support; 
       FIG. 8  shows in a) to c) another embodiment of a device according to the invention in a side view at a first, second and third point in time. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1   a  and  1   b  show an example of the device  1  according to the invention in a front and a side view. In the upper region of the housing of the device  1  there is an insertion device which in this example is in the form of a cassette holding slot  4 . The cassette holding slot  4  is designed such that a cassette  2  inserted into the slot together with the storage phosphor plate  3  located within the same is inclined by an inclination angle in relation to the vertical. The inclination angle is preferably between approximately 3° and 15°. 
   In the lower region of the cassette holding slot  4  an oblong insertion opening  5  is provided through which the phosphor plate  3  located within the cassette  2  can be conveyed into the inside of the housing of the device  1 . The insertion opening  5  is oblong or slit-shaped in form, its length being at least as great as the corresponding length of the largest phosphor plate format to be read out in the device  1 . The width of the insertion opening  5  is selected to be sufficiently great so that the phosphor plate  3  is not obstructed by the insertion opening  5  when removing it from the cassette  2 , even with small position fluctuations. 
   The cassette  2  lies with a first narrow side  6  on the floor of the cassette holding slot  4 , and lies with a second narrow side  7  against a stop  8  which is provided at one end of the cassette holding slot  4 . 
   Section A marked in  FIG. 1   a  is shown in enlarged form in  FIG. 3 . On the stop  8  a protrusion  11  is provided which can engage into a corresponding, complementary indentation  12  in the cassette  2  and fix this in this way in the cassette holding slot  4 . While the cassette  2  is being pushed against the stop  8  in direction K as it is being inserted into the cassette holding slot  4  and the protrusion  11  can engage in the indentation  12  in the cassette  2 , a linear sensing device  15  is activated at the same time by the lower corner of the cassette  2 , and the sensing device sends a signal corresponding to the respective position of the cassette  2 . This signal determines whether the cassette  2  is already lying fully against the stop  8 . 
   If for example the cassette  2  is moved with a wrong narrow side in direction K towards the stop  8 , the protrusion  11  of the stop  8  cannot engage in a corresponding indentation in the cassette  2  so that the cassette  2  comes to stand approximately at the height of the protrusion  11 . In this case, the linear sensing device  15  does not send a correspondingly high signal so that it is understood that the inserted cassette  2  is falsely orientated. In this case, a corresponding error signal is issued in a suitable display unit on the device. 
   Furthermore, the linear sensing device  15  is used to determine the exact position of the cassette  2  in relation to the stop  8 , or the position of the insertion opening  5 . The linear sensing device  15  can thus also register a slight tipping of the cassette  2  in relation to the horizontal. 
   The combination of the protrusion  11  against the stop  8  and the corresponding indentation  12  in the cassette  2  on the one hand with the linear sensing device  15  in the region of the stop  8  on the other hand thus makes it possible in a simple way to provide reliable recognition of the correct orientation and exact position of an inserted cassette  2 . Only when the linear sensing device  15  sends a corresponding signal will further process steps be initiated for the processing of the phosphor plate  3  located within the cassette  2 . 
   In a next step the cassette is fixed in the region of the third narrow side  9  of the cassette  2  lying opposite the second narrow side  7  in conjunction with a light seal on the insertion opening  5 . In the following this is described in greater detail with reference to  FIGS. 4 to 6 . 
     FIG. 5  shows section B marked in  FIG. 1   a  in enlarged form. A fixing element  20  attached to an endless belt  23  is moved in the longitudinal direction L of the insertion opening  5  towards the third narrow side  9  of the cassette  2 , and here can engage in another indentation  22  of the cassette  2 , and in this way fix the cassette  2  by form-locking. By using a corresponding pressing force, a force closure fixing of the cassette  2  is achieved at the same time, in particular by pressing onto the stop  8  located on the opposite second narrow side  7 . The light seal of the insertion opening  5  is created here both by the first narrow side  6  of the cassette  2  which covers a first section  5   a  of the insertion opening  5  so as to prevent light penetration, and by a closure mechanism  21  which is formed by a part of the endless belt  23  and covers a second section  5   b  of the insertion opening  5 . 
   Alternatively, or in addition, the first section  5   a  of the insertion opening  5  can be sealed against light penetration by other suitable means. One possible variation is shown in  FIG. 4  which shows a cross-section through the insertion device  4  with the cassette  2  located within it, along the cross-section level C (see  FIG. 5 ) in a side view. In this example, sealing lips  13  are provided which can extend sideways into the inside of the cassette holding slot  4  and lie against the wide sides  14  of the cassette  2 . In this example, the sealing lips  13  are in the form of hollow lips and preferably respectively run parallel to the longitudinal direction L (see  FIG. 5 ) of the insertion opening  5  or to the first narrow side  6  of the cassette  2 . 
   In  FIG. 4  one can also see the indentation  22  in which the fixing element  20  (see  FIG. 5 ) can engage and thus fix the cassette  2  by form locking and, if required, force closure. 
   In the example given in  FIG. 5 , photo sensors  26  to  28  are also provided which can be interrupted by a tab  29  attached to the fixing element  20 . These photo sensors  26  to  28  are correspondingly allocated to the different cassette formats to be processed so that a photo sensor  26 ,  27  or  28  is only interrupted by the tab  29  and a corresponding signal sent if a cassette permissible for this device with a corresponding format is inserted in the correct position and with the right orientation. In association with the stop  8  described in greater detail in connection with  FIG. 3 , even greater reliability for the recognition of the right orientation and correct position of the respectively inserted cassette  2  is guaranteed by the photo sensors  26 ,  27  and  28 . 
   The endless belt  23  is preferably in the form of a toothed belt. In order to guide and drive the endless belt  23 , rollers  31  and  32  are provided, one of the rollers  31  or  32  being in the form of a roller drive which can move the endless belt  23  and so also the closure mechanism  21  as well as the fixing element  20  attached to it parallel to the longitudinal direction L of the insertion opening  5 . 
     FIG. 6  shows an overhead view of the section of the device according to the invention shown in  FIG. 5 . As can be seen, the endless belt  23  has a cut-out  24  in the region of the inserted cassette  2  so that this can run on both sides of the cassette  2 . On one end of the cut-out  24  the fixing element  20  is attached, which together with the closure mechanism  21  attached onto this can be moved toward the cassette  2  or away from the cassette  2 . The fixing element  20  has a region  20   a  which runs at a slant or in the form of a wedge, so that the cassette  2  is pressed in a direction R against a wall of the cassette holding slot  4  when the fixing element  20  extends into the indentation  22  in the cassette  2 . 
   The fixing element  20  is preferably fastened onto a slide which is movably mounted with rollers on tracks running on both sides of the cassette  2  (not shown). 
   On the edge of the phosphor plate  3  (see  FIG. 1   a ) there is an electronic storage unit  10  for storing data such as data relating to the format of the cassette  2 , the phosphor plate  3  and the total thickness of the phosphor plate  3  which is made up from a substrate material and a phosphor layer located on top of the substrate material, and typically having a total thickness of between approximately 1 and 3 mm. 
   The electronic storage unit  10  is preferably in the form of a so-called RF-Tag which can be read out by an RF reader  25  by radio frequency radiation. The data on the format of the cassette  2  read out from the electronic storage unit  10  can be compared with the information obtained from the photo sensors  26  to  28  and tested for plausibility. If there is, for example, a non-desirable object between the third narrow side  9  of the cassette  2  and the fixing element  20 , such as a hand or a finger of a user, the photo sensor signal obtained here is not consistent with the cassette format established in the electronic storage unit  10 . In this case, the fixing process can be interrupted, and a corresponding error signal is issued. 
   Furthermore, a so-called clamping force sensor (not shown) can be positioned on the circulating endless belt  23 , and this can register the tension of the endless belt  23  when fixing the cassette  2 . By determining the belt tension, the endless belt  23  drive can be controlled in such a way that the fixing element  20  presses with a pre-determinable force onto the third narrow side  9  of the cassette  2 , and in so doing, fixes it. Typical forces here are those between 10 and 100 N. In this way, even with cassettes of different formats, a format-independent pressing force and fixing of the cassette in the cassette holding slot  4  is achieved. Furthermore, it can be guaranteed by a corresponding specification of the pressing force that the cassette  2  is not damaged by excessive forces while being fixed. Furthermore, the risk of injury is reduced in cases where a body part, such as a hand or a finger of a user inadvertently comes between the cassette  2  and the fixing element  20  or stop  8 . 
   On the first narrow side  6  of the cassette  2  a flap (not shown) is provided which closes the cassette  2  to form a light seal. This flap is unlocked with a suitable opening mechanism (not shown), the phosphor plate  3  at the same time being locked in the cassette  2  so that it cannot fall out of the cassette  2 . This type of cassette with a corresponding unlocking and locking mechanism is described in greater detail in the European patent application number 01104202.1 herein incorporated by reference in its entirety for background information only. 
   Preferably, the opening of the flap, which preferably takes place by a simple translatory movement of corresponding opening pins in the region of the first narrow side  6  of the cassette  2 , is mechanically coupled with the seal on the wide sides  14  of the cassette  2  by the sealing lips  13  already described above (see  FIG. 4 ). 
   A conveyance device  15  can now approach the cassette  2  and the phosphor plate  3  located within it, and grasp the latter by means of grasping arms  16 . Hooks and/or cut-outs suitable for this are provided on the phosphor plate  3 , as described in greater detail in particular in the published European patent applications EP 1 321 804 and EP 1 324 118, both herein incorporated by reference in their entirety for background information only. 
   The phosphor plate  3  which is still locked in the cassette  2  can now be unlocked and removed from the cassette  2  by a downwards movement of the conveyance device  15  in conveyance direction T. The conveyance direction T here also involves a final inclination angle in relation to the vertical, and is preferably selected such that the phosphor plate  3  can be removed from the cassette and conveyed essentially without any change in direction, for instance on just one conveyance level. 
   The phosphor plate  3  is now conveyed in conveyance direction T to a support  40 . Spacers  41  are provided on the support  40  which are extended over the support  40  during conveyance of the phosphor plate  3 . Due to its own weight, the phosphor plate  3  then lies on the spacers  41  and is carried by these with very little friction. 
   The structure of a support  40  formed in this way is shown in detail in  FIG. 7 . As can be seen, as well as the already mentioned retractable and extendable spacers  41 , the support  40  has several segments  42  by means of which the storage phosphor plate  3  located on the support  40  can be pulled onto the support  40 . In the example shown here, the individual segments  42  each include a rubber border strip  43  and a suction nozzle  44  within each segment  42  which is connected to a vacuum pump (not shown). By an appropriate arrangement of segments  42  of different sizes, the attracting and suction effect of which can preferably be controlled separately, it is possible to pull the phosphor plate  3  onto the support  40  in a simple manner adapted to the respective format. 
   The support  40  is also inclined by an inclination angle α in relation to the vertical. 
   If the phosphor plate  3  has arrived at the region of the support  40 , the plate, due to its own weight, can lie on the support  40  or the extended spacers  41  without additional guiding or pressing elements being required. The spacers  41  can now be retracted into the support  40  and the phosphor plate  3  moves closer to the support  40  due to its own weight, and is finally additionally pulled onto the support  40  by turning on the vacuum at the corresponding suction nozzles  44  of the individual segments  42 . 
   This state is illustrated in  FIGS. 2   a  and  2   b . In this example of an embodiment, the conveyance device  15  is configured in such a way that it furthermore holds the phosphor plate  3  with its grasping arms  16  while the plate already lies securely on the support  40 . In this way a particularly secure hold of the phosphor plate  3  on the support  40  is guaranteed. Moreover, in this way a new grasping process can be omitted before starting to convey the phosphor plate  3  back into the cassette  2 . 
   When the phosphor plate  3  lies securely on the support  40 , a read-out device  50  moves upwards out of its original parking position (see  FIGS. 1   a  and  1   b ) beneath the lower end of the support  40  in direction S onto the phosphor plate  3 . At the same time, by a corresponding spacing mechanism (not shown), a corresponding distance between the read-out device  50  and the support  40  is set, the distance set being dependent upon the overall thickness of the phosphor plate  3  read out from the electronic storage unit  10 . 
   The read-out device  50  can now read out, line for line, the X-ray information stored in the phosphor plate  3  while it moves in the direction S over the phosphor plate  3 . The read-out device  50  is preferably a so-called line scanner with which a whole line of the phosphor plate  3  is respectively stimulated with stimulation light, and the emission light thus produced is collected by a linear, locally releasing detector. This type of line scanner is described in greater detail for example in the German disclosure document DE 197 52 925 herein incorporated by reference in its entirety for background information only. 
   Following the read-out from the phosphor plate  3 , the distance of the read-out device  50  from the support  40  is increased again, and the read-out device  50  travels back to its original parking position at the lower end of the support  40 . The phosphor plate  3  is released from the support  40  when air is let into or pumped into the respective suction nozzles  44  of the individual segments  42 . 
   Before starting the return conveyance, the spacers  41  are extended out of the support  40  again. The phosphor plate  3  can now be conveyed back into the cassette  2  by the conveyance device  15 . 
   While being conveyed back, any remaining X-ray information in the phosphor plate  3  is deleted by a deletion lamp  19  located in the region beneath the cassette holding slot  4 . 
   Between the support  40  and the cassette holding slot  4  guide elements are provided which, in particular during the return conveyance, ensure that the phosphor plate  3  is reliably guided. Due to its own weight, the phosphor plate  3  here lies against the guide elements which in the example shown are in the form of guiding skids  17  and guide rolls  18 . 
   When the phosphor plate  3  is fully inserted in the cassette  2  once again, it can once again be locked into the cassette with the locking mechanism already described above. The grasping arms  16  of the conveyance device  15  now let go of the phosphor plate  3 , and the conveyance device  15  travels back to its parking position. The cassette  2  is now closed by shutting the flap described above, the sealing lips  13  (see  FIG. 4 ) are moved back from the wide sides  14  of the cassette  2 , and the fixing element  20  releases the cassette  2  along with the closure mechanism  21  located on the same, and the cassette can now be removed again from the cassette holding slot  4  by a user. 
   Preferably, a coupling device  35 —only shown in a highly schematised form in  FIGS. 1   b  and  2   b —is provided which can mechanically couple the cassette holding slot  4  with the support  40  during the conveyance of the phosphor plate  3  (see  FIG. 1   b ) and mechanically uncouple it while the storage phosphor plate  3  is being read out. For simplification, the mechanical uncoupling is symbolised by the dotted line of the coupling device  35  in  FIG. 2   b.    
   In this way, on the one hand, particularly secure conveyance of the phosphor plate  3  from the cassette to the support  40  is guaranteed because the cassette  2  located within the cassette holding slot  4  and the support  40  can not move relative to one another due to the mechanical coupling. 
   By the mechanical uncoupling of the support  40  being suspended movably, for instance by elastic elements, in the housing of the device  1 , it is also possible for vibrations of the housing, in particular due to external impacts or shaking not, or only to a small extent, to be transferred to the support  40 . In this way, a particularly secure and reliable read-out of the phosphor plate  3  is guaranteed. 
   In an alternative embodiment of the device shown in  FIGS. 1 and 2 , the phosphor plate  3  is read out while this is being conveyed by the conveyance device  15  and  16  on a conveyance level inclined in relation to the vertical. The read-out device  50  is arranged in such a way (not shown) that the phosphor plate  3  is conveyed past the read-out device  50  and can thus be read out by the same while the phosphor plate  3  is conveyed downwards away from the cassette  2  or upwards towards the cassette  2 . The read-out device  50  can be located near to the deletion device  19  shown in  FIGS. 1 and 2  so that the phosphor plate  3  can be read out when it is removed from the cassette  2 , and deleted when it is conveyed back into the cassette  2 . 
   In  FIGS. 8   a ,  8   b  and  8   c , an alternative embodiment of the device according to the invention is respectively shown in a side view. The fixing of the cassette  2  in the cassette holding slot  4  and the removal of the phosphor plate  3  from the cassette  2  by the conveyance device  15  happen according to the above embodiments in connection with  FIGS. 1 to 6 . 
   Unlike the examples of embodiments described above, the support  60  on which the phosphor plate  3  is located during the read-out is not securely fastened, but is conveyed past the securely fastened read-out device  51  by a suitable drive device. In the examples shown, the drive device includes a cable or strap winch  61  which is attached to the support  60 , is turned round by a pulley  62 , and driven by a drive roll  63 . 
   At the point in time illustrated in  FIG. 8   a , the phosphor plate  3  lies flat on the support  60  which is inclined by an inclination angle α in relation to the vertical. In order to guarantee a secure hold and positioning of the phosphor plate  3  on the support  60  during read-out, the support  60  is provided with appropriate attracting devices, such as suction nozzles (as in  FIG. 7 ) or suction cups, or holding devices. Furthermore, the conveyance device  15 , with which the phosphor plate  3  is removed from the cassette  2  and conveyed to the support  60 , is also engaged with the phosphor plate  3  by means of which the latter is additionally held. 
   By rotating the drive roll  63 , the phosphor plate  3 , together with the support  60 , can now be lowered in direction S 1 . A point of time during the lowering is shown in  FIG. 8   b . Here, the phosphor plate  3  is moved in direction S 1  past the securely fastened read-out device  51  and can be read out by the same. 
   The read-out device  51 , as in the case of the read-out device  50  ( FIGS. 1 and 2 ) can be a so-called line scanner. Preferably, the read-out device  51  is in the form of a so-called flying spot scanner with which a laser beam deflected by a rotating mirror stimulates the storage phosphor plate point by point, and the emission light respectively stimulated by a photomultiplier is collected. 
   In an alternative embodiment, the phosphor plate  3  can only be read out on its way back, as it is moved past the read-out device  51  in direction S 2  (see  FIG. 8   c ). Dependent upon the design of the drive device  61  to  63 , in particular of the drive used for the drive roll  63 , in this way, the phosphor plate  3  can be particularly reliably conveyed past the read-out device  51  with very few fluctuations. 
   Independent of the respective movement direction S 1  or S 2 , the phosphor plate  3  is inclined by inclination angle α in relation to the vertical during read-out. 
   After the read-out, the phosphor plate  3  has returned to the position shown in  FIG. 8   a , and can—similar to the examples in FIGS.  1  and  2 —be conveyed back by the conveyance device  15  into the cassette  2 . Any information remaining in the phosphor plate  3  is deleted here by turning on the deletion lamp  19 . 
   The drive device described in  FIGS. 8   a ,  8   b  and  8   c  can also be replaced by other suitable drive devices. For example, the support  60  from a so-called spindle drive (not shown) can be moved on a level inclined in relation to the vertical. Here, the support  60  is set in motion by one or more rotating shafts or spindles, arranged parallel to the support  60 , driven by a motor.