Device for reading out information stored in a memory layer and X-ray cassette and X-ray table

The present invention relates to a device for reading out in a Storage layer information stored in accordance with the preambles of Claims 1 and 3 and an X-ray cassette and an X-ray table.

In particular for medical purposes is from an object, for example, a patient by means of an X-ray generates an image in a Storage layer is stored as a latent image. As a storage layer it mostly uses a phosphor layer. For reading out the memory in the layer stored X-ray image, the storage layer excited by a radiation source. It emits then due to this Excitation light, an intensity corresponding to the stored X-ray image having. The light emitted by the storage layer, light from receive a reception means and then converted into electrical signals, so that the stored in the storage layer X-ray image can subsequently be made visible. The X-ray image can For example, displayed directly on a monitor or on a specially for radiographs usable photographic X-ray film to be written.

An apparatus for reading out information stored in a storage layer Information is known from the patent application WO 99/28765. At this known device is the storage layer line by an excitation radiation stimulated, which is generated by a radiation source. The Radiation source may be, for example, a laser diode line. The result the excitation of the memory layer emitted light is of a receiving means receive. For this purpose, this receiving means comprises a plurality of photosensitive on surfaces which are arranged in a line next to each other are. The radiation emitted by the storage layer radiation is photosensitive by receiving surfaces. The receiving means may be a Charge-Coupled Device (CCD) be that a plurality of row-wise juxtaposed photodetectors contains. To read the in the Storage layer stored information is the radiation source and the receiving means by means of a linear motor driven over the memory layer.

Starting from the patent application WO 99/28765, the present invention the object of a simple and effective way playback of stored information to improve quality.

This object is according to the teachings of claims 1, 3, 9 or 10 dissolved.

Due to the invention may advantageously be an impact of a high-energy Abspeicherstrahlung be avoided on the reading means. The reading means includes semiconductor devices, against the high-energy Abspeicherstrahlung are sensitive. Due to the invention it is advantageously possible a formation of lattice defects within these semiconductor devices to prevent or at least reduce. Such lattice defects can the specific characteristics of the semiconductor devices with change increasing irradiation frequency by means of Abspeicherstrahlung. It can aging of the semiconductor devices occur, turn to a loss of image quality when playing back the stored can cause information. The signal-to-noise ratio in the Play the stored information is deteriorated. this will avoided because of the invention.

In an advantageous embodiment of the invention, the shielding means, with the reading means is shielded against the Abspeicherstrahlung to a to prevent impingement of the Abschirmstrahlung to the reading means, lead. Thereby can be a simple and effective way, especially one as Abspeicherstrahlung X-rays used to shield.

In a further advantageous embodiment of the invention by means of the invention Conversion means for converting the Abspeicherstrahlung in radiation which is reduced with respect to their energy content, a wavelength conversion performed. This allows, for example, an X-ray be transformed into a wavelength range which is in the visible part the spectrum is, especially in the blue or ultraviolet Reported of the spectrum.

In another, particularly advantageous embodiment of the invention, is the Shielding or the conversion means on a rest position for the reading means arranged. This allows the size of the shielding or conversion means be limited. Furthermore, the shielding or conversion means within the apparatus of the invention associated with a fixed location. It is therefore ensures that the reading means in the storage of information in the storage layer before the high-energy radiation shield is protected.

Advantageously, in the by shielding or conversion means protected reading means also comprises a radiation source for exciting the storage layer contain. This radiation source is therefore simultaneously with the Receiving means protected from the Abspeicherstrahlung.

Further advantageous embodiments are disclosed in the dependent claims.

In the following the invention and its advantages with reference to embodiments to be and the drawings.

Show it:<dl tsize="6"><dt>Fig. 1</dt><dd>an embodiment of an X-ray cassette according to the invention,</dd><dt>FIG. 2</dt><dd>a more detailed schematic view of the embodiment of X-ray cassette during reading of stored information,</dd><dt>Fig. 3</dt><dd>a further schematic view of the embodiment of the X-ray cassette while recording an X-ray image,</dd><dt>Fig. 4</dt><dd>a detailed, schematic view of another embodiment the X-ray cassette according to the invention with a conversion means during irradiation with X-rays and </dd><dt>Fig. 5</dt><dd>an embodiment of an X-ray table according to the invention with an X-ray cassette.</dd></dl>

The following are used for identical or functionally identical elements have the same reference numerals used.

Fig. 1 shows an embodiment of an X-ray cassette according to the invention 1. This X-ray cassette 1 contains a storage layer 15. The storage layer 15 is a phosphor plate here. In the phosphor plate 15 X-ray images can be saved. To read the in Phosophorplatte 15 stored X-ray images includes the X-ray cassette 1 a read head 10. The read head 10 is by means of a drive 27 along two Guide rods in a feed direction A over the surface of the phosphor plate 15 transportable. The drive 27 may, for example, a linear motor be. Behind the read head 10 an erase lamp 19 is attached. The Erase lamp 19 is connected to the read head 10, and may - as well as the Read head 10 - by means of the drive 27 over the surface of the phosphor plate 15 transported in the feed direction A. The erase lamp 19 is used for erasing data stored in the phosphor plate 15 information after reading of an X-ray image by the read head 10 further are stored in the phosphor plate 15th The erase lamp 19 and the Read head 10 extend in a row direction B over the entire width of the Phosphor plate 15. The row direction B perpendicular to the direction A.

The X-ray cassette 1 further includes a control means 13 with which the in the components X-ray cassette 1 contained are driven. The read head 10, the erase lamp 19 and the control means 13 are within the x-ray cassette 1 of FIG. 1 located to the right of the phosphor plate 15. Read head 10, erase lamp 19 and control means 13 are in a rest position 26. In this rest position 26, the read head 10 and which are Erase lamp 19 is not by means of the drive 27 over the surface of the phosphor plate 15 down. About the rest position 26, shielding means 22 is arranged. The shielding means 22 is here in this embodiment, Lead shielding. Reading head 10, erase lamp 19 and the control means 13 are directed by the lead cover 22 against the X-ray cassette 1 X-rays protected. Such X-rays of the lead cover 22 do not pass. The lead cover 22 is connected to the top (Cover) of the housing of the X-ray cassette 1 securely connected. That `s how it is possible, the lead cover 22 is not connected to the housing of the X-ray cassette 1 to connect, but the lead cover 22 on the transportable unit Read head 10, erase lamp 19 and control means to secure. 13 The control means 13 may be fixedly mounted in the X-ray cassette. 1 It's not necessary, the control means 13 with which the by the drive 27 over the surface Phosphor plate 15 transportable read head 10 and the erasing lamp carry 19th Through appropriate wiring between the control means 13 on the one hand and the reading head 10 and the erase lamp 19 on the other hand, is a Control of the read head 10 and the erase lamp 19 may also be possible if carried out a readout of the information stored in the phosphor plate 15 information.

Instead of lead cover 22, other materials for shielding the reading head 10, the erase lamp 19 and the control means 13 is inserted will. It is possible to provide a conversion means instead of the shielding means 22, with the high-energy Abspeicherstrahlung (X-rays) with respect their energy is reduced.

FIG. 2 shows a more detailed view of the X-ray cassette 1 according to FIG. 1. It is the read head 10 is shown, which includes a radiation source eleventh These Radiation source 11 is here a line of laser diodes having a plurality of side by side laser diodes arranged. Mittes the laser diode line 11 is a Excitation radiation 16 generated which to excite the phosphor plate 15 serves. In this embodiment, the phosphor plate 15 is line by line excited. Due to the excitation by the excitation radiation 16 emitting phosphor plate 15 an emission radiation 17. This is of an optical imaging means 14, for example, contain micro-lenses can imaged on a CCD line 12th The CCD array 12 comprises a plurality of juxtaposed photosensitive surfaces 18. In this Example, an image of the information stored in a line of the phosphor plate 15 detected Informtionen of the CCD line 12 and converted into electrical signals will. These signals generated by the CCD array 12 are transferred to the control means 13 forwarded to that end with the reading means 10 and in particular is connected to the CCD-line 12th

In the example of FIG. 2, the read head 10 is driven by the drive 27, to read out the information stored in the phosphor plate 15 information. The read head 10 is in the example of FIG. 2 is not in its rest position 26. Rather, the reading head 10 is here beside the rest position 26, which in turn is covered by lead shielding 22nd When reading out the information stored in the phosphor plate 15 information found simultaneous Abspeichem of new information in the phosphor plate 15 does not occur.

Fig. 3 shows another example of the X-ray cassette according to the invention. at This example shows information stored in the phosphor plate 15th For this purpose, of an X-ray source (not shown) is a X-rays 25 is output in the direction of X-ray cassette. These X-ray radiation 25 strikes in substantially the entire extent of the X-ray cassette 1. In the example of FIG. 3 is the function of the lead cover 22 clearly. The incident on lead shielding 22 X-rays 25 is screened off and can not be on the read head 10 and the Control means 13 meet. The contained in the read head 10 and the Steuermittel13 Components are not supported by the high-energy X-rays 25 irradiated.

Fig. 4 shows a further embodiment of the X-ray cassette according to the invention 1. Instead of the lead cover 22 the X-ray cassette 1 includes here Conversion means 29. This conversion means 29 converts the X-rays 25 in a conversion radiation 28. The radiation conversion 28 has a Energy, which is much lower than that of the X-rays 25. The Conversion means 29, for example, a so-called scintillation layer be as it is 195 05 729 C1 known from the patent DE. By a Such scintillation layer 29, the wavelength of the excitation radiation 25 be transformed. The wavelength of the radiation conversion 28 is here because of processing performed by the conversion means 29 wavelength conversion approximately in the blue or ultraviolet region of the spectrum.

Fig. 5 shows an embodiment of an X-ray table according to the invention 20, in which the X-ray cassette 1 described above is used. Of the X-ray table 20 includes a Röntgenfuß 23, in which the X-ray cassette 1 is located, and means disposed on the support surface 23 Röntgenfuß 24th Patients are placed on the radiograph In this bearing surface 24th about the bearing surface 24 and the Röntgenfuß 23 with the X-ray cassette therein 1 is mounted on the X table 20 is an X-ray source 21st The X-ray source 21 emits for receiving the X-ray image in the Phosphor plate the X-rays 25 towards the support surface 24th