Abstract:
Disclosed herein is a computed tomography (CT) detector module, for coupling with a collimator rail. The CT detector module includes a CT detector pack, a printed circuit board, and electrical conductor, and a substrate. The electrical conductor is disposed between and in electrical communication with the CT detector pack and the printed circuit board. The substrate has a slot and is disposed between the CT detector pack and the circuit board such that the electrical conductor is routed through the slot.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     This application relates generally to Computed Tomography (CT) systems. In particular, the invention relates to an interconnect and packaging method for multi-slice CT detector modules. CT systems are used to obtain non-invasive sectional images of test objects, particularly internal images of human tissue for medical analysis and treatment. In a computed tomography (CT) system, an x-ray source projects a fan-shaped beam that is collimated to lie within an X-Y plane of a Cartesian coordinate system, termed the “imaging plane.” The x-ray beam passes through the object being imaged, such as a medical patient, and impinges upon a multi-row multi-column detector array. The detector array comprises a plurality of detector elements. The detector system converts incident X-rays of varying intensity into electronic signals. CT system detector electronics use integrated circuit boards that process electronic the signals during CT system scans.  
         [0002]     Two types of radiation detectors are used in CT systems: scintillation detectors and direct conversion detectors. New pixilated direct-conversion (DC) CT detector modules require stringent packaging, interconnect and mounting solutions to be properly installed on a CT scanner collimator-grid assembly.  
         [0003]     Compatibility between both types of radiation detectors is desirable so that the new DC modules may be mounted directly onto a nominal collimator while meeting all required common design specifications (for example, independent module mount/remount capabilities, high-precision alignment to the collimator assembly using existing dual alignment pin, “pin-in-pack” methods, thermal heat transfer performance, and mechanical robustness).  
         [0004]     The ability to upgrade the CT detector modules and components must also be provided, in particular, a configuration is needed that supports both 20 mm/32 slice and 40 mm/64 slice detector-pack 2D tilability.  
       BRIEF SUMMARY OF THE INVENTION  
       [0005]     Disclosed herein is a computed tomography (CT) detector module, for coupling with a collimator rail. The CT detector module includes a CT detector pack, a printed circuit board, and electrical conductor, and a substrate. The electrical conductor is disposed between and is in electrical communication with the CT detector pack and the printed circuit board. The substrate has a slot and is disposed between the CT detector pack and the circuit board such that the electrical conductor is routed through the slot.  
         [0006]     Further disclosed herein is a computed tomography (CT) detector array. The CT detector array includes a first and a second collimator rail, a plurality of CT detector modules, and an elastomer conducting contact. The second collimator rail has a high voltage strip and is spaced adjacent to the first collimator rail. Each of the CT detector modules has a CT detector pack, a printed circuit board, an electrical conductor, and a substrate. The electrical conductor is disposed between and is in electrical communication with the CT detector pack and the printed circuit board. The substrate has a slot and is disposed between the CT detector pack and the circuit board such that the electrical conductor is routed through the slot and the substrate is mounted on the first collimator rail and the second collimator rail. The elastomer conducting contact is disposed within the substrate and is in electrical communication with the CT pack such that the elastomer conducting contact and the high voltage strip are electrically connected.  
         [0007]     Yet further disclosed herein is a method for electrically connecting a computed tomography (CT) module to a CT system. A CT detector pack is attached to a substrate having a slot. An electrical conductor is routed from the CT detector pack, through the substrate slot, and to a printed circuit board. The substrate is mounted to a plurality of collimator rails such that an electrical connection is formed when the substrate is mounted to the collimator rails. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     Referring to the exemplary drawings wherein like elements are numbered alike in the accompanying Figures:  
         [0009]      FIG. 1  is a perspective view of a CT imaging system and a patient disposed for imaging in accordance with an exemplary embodiment;  
         [0010]      FIG. 2  is a block schematic diagram of the CT imaging system of  FIG. 1  for use in accordance with an exemplary embodiment;  
         [0011]      FIG. 3  is a perspective view of an exemplary radiation detector array for use in accordance with an embodiment of the invention;  
         [0012]      FIG. 4  is a perspective view of an exemplary CT detector module and printed circuit board for use in accordance with an embodiment of the invention;  
         [0013]      FIG. 5  is a perspective view of an exemplary substrate for use in accordance with an embodiment of the invention;  
         [0014]      FIG. 6  is a top view of an exemplary CT detector module for use in accordance with the invention;  
         [0015]      FIG. 7  is a side view of an exemplary CT detector module for use in accordance with an embodiment of the invention;  
         [0016]      FIG. 8  is a top view of an exemplary CT detector module mounted on collimator rails for use in accordance with an embodiment of the invention;  
         [0017]      FIG. 9  is a side view of an exemplary CT detector module mounted on collimator rails for use in accordance with an embodiment of the invention;  
         [0018]      FIG. 10  is a perspective view of an exemplary CT detector module for use in accordance with an embodiment of the invention;  
         [0019]      FIG. 11  is a perspective view of an exemplary CT detector module and printed circuit board for use in accordance with an embodiment of the invention; and  
         [0020]      FIG. 12  is a partial view of an exemplary CT detector module for use in accordance with an embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]      FIGS. 1 and 2  illustrate an exemplary CT imaging system  100  including a gantry  105  having an x-ray source  110 , a radiation detector array  115 , a patient support structure  120  and a patient cavity  125 , wherein the x-ray source  110  and the radiation detector array  115  are opposingly disposed so as to be separated by the patient cavity  125 . In an exemplary embodiment, a patient  130  is disposed upon the patient support structure  120 , which is then disposed within the patient cavity  125 . The x-ray source  110  projects an x-ray beam  135  toward the radiation detector array  115  so as to pass through the patient  130 . In an exemplary embodiment, the x-ray beam  135  is collimated by a collimate (not shown) so as to lie within an X-Y plane of a Cartesian coordinate system referred to as an “imaging plane”. After passing through and becoming attenuated by the patient  130 , the attenuated x-ray beam  140  is received by the radiation detector array  115 . The radiation detector array  115  receives an attenuated x-ray beam  140  and produces an electrical signal responsive to the intensity of the attenuated x-ray beam  140 .  
         [0022]     In addition, the x-ray source  110  and the radiation detector array  115  are rotatingly disposed relative to the gantry  105  and the patient support structure  120 , so as to allow the x-ray source  110  and the radiation detector array  115  to rotate around the patient support structure  120  when the patient support structure  120  is disposed within the patient cavity  125 . X-ray projection data is obtained by rotating the x-ray source  110  and the radiation detector array  115  around the patient  130  during a scan. The x-ray source  110  and the radiation detector array  115  communicate with a control mechanism  150  associated with the CT imaging system  100 . The control mechanism  150  controls the rotation and operation of the x-ray source  110  and the radiation detector array  115 .  
         [0023]     In an exemplary embodiment, the control mechanism  150  includes an x-ray controller  155  communicating with an x-ray source  110 , a gantry motor controller  160 , and a data acquisition system (DAS)  165  communicating with a radiation detector array  115 . The x-ray controller  155  provides power and timing signals to the x-ray source  110 , the gantry motor controller  160  controls the rotational speed and angular position of the x-ray source  110 , and the radiation detector array  115  and the DAS  165  receive the electrical signal data for subsequent processing. In an exemplary embodiment, the CT imaging system  100  also includes an image reconstruction device  170 , a data storage device  175  and a processing device  180 , wherein the processing device  180  communicates with the image reconstruction device  170 , the gantry motor controller  160 , the x-ray controller  155 , the data storage device  175 , an input device  185  and an output device  190 . The CT imaging system  100  can also include a table controller  196  in communication with the processing device  180  and the patient support structure  120 , so as to control the position of the patient support structure  120  relative to the patient cavity  125 .  
         [0024]     In accordance with an exemplary embodiment, the patient  130  is disposed on the patient support structure  120 , which is then positioned by an operator via the processing device  180  so as to be disposed within the patient cavity  125 . The gantry motor controller  160  is operated via processing device  180  so as to cause the x-ray source  110  and the radiation detector array  115  to rotate relative to the patient  130 . The x-ray controller  155  is operated via the processing device  180  so as to cause the x-ray source  110  to emit and project a collimated x-ray beam  135  toward the radiation detector array  115  and hence toward the patient  130 . The x-ray beam  135  passes through the patient  130  so as to create an attenuated x-ray beam  140 , which is received by the radiation detector array  115 .  
         [0025]     The radiation detector array  115  receives the attenuated x-ray beam  140 , produces electrical signal data responsive to the intensity of the attenuated x-ray beam  140  and communicates this electrical signal data to the DAS  165 . The DAS  165  then converts this electrical signal data to digital signals and communicates both the digital signals and the electrical signal data to the image reconstruction device  170 , which performs high-speed image reconstruction. This information is then communicated to the processing device  180 , which stores the image in the data storage device  175  and displays the digital signal as an image via output device  190 . In accordance with an exemplary embodiment, the output device  190  includes a display screen  194  having a plurality of discrete pixel elements  192 .  
         [0026]      FIG. 3  further illustrates an exemplary radiation detector array  115 , also referred to as a CT detector array, having collimator rails  118  and a CT detector module  200 . The radiation detector array  115  includes a plurality of CT detector modules  200  disposed along an outer periphery of the collimator rails  118 , although only one CT detector module  200  is depicted in  FIG. 3  for clarity of illustration.  
         [0027]     Exemplary embodiments of the CT detector module  200  include several features to allow for close compatibility between new pixilated direct conversion (DC) CT detector modules, for example cadmium telluride (CdTe) modules or cadmium zinc telluride (CZT) modules, which may be fabricated by, for example, a company such as DxRay, Inc., and scintillation CT detector modules, such as for example volume CT (VCT) Lumex™ modules available from General Electric Company. These features enable the sharing of many existing VCT data acquisition system (DAS) solutions and technologies leading to significant cost savings for future CdTe-based and CZT-based VCT scanners.  
         [0028]      FIG. 4  further illustrates an exemplary embodiment of the CT detector module  200 . The CT detector module  200  includes a substrate  210 , which may be ceramic or metallic, having a feed through slot  225 , anti-scatter collimator plates  245 , alignment pins  240  and mounting pads  230  for proper mating to the collimator rails  118 , and a CT detector pack  205 , such as a CdTe pack or a CZT pack for example, disposed between an insulative and conductive cathode  250  and a pitch adapter  260  and ball grid array (BGA)  235 .  
         [0029]     The feed through slot  225  (better illustrated in  FIG. 5 ) allows for a plurality of flexible conductors  220 , such as flex cables for example, to pass through the substrate and provide an electrical connection between the BGA  235  and a printed circuit board (PCB)  215 .  
         [0030]     The mounting pads  230  and alignment pins  240 , which may be attached or integral to an end of the substrate  210 , are further illustrated in  FIGS. 6-9 .  FIGS. 6 and 7  depict the CT detector module  200  before installation while  FIGS. 8 and 9  depict the CT detector module  200  installed on the collimator rails  118 . The pad  230  height, shown as dimension “h” in  FIG. 9 , assures proper separation, shown as gap “g” in  FIG. 9 , of the detector cathode  250  from the collimator plates  245 . The mounting pads  230  further include a hole  285  which is precisely machined into each of the pads  230  which together with the alignment pins  240  provide a dual alignment feature and proper mating to the collimator rails  118  and CT system  100 . Module attachment to the collimator rails  118  remains as a common interface, wherein bolts are inserted through the collimator rails  118 , passing through the mounting pads  230  and the substrate  210 , secured into a threaded block  275 , which is disposed below the substrate, thus allowing for interchangeability between DC detector modules and scintillation modules.  
         [0031]     The CT detector module  200  further includes a high voltage (HV) strip  270 , as depicted in  FIGS. 8 and 9 . A common high voltage strip  270  with suitable spaced contact points is fastened to one of the collimator rails  118 . On each detector module  200  an elastomer  265  with a central conducting contact is fitted into the mounting pad  230 . On each detector module  200  a HV line  255  is used to connect between the CdTe or CZT cathode  250  and the elastomer conducting contact  265 . The presented arrangement of the HV elastomer  265  and the HV line  255  allows for a high voltage anode signal to be provided to each detector module  200  when it is fitted and pressed (forming a press fit electrical connection) on to the collimator rail  118 .  
         [0032]     A signal connection feature is further embodied wherein two opposing flexible conductors  220 , as shown in  FIG. 4 , are fastened to the substrate  210  at points  222 . BGA  235  contacts on different types of detector packs (for example CdTe, CZT, or VCT Lumex™) are precisely positioned relative to the alignment pins  240  and fastened to the flexible conductors  220  which are connected to transfer electrical signals to the printed circuit board  215 .  
         [0033]      FIG. 10  illustrates an alternative embodiment of a CT detector module  200 ′ (printed circuit board  215  not shown for clarity) wherein the flexible conductors  220  are replaced by a printed circuit board, hereinafter referred to as an Interface Adapting Board (IAB)  221 , and an electrical connector  231  (illustrated in  FIGS. 11 and 12 ), which may be an 120-pin 0.5 mm pitch connector for example. The Interface Adapting Board  221  and the electrical connector  231  provide for an electrical connection, through the feed through slot  225 , between the BGA  235  and the printed circuit board  215  as illustrated in  FIG. 10  (substrate  215  not shown). The Interface Adapting Board  221  is secured to the substrate  210  at a plurality of IAB fastener locations  223 . The Interface Adapter Board  221  also includes a pair of holes  227  that engage with a pair of IAB alignment pins  224  attached to the substrate  210 , which provides for proper alignment of the electrical connector  231 . The Interface Adapting Board  221  further includes an orientation phase mark  226  (illustrated in  FIGS. 10 and 12 ), which may be a chamfered corner for example, which provides for proper orientation of the electrical connector  231 .  
         [0034]     Exemplary embodiments of the CT detector module  200  and  200 ′ provide innovative solutions for mating generic detector packs (such as CdTe or CZT) onto a current platform (for example VCT Lumex™) that shares many components and interfaces. Some embodiments of the invention may include some of the following advantages: (1) the feed through slot  225  allows the use of available module substrate  210  pieces while maintaining short routing to printed circuit board  215 ; (2) the integrated high voltage elastomer  265  feed through provides simple bias voltage connection to the cathodes  250  that connect automatically when CT detector module  200  is mounted/pressed on to the collimator rails  118 ; and (3) high precision placement of the high voltage cathode connections.  
         [0035]     While the invention has been described with reference to a preferred embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims.