BACKGROUND OF THE INVENTION Field of the Invention The subject invention relates generally to digital medical imaging systems and is specifically directed to a system for converting an installed, conventional film-based analog x-ray system into a digital imaging apparatus on site and with a minimum of modification to the existing equipment.

Discussion of the Prior Art.

X-ray systems are well known in the medical field and are routinely used as a diagnostic tool.

Typical systems include a surface for supporting and immobilizing the patient or the body part to be imaged, an x-ray head for directing x-rays to and through the body, and an image capture device on the opposite of the body to receive the emitted, attenuated x-rays. In historic systems, the image capture device is a chemical film substrate and an intensifying screen which may be used in combination with an optional grid, wherein the film and screen reacts to the emitted x-rays to form an image. The support surface of the body usually includes a"window"under which the film/screen system is placed for exposure. Typically, the film and screen is mounted in a carrier known throughout the industry as a film cassette. Where desired, the grid is placed in an overlying relationship with the film and screen, between the cassette and the x-ray head. The film cassette is positioned in a film bucky that is mounted in place in communication with the window where the x-ray image is captured. The film cassette is then removed from the bucky and is physically transported to a developing unit. Next, the film is chemically developed to provide an x-ray transparency which may be used for diagnostic purposes. The traditional systems use a silver halide- based film to capture and display patterns of x-rays that have been attenuated during passage through the object to be analyzed, and with the attenuated exposure have then developed, utilizing a chemical developing process. While such systems provide very satisfactory x-ray images, the developing system is both expensive and time-consuming. Moreover, each developed film image exists as a single image, which cannot be readily duplicated or archived without duplication of the development process.

More recently, certain types of x-ray images have been captured by a digital capture device, wherein the emitted x-rays are collected on an electronic collector plate or array and a complex digital signal is produced comprising the x-ray image. The digital signal is then processed and reproduced on a print media, or on an electronic display such as a CRT. CAT scan systems are an example of such a digital x-ray device. While the more sophisticated systems such as CAT scan systems and the like have utilized digital image capture since their inception, the standard or conventional general practice and emergency x-ray systems have continued to be almost exclusively chemical film imaging to the present day.

Digital array image capture devices have been recently disclosed, where the intent is to permit the digital capture of conventional x-ray images. An example of such a device is shown and described in U. S. Patent No. 5,381,014, entitled:"Large Area X-ray Imager and Method of Fabrication,"issued to L. S. Jeromin et al on January 10,1995, which describes a large area x-ray image capture device comprising a plurality of juxtaposed, discrete array modules in an assembly carried on a base plate. Each module is disposed adjacent to at least one other module to form a two- dimensional mosaic of modules. Each of the discrete modules includes a plurality of thin-form transistors arrayed adjacent the top surface of a dielectric substrate wherein at least one precision- ground edge forms a precise abutment with a precision-ground edge of another substrate. A continuous radiation detecting layer is disposed over the plurality of juxtaposed modules, and it produces a latent radiographic image in the form of electrical charges. Such a method minimizes or totally voids the non-radiation-detecting areas created at the borders between array modules.

The ability to manufacture a large area digital array such as that shown and described in the aforementioned patent has made it possible to construct conventional chest and table X-ray systems using digital image capture devices in lieu of the historic silver halide-based film systems. There are many advantages to such a system in addition to the elimination of the use of the chemically developed film and the developing steps in the process. Once the image is captured in a digitized format, it may be processed as any other digital signal, permitting electronic archiving, transmission of the image to remote workstations and reproduction of multiple copies at multiple workstations or as hard print copies. Such systems have greatly enhanced the record keeping capability that many health care systems now use, permitting attachment of the image directly to a patient's electronically stored records, for example. While such systems are highly desirable because of these and other advantages relating to the ability to process, manipulate and store digital data in general, the health

care industry faces almost prohibitive expenses in shifting from chemical film conventional X-ray to digital systems. As these systems have been developed to date, the entire conventional x-ray image capture and developing system is scrapped and replaced by new digital imaging equipment.

Therefore, the incorporation of this technology has been hampered by cost constraints, even though the advantages of digital imaging techniques has been widely recognized and accepted.

Therefore, there is a need for a digital imaging system for conventional x-ray which is more sensitive to the costs issues facing the medical imaging field.

SUMMARY OF THE INVENTION The subject invention is a self-contained digital imaging array adapted to be fit in a bucky carrier mounted under the table or other patient support surface of a typical x-ray unit. This permits conventional film-based analog image capture systems of the prior art to be upgraded to full electronic capability for capturing diagnostic images in digital format, integrating those images with patient demographics, text reports, lab results and other information, and archiving and displaying that information on monitors or hard copy prints. The system of the subject invention permits conversion of the historic film-based analog systems electronic, fully integrated systems at a fraction of the costs of full replacement systems now available in the marketplace.

The medical imaging technology requirements are undergoing dramatic change. Previously, the various aspects of the medical record keeping process were operated as separate components of the industry, with hard copy records of diagnostic images, text notes, patient demographics and other information being merged into a single file by use of hard copies. Over the past several years, the health care industry has moved toward fully integrated systems where much of the information is on-line and available from a single central processing unit via a plurality of both comprehensive and special purpose work stations. More and more health care systems are incorporating the ability to merge imaging, text and demographic material into single, electronic files which may be transmitted, read and stored via electronic transmission means. Not only does this permit ready access of the information at any location having a compatible workstation, but the transmission process itself is greatly enhanced by minimizing the reliance on producing and transmitting hard copies to each required location. The diagnostic capabilities are also greatly enhanced since the information may be transmitted to off-site locations where personnel with special expertise can review information on a near real-time basis. Further, such systems permit transmission of critical information to a

central location from any remote location in the world through computer/satellite uplink, microwave or hardwired systems.

Conventional film-based analog chest and table x-ray systems have been among the last aspects of imaging technology to convert to fully digital imaging techniques. This is primarily because of the large base of installed systems coupled with the costs associated with conversion.

The present invention provides an attractive solution to the conversion process by permitting a substantial portion of the existing equipment to remain functional. In its simplest form, the subject invention can be defined as a self-contained cartridge or module designed to replace the film cassette and film bucky conventionally associated with the standard chest and table x-ray systems. With minor modification to the existing table and support frames, the film is replaced with the digital imaging module and the rest of the system operates in the conventional manner. However, instead of the x-ray being directed toward a film substrate, it is directed toward the digital imaging array, and the resulting digital image signal is then processed and transmitted to the integrated digital system.

In its preferred form, the retrofit system of the subject invention contains an electronic imaging module housed in a series of nested drawers, making orientation and rotation possible without removing the module once installed. One significant advantage of the subject invention is the ability to use the same module for both standard in-table exams and extremity exams. Another significant advantage of the system is the ability for lateral and oblique views without moving the patient.

In order to convert a conventional system from film-based analog technology to digital imaging technology, the film bucky for supporting the film cassette is first removed from the system. A new carriage is installed to accommodate a digital imaging bucky which contains the imaging array module. The digital imaging array module is adapted to be slidably received in the new bucky for orientation with the window or zone provided in the existing system, whereby x-ray images may be transmitted in the same manner as with conventional film. The digital imaging module is then coupled via a hardwired system or cable to conventional digital signal processing equipment, whereby the image signal is captured and transmitted into the digital information system of the facility.

The carriage positions the digital imaging bucky and moves and positions the array relative to the table or support surface and the x-ray head. The bucky houses the array, the exposure control,

the optional grid and related components. In the preferred embodiment of the invention, the array may be rotated a full 90°, permitting both portrait and landscape imaging. In addition, the array may be extended from the carriage and table or support surface, permitting easy capture of extremity views with a minimum of discomfort to the patient.

In the best mode of the invention, the retrofit installation requires the height of the table or support surface to be raised approximately one inch in order to accommodate the difference in the thickness of the digital array module versus conventional analog film. The bucky (which houses the array module), the carriage, and the adapter kit for installing the carriage and bucky into the conventional system can be installed in a conventional system economically, with virtually no modification of the remaining components of the conventional system. The cost of the retrofit system is substantially less than the costs of full replacement of the conventional system with a fully self-contained digital system.

It is therefore, an object and feature of the subject invention to provide a self-contained x-ray bucky with a digital imaging array module for installation and use in conventional chest and table x-ray systems.

It is an additional object and feature of the subject invention to provide an apparatus for retrofitting conventional film-based x-ray systems with a digital imaging system.

It is another object and feature of the subject invention to provide a digital imaging array for table and chest x-ray systems which may be rotated for orientation to provide both portrait and landscape imaging.

It is yet another object and feature of the subject invention to provide a table and/or chest x- ray system wherein the imaging module may be extended in order to accommodate extremity views.

Other objects and features of the invention will be apparent from the accompanying drawings and detailed description of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side view of a typical table x-ray unit readied for installation of the retrofit system of the subject invention with the film carriage and bucky shown in phantom.

Fig. 2 is an exploded view of the table, support rail system, bucky and support base shown in Fig. 1.

Fig. 3 is a sectional view, taken along line 3-3 of Fig. 1.

Fig. 4 is a fragmentary, perspective view showing the carriage of the subject invention, mounted in the table of Fig. 1, with a digital array bucky installed therein.

Fig. 5 is a view looking in the same direction as Fig. 4, with the bucky drawer extended and the digital array in a partially rotated position.

Fig. 6 and 6A are views similar to Fig. 5, with the bucky in the landscape position, for extremity imaging.

Fig. 7 shows the table and bucky with the slidable grid in place over the extended bucky.

Fig. 8 is a diagrammatic view showing the bucky in the position of Figs. 1 and 3, with the array rotated for portrait imaging.

Fig. 9 is a diagrammatic view similar to Fig. 8, with the array rotated for landscape imaging.

Fig. 10 is a diagrammatic view, showing the bucky extended, with the array rotated for portrait imaging.

Fig. 11 is a diagrammatic view similar to Fig. 10, showing the array rotated for landscape extremity imaging.

Fig. 12 is a diagrammatic view showing the extended bucky vertically tilted on a horizontal table in a cross table configuration, with the array rotated for portrait imaging.

Fig. 13 is a diagrammatic view similar to Fig. 12, with the extended, tilted array rotated for landscape imaging.

Fig. 14 is a diagrammatic view showing the table in a vertical tilt position, with an extended bucky and the array rotated for landscape imaging.

Fig. 15 is a diagrammatic view similar to Fig. 14, with the extended bucky on the tilted table rotated for portrait imaging.

Fig. 16 is a section view taken along line 16-16 of Fig. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A typical x-ray table system is shown in Figs. 1, 2 and 3. The table top 4 is supported on a pair of parallel rails 10 which are supported above the floor at a suitable height by a standard base 22. An x-ray head vertical support 23 may also be mounted on the base 22. A head support arm 24 is extended. The x-ray head hanger 21 is mounted on the outer end of the arm 24 for supporting the x-ray tube and x-ray head 2. The sidewall 5 includes a bucky slot 6 wherein the bucky 25 is inserted.

As is typical, table top rails 11 are secured to the subtop 5 outboard of the table top 4. In the embodiment shown, the system includes a chain drive tilt motor 19 with a standard chain, gear and

tilt assembly 20, high tension cable system 18 and counterweights 13, whereby the table may be tilted to accommodate placement of the patient on the unit for certain images. In the configuration shown, the table may be tilted from the horizontal position (parallel to the floor such that a patient may lay on the table top) to a maximum tilt of 90 degrees (perpendicular to the floor or vertical such that a patient may stand in front of the array).

As better shown in Fig. 2, the table is supported on a pair of parallel, longitudinal table rails 10 which are supported by the base or stand 22. Typically, the table rests directly on a roller system lOa, which is adapted to roll on the rails 10, whereby the table may be selectively moved along the translation axis as indicated by the arrow"A". Bucky rails 8 are mounted longitudinally between the opposite ends of the stand 22 and beneath the table rails 10. The bucky rails are fixedly mounted for supporting the bucky in a pre-selected position relative to the table. In the retrofit application of the subject invention, the bucky carriage drawer 26 is mounted on the bucky rails 8 by a plurality of brackets 9, and is positioned above the rails 8, between the rails 8 and the table top 4. Since the array module 46 (see Fig. 5) is generally larger in height than a typical film cassette, there may not be sufficient clearance between the table rails 10 and the bucky rails 8 to accommodate a retrofit installation. In such applications where additional clearance is required, the table rails 10 are raised by placing spacers 47 between the rails and the base 22, as shown in Fig. 2. This permits the digital array module of the subject invention to be incorporated in the prior art installed analog system with a minimum of modification to the installed unit.

As shown in Figs. 3,4 and 5, the carriage 26 for the bucky module is mounted directly on the rails 8 by a plurality of supports 9, with the carriage in alignment with the slot 6, and the bucky unit 25 housed in the carriage 26 in alignment with the slot 6 in the table subtop 5. As better shown in Fig. 16, the bucky carriage 26, bucky 25 and digital array 46 form a series of nested drawers which fit in the slot 6 of the table unit (designed to hold the film cassette and film bucky of the prior art), permitting retrofit of in service systems to a fully digital mode.

The digital bucky 25 is slidably mounted in the carriage 26 and has a drawer front 28 surrounding and covering the slot 6 when fully installed and retracted in the carriage. A handle 30 is provided for grasping and sliding the bucky/drawer unit in and out of the slot 6. In the preferred embodiment, the entire carriage/bucky assembly is 4-1/4 inches thick (depth), 30 inches wide (along longitudinal axis of table) and 23 inches deep (orthogonal to the longitudinal axis), and will readily fit in the available space in typical table systems, with the exception that the table top 4 may be

raised on the rails 10 by spacers 47 (as best shown in Fig. 2). In order to assure that the array stays within operating temperature constraints, a cooling fan 21 (see Fig. 1) may be mounted in the base 22 of the table. The system permits both landscape and portrait imaging in the table, extended and tilted modes, as well as both landscape and portrait configurations in the cross table mode.

A perspective view of the bucky/carriage assembly, with tabletop 4 and rails 10 shown in phantom, is illustrated in Fig. 4. In the preferred embodiment, and as shown in Figs. 4 and 7, the carriage 26 is a hollow box with an open top, bottom 34 (Fig. 16) and closed side walls 36, 37, 38, with one open end wall for accommodating the bucky drawer 25 (Fig. 7). The support brackets 9 are secured to the sidewalls 36,37 and directly to the rails 8 (see Figs. 2 and 3) for mounting the bucky/carriage assembly in the table unit. As best shown in Figs. 6,7 and 16, the bucky carriage 26 includes elongated, parallel guides 60. The bucky drawer 26 includes mated slides 62 which are supported by the guides 60 in order to facilitate sliding movement of the bucky drawer 25 and the array 46 in and out of the carriage 25 and the slot 6.

As shown in Figs. 6 and 7, the upper rail 64 of the slide assembly 62 defines a guide for receiving slide channels 66 in the grid 48. The grid 48 is slidably mounted on the guides 64 and can be extended and retracted relative to the bucky drawer 25 when the bucky drawer is in the extended position as shown in Figs. 6 and 7. When the grid is retracted as in Fig. 6, the array 46 is exposed and may be rotated between the landscape and portrait positions as shown in Fig. 5. The grid 48 is then extended as in Fig. 7 to cover the array 46, in the normal fashion. A palm pad 54 is provided to accommodate sliding. Typically, and as is well known in the art, the slides will have positive stops to assure that the bucky 25 extends only a predetermined distance out of the carriage 26.

As is best shown in Fig. 5, the digital array module 46 is mounted on the base or bottom wall of the bucky 25. In the preferred embodiment, the digital array module is mounted on a turntable so that it can be rotated ninety degrees to accommodate different view configurations as more clearly illustrated in Figs. 8-15. As will be understood by those skilled in the art, the turntable will lock in a predetermined number of desired angular orientations in order to assure proper orientation of the array relative to the x-ray head 2.

The configuration of the present invention also lends to cross table imaging, as diagrammatically shown in Figs. 12 and 13. In this application, the digital array module 46 would be tilted to a vertical position when the drawer is fully extended as shown in Fig. 7. This can be

provided by installing the array on a tilt mechanism within the drawer, or installing the entire drawer on a tilt mechanism, as desired, as will be readily understood by those who are skilled in the art.

The array module 46 is a digital array such as that shown and described in the aforementioned U. S. Patent No. 5,381,014, entitled:"Large Area X-ray Imager and Method of Fabrication,"issued to L. S. Jeromin et al on January 10,1995, and incorporated by reference herein.

As shown in phantom in Fig. 6A, cable system 52 extends from the array and exits through a slot or opening 55 in the rear wall 37 of the carriage 26. The outer end of the cable 52 includes a connector plug 56 for connecting the array to a power source, control apparatus and the digital processing system for processing the digital image captured by the array (all not shown). Typically, the cable system 52 includes a spring-loaded accumulator sufficiently long to accommodate the extremity mode (Fig. 6) in either the landscape or portrait position. As the array 46 and drawer 25 are pushed into the under table mode (Fig. 4) the accumulator is biased to close up or gather the cable.

The digital bucky system of the present invention is particularly well-suited for retrofit applications, permitting current film-based analog x-ray systems to be converted to fully digital systems at a fraction of the cost of new digital installations. The retrofit digital bucky module comprises a series of nested drawers, with the outer drawer defining a carriage 26 which can be fit in the film bucky slot in a table system, a first drawer defining a digital bucky 25 and slidably mounted in the carriage for defining an array support or carrier, and a third drawer 48 slidable relative to the carrier drawer and carrying the grid such that the grid may be moved out of the way of the array in order to permit rotation between the landscape and portrait positions.

In addition, the digital bucky system of the invention provides versatility not readily available in the film-based system which it replaces. As diagrammatically shown in Figs. 8-15, the bucky system will accommodate a wide variety of configurations. Fig. 8 shows the array 46 in the portrait position within the table and with the bucky drawer 25 fully retracted into the carriage 26, with the array under the table top 4. Fig. 9 shows the array under the table top 4 as in Fig. 8., but with the array rotated ninety degrees for landscape imaging. Fig. 10 shows the bucky 25 fully extended from the table top 4 and the carriage 26 for extremity imaging, with the array 46 oriented in the same position as Fig. 8. Fig. 11 shows the bucky 25 positioned for extremity imaging with the array 46 oriented as in Fig 9. Figs. 12 and 13 show cross table orientations with the array 46

located above, adjacent and orthogonal to the table top 4, in both the portrait position (Fig. 12) and the landscape position (Fig. 13). Figs. 14 and 15 show the array 46 in the extended position when the tabletop 4 is in its fully tilted, or vertical position.

The digital array 46 as mounted in the bucky drawer 25 permits the various configuration orientations to be accomplished and allowing for substantially expanded versatility of the x-ray system over current configuration capabilities using the analog film buckys. Thus, the retrofit assembly not only converts the installed film based-analog system to a fully digital imaging system, but also increases the versatility over that of the analog system.

The subject invention provides a novel retrofit package both for converting existing film based analog x-ray systems to full digital imaging capability and for expanding the configuration capability to maximum versatility. While certain embodiments and features of the invention have been described in detail herein, it will be readily understood that the invention incorporates all of the enhancements and modifications within the scope and spirit of the following claims.