Abstract:
A digital radiography detector includes a housing and a radiographic image detector assembly. The housing has a first and second spaced planar members and four side walls defining a cavity. The radiographic image detector assembly is mounted within the cavity for converting a radiographic image to an electronic radiographic image. The detector assembly includes a scintillator screen and a detector array, and the detector assembly is bonded to the first planar member of the housing.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a Divisional of commonly assigned application U.S. Ser. No. 11/441,584 entitled “COMPACT AND DURABLE ENCASEMENT FOR A DIGITAL RADIOGRAPHY DETECTOR”, filed on May 26, 2006 in the names of Jadrich et al., and which is assigned to the assignee of this application. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates in general to medical imaging systems which use digital radiography detectors, and more particularly to a compact and durable encasement or housing for a digital radiography detector. 
       BACKGROUND OF THE INVENTION 
       [0003]    Traditional film-screen radiography has been used as a medical imaging diagnostic system for many years. X-rays are projected through a patient&#39;s body part to form a latent radiographic image on film contained in a cassette. The film is then be chemically or thermally processed to produce a visual radiographic image which can be used by a health care professional for diagnostic purposes. The delay in obtaining a diagnostic image, the use of a chemical or thermal processor, and the difficulty in providing the radiographic film outside of the immediate medical facility, has resulted in the development of digital radiographic imaging systems. Computed radiography (CR) digital systems have been developed in recent years that provide reusable CR plates which are scanned to produce a digital radiographic image. The CR systems still result in a delay in obtaining a diagnostic image due to the necessity of scanning an exposed CR plate. 
         [0004]    Digital radiography is achieving a growing acceptance as an alternative to film-screen and CR radiography systems. With digital radiography (DR), the radiation image exposures captured on radiation sensitive layers are converted, pixel by pixel, to digital image data which is stored and subsequently displayed on electronic display devices. One of the driving forces in the success of digital radiography is the ability to rapidly visualize and communicate a radiographic image via networks to a remote location for analysis and diagnosis by radiologists without the delay in sending chemically or thermally processed radiographic films by courier or through the mail. The use of chemical or thermal processors is also eliminated by digital radiography systems. 
         [0005]    The solid-state, ionizing radiation based image detectors used in projection digital radiography today are relatively large, heavy, and expensive. Additionally, a complete DR systems using this type of detector (hereafter DR detector) requires substantial capital investment to retrofit with existing X-ray equipment. For projection radiography, the detector array in these systems is typically a large-area pixilated device, fabricated on a glass substrate. The large-area detector array is expensive to fabricate, and it is also fragile to handle since the substrate is glass. As a result, DR detectors and systems are very expensive and the current market is small given the high cost of investment. 
         [0006]    DR detectors can either be direct or indirect conversion devices. Direct detectors use a material such as selenium in contact with a TFT array for conversion of X-ray photons. Indirect detectors use a scintillator screen for conversion of X-rays to visible light, through contact with a silicon photodiode and TFT array. 
         [0007]    The dimensions of medical radiographic cassettes/screens/films are specified under ISO 4090:2001(E) standard. This includes both conventional film and CR phosphor screens, with nominal imaging areas up to 35 cm×43 cm and 40 cm×40 cm (metric origin). Standard cassette dimensions are also specified as part of the ISO standard, including the maximum cassette thickness of 16.0 mm. 
         [0008]    U.S. Pat. No. 5,844,961, issued Dec. 1, 1998, inventors McEvoy et al., discloses a filmless digital x-ray system that uses a standard x-ray cassette housing. An external power source provides the power for the detector and associated electronic system. 
         [0009]    U.S. Patent Application Publication No. 2004/0227096, published Nov. 18, 2004, inventor Yagi, discloses a metal spring assembly for providing shock isolation to a radiation detector that provides limited shock isolation due to the stiffness of the metal type spring. 
         [0010]    U.S. Patent Application Publication No. 2005/0017188, published Jan. 27, 2005, inventor Yagi, discloses means to provide shock isolation to a radiation detector, in which shock absorption material is provided between inner and outer frames. This structure increases the size of the cassette. 
         [0011]    U.S. Pat. No. 6,296,386, issued Oct. 2, 2001, inventors Heidsieck et al., discloses a cassette for producing images for a radiography apparatus intended for mobile type cassettes. A handle and locking means are disclosed for locating the cassette within a reception housing. It is intended for use with mammography exposure devices, where locking features are advantaged since the reception housing can be in multiple orientations, where the cassette would be susceptible to dropping. The features disclosed are larger than the standard cassette and extend to contact the reception housing. This can limit its usage to specific types of x-ray equipment. 
         [0012]    U.S. Pat. No. 6,855,936, issued Feb. 15, 2005, inventor Yamamoto, discloses a cassette for use in a portable imaging environment. The cassette has a plurality of electrical connecting ports and a plurality of fixed handles. These allow for multiple detector orientation for specific radiographic exposures. 
         [0013]    U.S. Pat. No. 6,805,484, issued Oct. 19, 2004, inventors Kuramoto et al., discloses a portable device with at least one handle secured to the device housing. This handle is movably connected or pivoted, for the purpose of facilitating patient positioning only. 
         [0014]    U.S. Pat. No. 6,700,126, issued Mar. 2, 2004, inventor Watanabe, discloses a radiation detector which includes a shock absorber placed on any one of the side walls of the cassette. While this provides some lateral protection to the detector, it does not provide protection in the direction orthogonal to the detector plane. 
         [0015]    Accordingly, there is a need for a DR detector system that provides a compact encasement for housing the glass detector and supporting electronics so that it fits within the volume of existing standard film cassettes and meets the requirements of the ISO standard. There is also a need for a durable structure that protects the fragile detector from damage, due to physical shock or loads applied externally to the encasement. It is also desirable that the DR detector be usable for both typical x-ray exam room procedures as well as with portable imaging equipment. There is also a need that the detector be wireless, especially for portable imaging equipment where any electrical cables can interfere with user operation and handling of the portable detector. 
       SUMMARY OF THE INVENTION 
       [0016]    The present invention is directed to providing a system which addresses the problems and the needs discussed above. 
         [0017]    According to one aspect of the present invention there is provided a digital radiography detector comprising: a housing having first and second spaced planar members and four side walls defining a cavity; a radiographic image detector assembly mounted within the cavity for converting a radiographic image to an electronic radiographic image, wherein the detector assembly includes a detector array mounted on a stiffener; and a shock absorbing elastomer assembly located within the cavity for absorbing shock to the detector array/stiffener in directions perpendicular to and parallel to the detector array/stiffener. 
         [0018]    According to another aspect of the present invention there is provided a digital radiography detector comprising: a housing having first and second spaced planar members and four side walls; a radiographic image detector assembly mounted within the cavity for converting a radiographic image to an electronic radiographic image, wherein the detector assembly includes a screen and a detector array; and wherein the detector assembly is bonded to the first planar member of the housing. 
         [0019]    According to a further aspect of the present invention there is provided a digital radiography detector assembly comprising: a digital radiography detector having a housing having upper and lower planar members and four side walls; and a portable assembly detachably mounted to the detector; wherein the portable assembly includes at least one handle detachably mounted to a side wall of the detector housing. 
         [0020]    According to still another aspect of the present invention, there is provided a digital radiography detector assembly comprising: a digital radiography detector having a housing having upper and lower planar members and four side walls; and a portable assembly detachably mounted to the detector; the portable assembly includes a portable carrier having a cavity for detachably enclosing the detector within the cavity of the carrier. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The foregoing and other objects, features, and advantages of the invention will be apparent from the following more particular description of the embodiments of the invention, as illustrated in the accompanying drawings. The elements of the drawings are not necessarily to scale relative to each other. 
           [0022]      FIG. 1  is a diagrammatic view of typical x-ray equipment in today&#39;s x-ray examination room. 
           [0023]      FIG. 2  is a cross-sectional, elevational, diagrammatic view showing a single foam preload of an embodiment of the present invention. 
           [0024]      FIG. 3  is a sectional, top plan, diagrammatic view showing encapsulated corner elastomers of an embodiment of the present invention. 
           [0025]      FIG. 4  is a cross-sectional, elevational, diagrammatic view showing an alternate single foam preload of an embodiment of the present invention. 
           [0026]      FIG. 5  is a cross-sectional, elevational diagrammatic view showing dual foam preload of an embodiment of the present invention 
           [0027]      FIG. 6  is a sectional, top plan diagrammatic view showing corner elastomer of an embodiment of the present invention. 
           [0028]      FIG. 7  is a sectional, top plan, diagrammatic view showing full edge elastomer of an embodiment of the present invention. 
           [0029]      FIG. 8  is a cross-sectional, elevational, diagrammatic view showing the encasement/housing construction of an embodiment of the present invention. 
           [0030]      FIG. 9  is a cross-sectional, elevational, diagrammatic view showing an alternate housing construction of an embodiment of the present invention. 
           [0031]      FIG. 10  is top plan, diagrammatic view showing an embedded antenna for the embodiment of  FIG. 9 . 
           [0032]      FIG. 11  is a cross-sectional, elevational, diagrammatic view showing an encasement/housing with exterior bonded elastomer of an embodiment of the present invention. 
           [0033]      FIG. 12  is a cross-sectional, elevational, diagrammatic view showing an encasement/housing with adhesive bonded screen and detector array of an embodiment of the present invention. 
           [0034]      FIG. 13  is a cross-sectional. elevational, diagrammatic view showing an encasement/housing with elastomer in the housing of an embodiment of the present invention. 
           [0035]      FIGS. 14A ,  14 B, and  14 C are respective top plan, side elevational, and bottom plan diagrammatic views showing an encasement/housing with a battery pack holder and overall thickness of an embodiment of the present invention. 
           [0036]      FIG. 15  is a top plan, diagrammatic view showing telescoping and flexible antennas of an embodiment of the present invention. 
           [0037]      FIG. 16  is a top plan, diagrammatic view showing a detachable handle assembly for portable imaging of an embodiment of the present invention. 
           [0038]      FIG. 17  is a top plan, diagrammatic view showing a detachable handle and battery pack for portable imaging of an embodiment of the present invention. 
           [0039]      FIG. 18  is a top plan, diagrammatic view of a charging unit for the detachable handle and battery pack of an embodiment of the present invention. 
           [0040]      FIGS. 19A and 19B  are respective top plan and side elevational diagrammatic views showing a detachable carrier of an embodiment of the present invention. 
           [0041]      FIG. 20  is a top plan, diagrammatic view showing a detachable carrier and battery pack of an embodiment of the present invention. 
           [0042]      FIG. 21  is a cross-sectional, elevational, diagrammatic view showing the electronics and thermal interfaces of an embodiment of the present invention. 
           [0043]      FIG. 22  is a cross-sectional, elevational, diagrammatic view showing alternate electronics and thermal interfaces of an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0044]    The following is a detailed description of the preferred embodiments of the invention, reference being made to the drawings in which the same reference numerals identify the same elements of structure in each of the several figures. 
         [0045]    Referring now to  FIG. 1 , there is shown diagrammatically typical projection x-ray equipment used in an x-ray examination room. As shown, a patient  100  is positioned on a support  102 . An x-ray source  104  projects x-rays  106  through a body part of patient  100  to form a radiographic image of the body part which is detected by a digital detector housed in radiography cassette  108  mounted in support  102 . X-ray source  104  is activated and controlled by x-ray generator and control  110 . Support (Bucky)  102  can also house an antiscatter grid  112 , an auto exposure control sensor  114 ,  114 ′ (located above the radiography cassette for general radiography and below the radiography cassette for mammography). Detector control  116  is linked to the digital detector in cassette  108  and to capture system and exposure control  118 . Antiscatter grid  112  and auto exposure control  114 ,  114 ′ are linked to x-ray generator and control  110  which is linked to computer  110 . 
         [0046]    There are numerous types of x-ray equipment and configurations designed for specific radiographic procedures. These can include wall-stand, floor-mount, chest, or table units; designed for supine, upright, or other patient orientations. Major manufacturers of traditional x-ray equipment include, for example, Siemens, Philips, and General Electric. It has been estimated that worldwide volumes of traditional x-ray equipment is well over 100,000 units. Because of these large volumes, it is an object of the present invention to replace/retrofit film or CR screen cassette with a digital radiography detector that fits within the same cassette volume accepted by x-ray equipment. 
         [0047]    An embodiment of the present invention is shown in  FIGS. 2 and 3 . As shown, DR detector  200  includes upper housing  202 , lower housing  204 , secured together and forming a cavity  206 . Mounted within cavity  206  are detector array  208  mounted on stiffener  210 , screen (scintillator)  212 , compliant foam member  214 , elastomer shock-absorbing supports  216  mounted on stop ledges  217  of lower housing  206 , flex circuits  218  connected between detector array  208  and electronics  220 . A wireless interface  222  is connected to electronics  220 . A battery pack  224  is mounted in a compartment  226  of lower housing  204 . Battery pack  224  and electronics  220  are thermally coupled to sheet metal member  228  which acts as a heat sink for heat generated by battery pack  224  and electronics  220 . X-rays are projected to detector  200  in the direction of arrow A. 
         [0048]    Indirect DR systems use an intensifying phosphor screen (scintillator)  212  to convert x-ray radiation into visible light. A detailed explanation of this conversion process and detection system is disclosed in U.S. Pat. No. 5,650,626, issued Jul. 22, 1997, entitled “X-ray Imaging Detector with Thickness and Composition Limited Substrate”, inventors Trauernicht et al. The embodiment of  FIGS. 2 and 3  has the scintillator screen  212  placed in contact with detector array  208  by means of compliant foam member  214  which applies and maintains this physical contact. Physical contact between screen  212  and detector array  208  can also be applied by means such as a spring or a plurality of springs. Further, an index-matching type optical adhesive could be used to bond screen  212  directly to detector array  208 , so that compliant foam member is not needed. It is important that physical contact be maintained across the entire active area of the detector array  208 , so that uniform and efficient transfer of the converted visible light is achieved. 
         [0049]    To comply with ISO 4090.2001(E) standard, packaging of the detector array and supporting electronics becomes very challenging. There is limited space for these components in all directions (X, Y, Z). First, flex circuits connecting the detector array and electronics need to be wrapped underneath the array. Second, use of a self-contained battery and battery pack within the DR detector is preferred. In order to comply with the 16 mm cassette thickness, the self-contained battery and battery pack needs to be extremely thin. For example, a lithium polymer rechargeable battery such as Ultralife UBC36106102 could be used. This type of rechargeable battery is only 4.0 mm thick. It is noted that the present invention is not limited to a self-contained battery, but could be energized through an external power source. Detector array  208  is fabricated onto a substrate material such as Corning 1737 display glass, for example, or a substrate with a chemical composition, such as disclosed in U.S. Pat. No. 5,650,626. Display glass is typically 0.7 mm thick, and susceptible to breakage, especially when a large-area, such as 43 cm×43 cm, is used. For durability reasons, the detector array  208  is attached to a stiffener  210  in an embodiment of the present invention. The stiffener is made of a lightweight composite that has similar thermal coefficient of expansion to the substrate material, but significantly higher bending stiffness than the substrate. For example, the composite can be made of a core using Rohacell IG closed-cell rigid foam, sandwiched between thin plies of directionally oriented carbon fiber. 
         [0050]    Attachment of detector array  208  to stiffener  210  can be applied using a double-sided pressure sensitive tape such as 3M 9832HL, for example, or a removable thermal release adhesive such as Nitto Denko REVALPHA. Bending stiffness of the composite should be on the order of 10× greater than the substrate material. This will result in the composite supporting the substrate material in such a way as to minimize deflection under extreme load or shock conditions. Otherwise, fracture or breakage of the substrate material could occur. So that the detector  208  and stiffener  210  do not distort under an operational temperature range, it is desirable that the Coefficient of Thermal Expansion (CTE) of the detector  208  and stiffener  210  be similar. Display glass has a CTE around 4×10−6 per degrees C., whereas carbon fiber based composites can range between: −0.5×10−6 and +5.0×10−6 per degrees C., depending on the type of fiber, fiber orientation, and core material used. The uniqueness of the composite structure is that the fiber type and orientation can be adjusted to obtain desired thermal characteristics. Similar composite structures are being used today to mount large glass telescope mirrors for space exploration. 
         [0051]    As shown in  FIGS. 2 and 3 , the attached detector  208  and stiffener  210  are mounted to elastomer supports  216  for protection against external shock and vibration, which further enhances the durability of the overall DR detector  200 . Four encapsulated elastomer supports  216  are each located in the four corners of the detector/stiffener panel  208 / 210 . The elastomer support  216  should be relatively flexible to absorb shock. For example, a polyurethane type material with a hardness of 20-40 Shore A durometer could be used. The elastomer supports  216  are held against and within mating corners of upper and lower housings  202 ,  204 . 
         [0052]    As shown in  FIG. 4 , DR detector  400  includes upper and lower casings  402  and  404  mounted to four-sided external frame  406 . An internal frame  408  is mounted to lower casing  404 . Foam layer  410  preloads screen  412 , detector  414 , stiffener  416  in the direction of arrow  418  against inner frame  408 . Inner frame  408  can be attached to stiffener  416  via adhesive or conventional fasteners for locating components in the lateral or X direction. There are column features on the inner frame  408  that locate the inner frame  408  against lower casing  404 . Flexible circuit  420  is also provided. Elastomer members  421  are used as a buffer against physical shock in the X direction, and further aid in keeping the preloaded components centered in the housing. Further foam layer  410  provides shock isolation in the Z direction, while at the same time provides an alternate means of isolation in the X direction, through shearing of the foam layer in the direction of arrow  440 . Electronics  422  and  424  can have a heat conduction path directly through the lower casing via thermal pad  426 . An antenna  428  and battery  430  are also included in detector  400 . 
         [0053]      FIGS. 5 and 6  show a modification of the DR detector shown in  FIGS. 2 and 3 . As shown DR detector  500  includes upper housing  502 , lower housing  504 , secured together and forming a cavity  506 . Mounted within cavity  506  are detector array  508  mounted on stiffener  510 , screen (scintillator)  512 , compliant foam members  514  and  515 , elastomer shock-absorbing supports  516 , flex circuits  518  connected between detector array  508  and electronics  520 . A wireless interface  522  is connected to electronics  520 . A battery pack  524  is mounted in a compartment  526  of lower housing  504 . Battery pack  524  and electronics  520  are thermally coupled to structural member  528  which acts as a heat sink for heat generated by battery pack  524  and electronics  520 . X-rays are projected to detector  500  in the direction of arrow B. In this embodiment, foam members  514 ,  515  support both front and back of the detector array—stiffener pair  508 ,  510 . There are advantages of this configuration. First, uniform pressure is applied by means of the foam to both sides of the detector array  508  and stiffener  510 , resulting in no static deformation of this pair. Second, there will not be any localized stress applied to the corners of the pair since the corner elastomer supports do not encapsulate the pair. 
         [0054]      FIG. 7  shows an embodiment of the invention where the corner elastomer supports are replaced with elastomer supports along two full edges of the detector. For ease of discussion, only components are shown to illustrate the embodiment. As shown, DR detector  700  includes a housing  702 , detector array  704 , with flex circuits  706 . Elongated elastomer supports  708  are located along edges  710  and  712  where flex circuits  706  are not located. If flex circuits are needed on all four sides, this arrangement would not be possible. The advantage of this embodiment is that having additional contact along the width and length can further reduce stress imparted to the detector array  704 . 
         [0055]      FIG. 8  shows construction of the housing of the DR detector. As shown, DR detector  800  has upper housing  802  and lower housing  804 . Upper housing  802  has upper casing  806  and upper frame  808 , while lower housing  804  has lower casing  810  and lower frame  812 . Lower casing  810  has battery pack holder  814 . Upper and lower casings  806 ,  810  are preferably a lightweight composite, similar to that disclosed in U.S. Pat. No. 5,912,944, issued on Jun. 15, 1999, inventor Budinski et al. The composite disclosed is a composite structure of polypropylene core, sandwiched between thin aluminum sheets. This composite material is manufactured by Corus, under the product name HYLITE™. In addition to being light in weight, this material has high stiffness needed for durability of the housing. Similarly, a carbon fiber based composite like that of the stiffener could be used. Several tradeoffs need to be considered using a composite material in this application, as follows: a) overall weight, b) material cost, c) radiographic absorption, and d) material stiffness. Several of these parameters are discussed in detail in U.S. Pat. No. 5,912,914, issued Jun. 15, 1999, inventor Dittbenner. 
         [0056]    As further shown in  FIG. 8 , upper and lower frame sections  808  and  812  are attached directly to the upper and lower casings  806  and  810 , respectively. Frames  808  and  812  add stiffness to the relatively thin casings  806 ,  810 , and are preferably made of a material with a high stiffness to weight ratio. The high stiffness is needed for durability reasons, so the housing does not distort under extreme load or shock conditions. Materials such as aluminum, magnesium, and titanium fit in this category. However, filled thermoplastics can be considered as well, and may have some advantage for potential injection molding the frame directly to the casings. The lower casing in a DR detector configuration with self-contained power would require a pocket, e.g., pocket  814 , for mounting a battery pack holder. A modification of the detector housing of  FIG. 8  is shown in  FIG. 11 . As shown, a thin bonded elastomer  820  surrounds the exterior portions of frames  808  and  812 . This provides additional protection against shock and damage to the detector housing and internal components. 
         [0057]    An alternate housing construction for a DR detector is shown in  FIGS. 9 and 10 . As shown in  FIG. 9 , upper and lower casings  902  and  904  of DR detector  900  are attached to a four sided frame  906 . An advantage of this configuration is for assembly and test of the detector electronics. The upper casing  902  would first be attached to frame  906 . This attachment can be done via conventional fasteners or other adhesive fastening means. The upper casing  902  and frame  906  would be placed upside down, where the foam, screen, detector array, stiffener, and internal frame (see  FIG. 4 ), are placed in that order. All detector electronics would then be attached to the internal frame. Having the lower casing not installed at this point, allows for test and debug of all detector electronics. Once this is completed, the lower casing can be attached via fasteners or other means, thus preloading the entire assembly. 
         [0058]    Another advantage of the latter configuration is for x-ray transmission and thermal transfer characteristics. The upper casing as previously discussed, should be made of a material that has good x-ray transmission characteristics such as HYLITE™ or carbon fiber composites. The lower casing is preferably made of a lightweight material that is thermally conductive such as aluminum or magnesium. A thermally conductive material allows a heat dissipation path outside of the detector through a thermal pad material. 
         [0059]    Another alternative shown in  FIG. 9  is to have a recessed feature around the perimeter of the frame  906  for embedding an antenna. As shown, frame  906  has a recess  908  into which antenna  910  is held in place by insert  912 . The frame  906  is preferably made of a metal that is high in stiffness. In order to have enough signal strength for wireless transmission, the antenna would be exterior to any metal components. Having the antenna embedded between the exterior of the frame and insert as shown, helps in signal transmission. The insert  912  is preferably made of a non-metal which does not attenuate the wireless signal, such as plastic or elastomer. The insert  912  would be wrapped around the perimeter of the frame, and bonded against the recess  908 . Additionally, the insert  912  can protrude slightly from frame  906 , thus providing additional shock isolation in the x-direction for the assembly. 
         [0060]    Another view of this structure is shown in  FIG. 10 , and can have a plurality of antennas  910 ,  910 ′ embedded in the frame. A plurality of antennas will increase the likelihood of proper signal transmission once the detector assembly is installed in a Bucky. Battery pack holder  914  and electronics  916  are also shown. 
         [0061]      FIGS. 12 ,  13 , and  14 A- 14 C show another embodiment of the invention. As shown in  FIG. 12 , DR detector  1200  includes upper housing  1202  having upper casing  1204  and upper frame  1206 , and lower housing  1208  having lower casing  1210  and lower frame  1212 . Lower casing  1210  has a battery pack holder  1214 . Scintillator screen  1216  is attached to upper casing by adhesive  1218  and detector array  1220  is attached to screen  1216  by adhesive  1222 . With the understanding that upper casing  1204  is self-rigid, this arrangement can prevent the need for attaching a stiffener to the base of the detector array. Additionally, this configuration can allow more space for packaging electronics, since foam is no longer needed. Another variation shown in  FIG. 13  is to have an elastomer  1230  between upper housing frame  1206  and upper casing  1204 . This would provide additional shock protection. once the detector array, electronics, and all other components are mounted, the upper and lower housing members are attached and sealed together. Exterior views of the complete DR detector are shown in  FIGS. 14A-14C   
         [0062]    The DR detector shown in  FIG. 15  is useful for an application with a wireless interface. As shown, DR detector  1500  has a frame  1502 , a casing  1504 , electronics  1506 , battery pack holder  1508 , wireless interface  1510 , and flexible or telescoping antenna  1512 . The flexible antenna can extend around the detector housing. Some Bucky configurations are surrounded with metal, and this can result in signal strength loss between an internal transmitter within the DR detector and receiver at the DR system level. In this event, an optional antenna would be necessary to extend outside the Bucky. 
         [0063]    Portable imaging is another large market opportunity for future DR systems. Portable imaging systems are typically used in emergency rooms, trauma center, or operating room, where fast turnaround of the images is necessary. These systems typically have a mobile-based x-ray source on wheels with a portable cassette using radiographic capture media. Ergonomically, it is desirable to have a handle on these cassettes for portability and to assist during any patient handling and insertion. Further, it is desirable that the portable cassette be extremely light in weight due to frequent handling of the device. An example of today&#39;s portable digital radiography detectors is the Canon CXDI-50G. This device has a 35 cm×43 cm specified imaging area, with the overall portable assembly weighing 11 pounds. This is considered too heavy for repeated and daily handling of these devices. An overall detector weight of 8 pounds is considered to be desirable for ergonomic needs. 
         [0064]    It is an object of the present invention to provide a flexible and extensible configuration of the DR detector, so that it can be used for portable imaging, as well as the x-ray exam room applications previously discussed. One embodiment of portable detector configuration is shown in  FIG. 16 , where a detachable handle can be mounted to a plurality of edges on the DR detector. As shown, DR detector  1600  includes a casing  1602 , frame  1604 , handle mounting apertures  1605 , and battery pack holder  1612 . A handle  1606  having latches  1608  is detachably mounted to detector  1600 . Latches  1608  of handle  1606  engage with apertures  1605  along the edge  1607  or  1610  of detector  1600 . An advantage of this configuration is that the detachable handle can be mounted for landscape or portrait imaging, depending on the ergonomic preference or specific imaging procedure. The attachment of the handle to the DR detector can either be through a quick latch type device, or with conventional fasteners requiring a tool. The latter attachment means could be advantaged if orientation change is not frequently required. 
         [0065]      FIG. 17  shows a modification of the system of  FIG. 16 , in which the detachable handle  1606 ′ includes rechargeable batteries  1620  to power the DR detector  1600 , and possibly an antenna  1622  for wireless communication. This extension of the wireless antenna would only be necessary if signal transmission is not adequate as previously discussed, otherwise an antenna embedded in the DR detector housing would be appropriate for portable imaging. A separate charging unit such as shown in  FIG. 18  can be used to recharge the rechargeable (e.g., lithium polymer) batteries. As shown, battery charger  1650  has a plug  1656  and a terminal  1654  for engaging with a terminal  1624  on handle  1606 ′ when handle  1606 ′ is mounted in apertures  1652  of charger  1650 . In this embodiment, the battery pack embedded in the DR detector would no longer be required. Since the structural components previously discussed are all lightweight composite materials, it is feasible that overall weight of the portable DR detector configuration could achieve 8 pounds maximum. 
         [0066]      FIGS. 19A and 19B  show an alternate portable imaging configuration in which the DR detector is detachably mounted in a portable carrier. This configuration provides additional structural rigidity surrounding the DR detector but also adds additional weight. As shown, DR detector  1900  is detachably received in cavity  1904  of portable carrier  1902 . Latch pin  1906  on carrier  1902  locks into aperture  1908  on detector  1900 . The latch pin facilitates locking and releasing the detector  1900  relative to the carrier  1902 .  FIG. 20  shows a portable carrier  1902 ′ having rechargeable batteries  1910 , antenna  1912 , and connector  1914 . 
         [0067]    It is known that detector arrays used in today&#39;s DR systems are sensitive to temperature variations affecting uniformity of the detector. It is another object of the present invention to provide a passive cooling means to transfer heat away from all heat source components within the DR detector. This would include the electronics, battery, and ASIC electronics attached to the flex circuits as shown in  FIG. 21 . As shown, components of DR detector  2100  include detector array  2102 , stiffener  2104 , air gap  2106 , lead shield  2108 , structural member  2110 , thermally conductive member  2112 , ASIC  2114 , electronics  2116 , wireless interface  2118 , battery pack  2120 , and temperature sensor  2122 . Thermally conductive member  2112  is made of thermally conductive material such as Panasonic Pyrolytic Graphite Sheet (PGS). This material is very efficient in transferring heat laterally away from the heat source (X and Y directions), due to the directional orientation of the graphite. The thermally conductive material would be sandwiched between the heat sources as shown, and a thermally conductive structural member  2110  to further dissipate the heat. A lead shield  2108  may be used between the x-ray source and electronics to absorb radiation and prevent possible damage to the electronics over time. Additionally, lead or other heavy metal could be embedded or attached to the stiffener for similar x-ray absorption purposes. 
         [0068]    It is preferred that the structural member be separated from the stiffener so that heat is not directly conducted through the stiffener and detector array. This can be accomplished through air gap  2106 , or some thermal insulating material such as the foam shown in  FIG. 5 . 
         [0069]    A temperature sensor  2122  or plurality of temperature sensors can be attached in as close proximity to the detector array as possible. The sensor(s) would be used to monitor local or ambient temperature of the detector array through the electronics, and possibly correct for any temperature non-uniformities captured during DR detector manufacturing. 
         [0070]      FIG. 22  shows another embodiment of thermal management in a DR detector. As shown DR detector  2200  includes detector array  2202 , stiffener  2204 , flex circuit  2206 , lead shield  2208 , lower casing  2210 , internal frame  2212 , battery pack  2214 , ASIC  2216 , Printed Circuit Board(s) (PCBs)  2218 , electronic component(s)  2220 , wireless interface  2222 , and thermally conductive gap pad  2224 . The embodiment allows transfer of heat out of the housing through the lower casing. This allows for natural convection and radiation to remove heat from the outside of the housing. The ASIC and all primary heat dissipating electronic components transfer heat through the thermally conductive pad and the lower casing. A thermally conductive material such as Panasonic PGS can be used for the thermal pad. Alternatively, a thermally conductive gap pad material such as Bergquist 3000S30 could be used. An advantage of a gap pad material is that it will compress and accommodate height differences of electronic components, compared with the very thin Panasonic PGS material. Thickness of gap pad materials range from 0.25-3.0 mm, compared with PGS at 0.10 mm thickness only. 
         [0071]    The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 PARTS LIST 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                  100 
                 patient 
               
               
                   
                  102 
                 support 
               
               
                   
                  104 
                 x-ray source 
               
               
                   
                  106 
                 x-rays 
               
               
                   
                  108 
                 radiography cassette 
               
               
                   
                  110 
                 x-ray generator and control 
               
               
                   
                  112 
                 antiscatter grid 
               
               
                   
                  114, 114′ 
                 auto exposure control 
               
               
                   
                  116 
                 detector control 
               
               
                   
                  118 
                 host PC computer 
               
               
                   
                  200 
                 DR detector 
               
               
                   
                  202 
                 upper housing 
               
               
                   
                  204 
                 lower housing 
               
               
                   
                  206 
                 cavity 
               
               
                   
                  208 
                 detector array 
               
               
                   
                  210 
                 stiffener 
               
               
                   
                  212 
                 scintillator screen 
               
               
                   
                  214 
                 compliant foam member 
               
               
                   
                  216 
                 elastomer supports 
               
               
                   
                  217 
                 stop ledges 
               
               
                   
                  218 
                 flex circuits 
               
               
                   
                  220 
                 electronics 
               
               
                   
                  222 
                 wireless interface 
               
               
                   
                  224 
                 battery pack 
               
               
                   
                  226 
                 compartment 
               
               
                   
                  228 
                 structural member 
               
               
                   
                  400 
                 DR detector 
               
               
                   
                  402 
                 upper casing 
               
               
                   
                  404 
                 lower casing 
               
               
                   
                  406 
                 external frame 
               
               
                   
                  408 
                 internal frame 
               
               
                   
                  410 
                 foam layer 
               
               
                   
                  412 
                 screen 
               
               
                   
                  414 
                 detector 
               
               
                   
                  416 
                 stiffener 
               
               
                   
                  418 
                 arrow 
               
               
                   
                  420 
                 flexible circuit 
               
               
                   
                  421 
                 elastomer member 
               
               
                   
                  422, 424 
                 electronics 
               
               
                   
                  426 
                 thermal pad 
               
               
                   
                  428 
                 antenna 
               
               
                   
                  430 
                 battery 
               
               
                   
                  440 
                 arrow 
               
               
                   
                  500 
                 DR detector 
               
               
                   
                  502 
                 upper housing 
               
               
                   
                  504 
                 lower housing 
               
               
                   
                  506 
                 cavity 
               
               
                   
                  508 
                 detector array 
               
               
                   
                  510 
                 stiffener 
               
               
                   
                  512 
                 screen 
               
               
                   
                  514, 515 
                 compliant foam members 
               
               
                   
                  516 
                 elastomer supports 
               
               
                   
                  518 
                 flex circuits 
               
               
                   
                  520 
                 electronics 
               
               
                   
                  522 
                 wireless interface 
               
               
                   
                  524 
                 battery pack 
               
               
                   
                  526 
                 compartment 
               
               
                   
                  528 
                 structural member 
               
               
                   
                  700 
                 DR detector 
               
               
                   
                  702 
                 housing 
               
               
                   
                  704 
                 detector array 
               
               
                   
                  706 
                 flex circuits 
               
               
                   
                  708 
                 elastomer supports 
               
               
                   
                  710, 712 
                 edges 
               
               
                   
                  800 
                 DR detector 
               
               
                   
                  802 
                 upper housing 
               
               
                   
                  804 
                 lower housing 
               
               
                   
                  806 
                 upper casing 
               
               
                   
                  808 
                 upper frame 
               
               
                   
                  810 
                 lower casing 
               
               
                   
                  812 
                 lower frame 
               
               
                   
                  814 
                 battery pack holder 
               
               
                   
                  820 
                 elastomer 
               
               
                   
                  900 
                 DR detector 
               
               
                   
                  902, 904 
                 upper and lower casings 
               
               
                   
                  906 
                 frame 
               
               
                   
                  908 
                 recess 
               
               
                   
                  910, 910′ 
                 antenna 
               
               
                   
                  912 
                 insert 
               
               
                   
                  914 
                 battery pack holder 
               
               
                   
                  916 
                 electronics 
               
               
                   
                 1200 
                 DR detector 
               
               
                   
                 1202 
                 upper housing 
               
               
                   
                 1204 
                 upper casing 
               
               
                   
                 1206 
                 upper frame 
               
               
                   
                 1208 
                 lower housing 
               
               
                   
                 1210 
                 lower casing 
               
               
                   
                 1212 
                 lower frame 
               
               
                   
                 1214 
                 battery pack holder 
               
               
                   
                 1216 
                 scintillator screen 
               
               
                   
                 1218 
                 adhesive 
               
               
                   
                 1220 
                 detector array 
               
               
                   
                 1222 
                 adhesive 
               
               
                   
                 1230 
                 elastomer 
               
               
                   
                 1500 
                 DR detector 
               
               
                   
                 1502 
                 frame 
               
               
                   
                 1504 
                 casing 
               
               
                   
                 1506 
                 electronics 
               
               
                   
                 1508 
                 battery pack holder 
               
               
                   
                 1510 
                 wireless interface 
               
               
                   
                 1512 
                 antenna 
               
               
                   
                 1600 
                 DR detector 
               
               
                   
                 1602 
                 casing 
               
               
                   
                 1604 
                 frame 
               
               
                   
                 1605 
                 apertures 
               
               
                   
                 1606, 1606′ 
                 handle 
               
               
                   
                 1607 
                 edge 
               
               
                   
                 1608 
                 latches 
               
               
                   
                 1610 
                 edge 
               
               
                   
                 1612 
                 battery pack holder 
               
               
                   
                 1620 
                 rechargeable batteries 
               
               
                   
                 1622 
                 antenna 
               
               
                   
                 1624 
                 terminal 
               
               
                   
                 1650 
                 battery charger 
               
               
                   
                 1652 
                 apertures 
               
               
                   
                 1654 
                 terminal 
               
               
                   
                 1656 
                 plug 
               
               
                   
                 1900 
                 DR detector 
               
               
                   
                 1902, 1902′ 
                 portable carrier 
               
               
                   
                 1904 
                 cavity 
               
               
                   
                 1906 
                 latch pin 
               
               
                   
                 1908 
                 aperture 
               
               
                   
                 1910 
                 rechargeable batteries 
               
               
                   
                 1912 
                 antenna 
               
               
                   
                 1914 
                 connector 
               
               
                   
                 2100 
                 DR detector 
               
               
                   
                 2102 
                 detector array 
               
               
                   
                 2104 
                 stiffener 
               
               
                   
                 2106 
                 air gap 
               
               
                   
                 2108 
                 lead shield 
               
               
                   
                 2110 
                 structural member 
               
               
                   
                 2112 
                 thermally conductive member 
               
               
                   
                 2114 
                 ASIC 
               
               
                   
                 2116 
                 electronics 
               
               
                   
                 2118 
                 wireless interface 
               
               
                   
                 2120 
                 battery pack 
               
               
                   
                 2122 
                 temperature sensor 
               
               
                   
                 2200 
                 DR detector 
               
               
                   
                 2202 
                 detector array 
               
               
                   
                 2204 
                 stiffener 
               
               
                   
                 2206 
                 flex circuit 
               
               
                   
                 2208 
                 lead shield 
               
               
                   
                 2210 
                 lower casing 
               
               
                   
                 2212 
                 internal frame 
               
               
                   
                 2214 
                 battery pack 
               
               
                   
                 2216 
                 ASIC 
               
               
                   
                 2218 
                 PCB(s) 
               
               
                   
                 2220 
                 electronic component(s) 
               
               
                   
                 2222 
                 wireless interface 
               
               
                   
                 2224 
                 thermally conductive gap pad