Radiant energy – Source with recording detector – Using a stimulable phosphor
Reexamination Certificate
2000-05-11
2001-10-30
Kim, Robert H. (Department: 2878)
Radiant energy
Source with recording detector
Using a stimulable phosphor
C250S584000, C250S586000
Reexamination Certificate
active
06310357
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a method for reading out a storage luminophore plate, of the type used to store an image produced in a medical x-ray system.
2. Description of the Prior Art
The scanning of storage luminophore plates with a stimulation laser is known. The area employed for imaging is thereby scanned point-by-point along lines. The speed of this scanning is limited by the minimum integration time required for each picture element, this integration time being prescribed by the decay time of the storage luminophore. The readout time for the entire image format given current devices amounts to 1-2 minutes and is actually too slow for modern hospital operation. Moreover, such a device for line-by-line punctiform scanning with a mechanically guided laser beam, and readout with a photo multiplier has a large structure. Due to its large structure, this device cannot be integrated into a medical X-ray system but must be erected separately therefrom, which requires space and room. The physical transport of the storage luminophore plate with corresponding time delay and risks of mix-ups, etc., between the actual X-ray exposure and the digitization on the basis of the readout of the storage luminophore plate with the device and the transmission of the data are disadvantages associated with this type of device.
German OS 195 06 798 discloses an alternative to the aforementioned scanner device. German OS 195 06 798 discloses a device for reading out storage luminophore plates wherein a contact pressure means for a storage luminophore film is provided and with which the storage luminophore film can be pressed planarly against a counter-plate and fixed. An aSi:H detector matrix is arranged at the opposite side of the counter-plate. This detector matrix and the storage luminophore film thus can be aligned in substantially parallel planes relative to one another via the contact pressure device.
A detector matrix as disclosed in German OS 195 06 798 is expensive to manufacture and, due to the multitude of detector elements, the risk of an outage of individual detector elements is relatively high, which degrades the signal output.
U.S. Pat. No. 4,694,163 discloses a device for readout of a storage luminophore plate with which the storage luminophore plate can be subjected to a sag. This device has a roller that can be adjusted from a first position, in which it has no contact with the storage luminophore plate, into a second position in which it effects a sag of the storage luminophore plate. A good and constant guidance of the storage luminophore plate is to be assured due to the sag of the storage luminophore plate.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a device for the readout of a storage luminophore plate which, with a compact and economic structure, enables a fast readout of the storage luminophore plate.
The above object is achieved in accordance with the principles of the present invention in a device for reading out a storage luminophore plate having a holder for the storage luminophore plate as well as for a detector line, and a device for setting a spacing between the storage luminophore plate and the detector line, wherein the spacing is controlled or regulated so as to be substantially constant relative to the storage luminophore plate, at least within the region of the detector line.
The above object is also achieved in accordance with the principles of the present invention in a device wherein the storage luminophore plate exhibits a sag at a central region thereof, and wherein the detector line is flexible, and wherein the device for maintaining a substantially constant spacing between the storage luminophore plate and the detector line deforms the detector line so as to conform to the sag of the storage luminophore plate, thereby controlling or regulating the spacing so as to be substantially constant, at least within the region of the detector line.
An advantage of the invention is that only one detector line is employed, so that the detector is economic and the relative risk of outage of detector elements is low. Because the spacing between the detector line and the storage luminophore plate is substantially the same over the area of the detector line, the modulation transfer function does not vary in a location-dependent manner along the detector line. Measured signals that are uninfluenced by location thus can be derived from the detector line, these being able to be further-processed into easily diagnosed image signals. Since only one line-shaped detector line is employed in the subject matter of the invention, the device is compact in structure and can also be integrated in an X-ray diagnostics apparatus, if desired. The readout time is reduced compared to the line-by-line punctiform scanning since the signals of a line can, preferably, be simultaneously read out.
It is advantageous for the detector line to be flexibly fashioned and for the detector line to be caused to sag in a manner to a sag of the storage luminophore plate. The modulation transfer function thus is not disadvantageously influenced by an unequal spacing from the detector line caused by the sag of the storage luminophore plate.
Since the storage luminophore plate exhibits the largest sag in the region of its center axis, it is advantageous when the device for effecting the sag acts in the middle region of the detector line, so that this also exhibits the largest sag in that region and the modulation transfer function is not disadvantageously influenced.
A device that engages at least one edge of the detector line for effecting the sag has an equivalent effect.
Alternatively, the device can engage an opposite edge of the detector line for effecting the sag.
It has proven advantageous to employ piezoelements for effecting the sag. These piezoelement elements are inexpensive and require only a slight space in order to effect a sag of the detector line. Alternatively, at least one electromechanical element can also be employed.
The drive of the device for effecting the sag is preferably dependent on the x/y coordinates of the detector line with reference to the storage luminophore plate since the sag is not constant over the entire area of the storage luminophore plate.
In an embodiment of the invention, the detector elements of the detector line can be adjustable in terms of the spacing from the storage luminophore plate. The spacing between the detector elements and the storage luminophore plate is best maintained when the detector elements are individually adjustable in terms of the spacing. Due to the many adjustment devices and their drive, however, this embodiment is very complicated. It is therefore advantageous to arrange the detector elements in groups that are adjustable with respect to the spacing from the storage luminophore plate because fewer adjustment device are required. Matching to the sag of the storage luminophore plate, however, is then not as good.
REFERENCES:
patent: 4587036 (1986-05-01), Degenhardt
patent: 4694163 (1987-09-01), Ohgoda et al.
patent: 4742225 (1988-05-01), Chan
patent: 5724121 (1998-03-01), McKinley et al.
patent: OS 38 03 766 (1989-08-01), None
patent: OS 195 06 798 (1996-08-01), None
patent: OS 197 52 925 (1999-06-01), None
patent: 0 142 865 (1985-05-01), None
patent: 0 859 244 (1998-08-01), None
Fuchs Manfred
Hell Erich
Mattern Detlef
Kim Robert H.
Schiff & Hardin & Waite
Siemens Aktiengesellschaft
Song Hoon Koo
LandOfFree
Device for reading out a storage luminophore plate does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for reading out a storage luminophore plate, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for reading out a storage luminophore plate will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2550572