Abstract:
A method and apparatus for digital radiography is provided. The method includes the steps of: a) providing an apparatus that includes an X-ray generator operable to generate and project X-rays, and a digital X-ray sensor operable to receive X-rays projected by the X-ray generator; b) determining whether the X-ray sensor is in an operable mode, or a non-operable mode; c) using the X-ray generator to project X-rays through a subject target area if the X-ray sensor is in the operable mode, or to prevent the generator from projecting X-rays through the subject target area if the X-ray sensor is in the non-operable mode; and d) using the X-ray sensor to receive the projected X-rays after they have transversed the subject target area if the X-ray sensor is in the operable mode.

Description:
[0001]    This application claims the benefit of U.S. Patent Application Ser. No. 61/599,187, filed Feb. 15, 2012, which is hereby incorporated by reference into the present application in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Technical Field 
         [0003]    The present invention relates to methods and apparatuses for digital radiography in general, and to control techniques for digital radiography in particular. 
         [0004]    2. Background Information 
         [0005]    Digital radiography is an X-ray imaging technique in which digital X-ray sensors are used instead of traditional photographic film. Digital radiography may be preferred over traditional radiography because it eliminates the need for chemical processing of photographic film, it is more time efficient, and it enables digital transfer and enhancement of X-ray images. Digital radiography may be problematic, however, in that digital X-ray sensors are subject to inoperability; e.g., inoperability caused by hardware failure, battery failure, or absence of the digital X-ray sensor. Inoperability of a digital X-ray sensor is often not discovered until after digital radiography has been attempted. For example, in a common scenario, the digital radiography technician unsuccessfully attempts to image a patient, and discovers the inoperability of the digital X-ray sensor only after the patient has been irradiated with X-rays. Inoperability of a digital X-ray sensor is problematic, therefore, in that it can result in unnecessary irradiation of the patient with X-rays, which may be harmful to the patient in large doses. Inoperability of a digital X-ray sensor is also problematic because it causes lost practice and patient time, lost practice revenue, patient unhappiness and worry, and patient loss of confidence. 
         [0006]    What is needed, therefore, is an improved apparatus and method for digital radiography, which apparatus and method prevents unnecessary irradiation of the patient with X-rays as result of digital X-ray sensor inoperability. 
       SUMMARY OF THE INVENTION 
       [0007]    According to an aspect of the present invention, an apparatus for digital radiography is provided that includes an X-ray generator operable to generate and project X-rays, and a digital X-ray sensor operable to receive X-rays projected by the X-ray generator. The X-ray generator and the X-ray sensor are operable to determine whether the apparatus is in an inoperable mode or an operable mode by communications between the X-ray sensor and the X-ray generator. 
         [0008]    According to another aspect of the present invention, a method for digital radiography is provided. The method includes the steps of: a) providing an apparatus that includes an X-ray generator operable to generate and project X-rays, and a digital X-ray sensor operable to receive X-rays projected by the X-ray generator; b) determining whether the X-ray sensor is in an operable mode, or a non-operable mode; c) using the X-ray generator to project X-rays through a subject target area if the X-ray sensor is in the operable mode, or to prevent the generator from projecting X-rays through the subject target area if the X-ray sensor is in the non-operable mode; and d) using the X-ray sensor to receive the projected X-rays after they have transversed the subject target area if the X-ray sensor is in the operable mode. 
         [0009]    The present apparatus and method, and advantages associated therewith, will become more readily apparent in view of the detailed description provided below, including the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a schematic view of the present apparatus. 
           [0011]      FIG. 2  is a block diagram of steps that may be implemented using the present method. 
       
    
    
     DESCRIPTION OF THE INVENTION 
       [0012]    Referring to  FIG. 1 , the present invention provides an apparatus  8  and method for digital radiography. The apparatus  8  comprises an X-ray generator  10  and a digital X-ray sensor  12 . 
         [0013]    The X-ray generator  10  (an embodiment of which is shown schematically in  FIG. 1 ) includes hardware (e.g., an X-ray tube, a collimator, etc.) that is operable to generate and project X-rays. The X-ray generator  10  also includes a processor  14 , a transmitter  16  and a receiver  18 . The processor  14  is in electronic communication with, and is operable to control, the hardware, the transmitter  16  and the receiver  18 . The transmitter  16  and receiver  18  are operable to transmit and receive signals to and from the X-ray sensor  12 , respectively, as discussed below. 
         [0014]    The X-ray sensor  12  (an embodiment of which is shown schematically in  FIG. 1 ) shown is operable to receive X-rays projected by the X-ray generator  10 . The X-ray sensor  12  may be characterized as a flat panel detector or a high-density line-scan detector, which terms are known in the art. In the exemplary embodiment shown in  FIG. 1 , the X-ray sensor  12  includes an X-ray detector plate  20 , an image scanner  22 , a processor  24 , a transmitter  26 , a receiver  28 , and a battery  30 . The X-ray detector plate  20  contains a material (e.g., silicon), which generates photoelectrons in response to X-rays received from the X-ray generator  10 . The image scanner  22  is operable to detect the photoelectrons generated by the X-ray detector plate  20 , and create image data there from. The processor  24  is in electronic communication with, and is operable to control, the X-ray detector plate  20 , the image scanner  22 , the transmitter  26 , the receiver  28 , and the battery  30 . The transmitter  26  and receiver  28  are operable to transmit and receive signals (e.g., image data) to and from the X-ray generator  10 , respectively, as discussed below. The battery  30  provides the electricity required to power the X-ray detector plate  20 , the image scanner, the processor  24 , the transmitter  26 , and the receiver  28 . 
         [0015]    The X-ray generator  10  and the X-ray sensor  12  are in communication with one another (which communication paths  32  are diagrammatically shown as dashed lines in  FIG. 1 ). The X-ray generator transmitter  16  is operable to transmit communications to the X-ray sensor  12 , and the X-ray sensor receiver  28  is operable to receive said communications. Similarly, the X-ray sensor transmitter  26  is operable to transmit communications to the X-ray generator  10 , and the X-ray generator receiver  18  is operable to receive the communications. The communications between the transmitters  16 ,  26  and receivers  18 ,  28  of the X-ray generator  10  and the X-ray sensor  12  may be via wired or wireless connections. In embodiments in which the communications between the transmitters  16 ,  26  and receivers  18 ,  28  of the X-ray generator  10  and the X-ray sensor  12  are via wireless connections, the communications may be radio-frequency communications. The radio-frequency communications may be band-limited so as to prevent interference with other devices in close proximity to the apparatus  8 . The apparatus  8  may alternatively or additionally be configured so that the radio-frequency communications are distance-limited (i.e., prevented from travelling more than a predetermined distance from the apparatus  8 ). 
         [0016]    The X-ray generator  10  and the X-ray sensor  12  are operable to communicate with one another to confirm the operability of the X-ray sensor  12 ; i.e. if the apparatus is in an inoperable mode or an operable mode. The X-ray sensor  12  may be deemed to be in an operable mode if the battery  30  is providing sufficient electricity to power the X-ray detector plate  20 , the image scanner  22 , the processor  24 , the transmitter  26 , and the receiver  28 . The X-ray sensor  12  may be deemed to be in an operable mode if the X-ray sensor processor  24  is internally in normal electronic communication and is in control of the X-ray detector plate  20 , the image scanner  22 , the transmitter  26 , the receiver  28 , and the battery  30 . The X-ray sensor  12  may be deemed to be in an operable mode if the X-ray sensor  12  is within a particular distance from the X-ray generator  10 . The X-ray sensor  12  may be deemed to be in an operable mode if the identity of the X-ray sensor  12  is known to the X-ray generator  10 ; e.g., if an identifier (e.g., an identity code) associated with the X-ray sensor  12  matches an identifier stored in the X-ray generator  10 . The X-ray sensor (and therefore the apparatus  8 ) may be determined to be inoperable, conversely, if any of the above parameters are not true; e.g. if the X-ray sensor  12  is not internally in normal electronic communication, and/or if the X-ray sensor  12  is outside a particular distance from the X-ray generator  10 , and/or if the identity of the X-ray sensor  12  is not known to the X-ray generator  10 , etc. In addition, the apparatus  8  may be determined to be in an inoperable mode by the X-ray sensor  12  communicating to the X-ray generator  10  that the X-ray sensor  12  is located at a position relative to the X-ray generator  10  wherein the X-ray sensor  12  is unable to receive X-rays projected by the X-ray generator  10  in an amount sufficient transverse a subject target area and create a clinically usable image. 
         [0017]    The X-ray generator transmitter  16  is operable to send, and the X-ray sensor receiver  28  is operable to receive, communications requesting that the X-ray sensor  12  confirm the operability of the X-ray sensor  12 . Such communications are processed by the X-ray sensor processor  24 , and the X-ray sensor processor  24  may execute protocols stored in memory to determine the operability of the X-ray sensor  12 ; e.g., protocols within the X-ray sensor  12  may determine (as indicated above) if internal communications within the X-ray are acceptable, if the X-ray sensor  12  is within a particular distance from the X-ray generator  10 , etc. Communications indicating the operability of the X-ray sensor  12  are transmitted by the X-ray sensor transmitter  26 , and are received by the X-ray generator receiver  18 . If the communications indicate that the X-ray sensor  12  is inoperable, the X-ray generator  10  may be prevented (e.g., by a safety controller, or by protocols executed by the X-ray generator processor  14 ) from generating and projecting X-rays  34 . The X-ray generator  10  may be prevented from generating and projecting X-rays  34  until the X-ray generator  10  receives communications from the X-ray sensor  12  indicating that the X-ray sensor  12  is operable. The digital radiography technician may be notified of the inoperability of the X-ray sensor  12  by visual or audible warning, which may for example be generated by a display or indicator on the X-ray generator  10 . This feature prevents unnecessary exposure of patient to X-rays  34  as a result of X-ray sensor  12  inoperability. This feature can be performed quickly (e.g., in one second or less), and thus will not cause disruption to the use of the apparatus  8  when the X-ray sensor  12  is confirmed to be operable. 
         [0018]    In some embodiments, the X-ray sensor  12  may be configured to continuously transmit a radio-frequency communication with an identifier (e.g., an ID code) when it is operable. The X-ray generator  10  may be configured to check to make sure that X-ray sensor  12  is generating the radio-frequency communication before it is used to generate and project X-rays. If the X-ray generator  10  does not detect the radio-frequency communication, the X-ray generator  10  will be prevented from generating and projecting X-rays  34 , as discussed above. 
         [0019]    In some embodiments, the X-ray sensor may be adapted to be mounted in a reader which can communicate with the X-ray sensor and also communicate with the X-ray generator, or other device, via wired or wireless communications. 
         [0020]    Since an X-ray generator  10  may also be used with X-ray film as well as digital X-ray sensors  12 , in some embodiments the X-ray generator  10  may include an override switch to change to a film mode in which case the communication between the X-ray sensor  12  and X-generator  10  is not required for generation of X-rays. In these embodiments, the apparatus  8  preferably includes a means for communicating with a cassette holding the X-ray film. The communications between the X-ray generator and the cassette may operate in a manner similar to that described between the X-ray generator  10  and the X-ray sensor  12 . 
         [0021]    Now referring to  FIGS. 1 and 2 , the present invention also provides a method for digital radiography. The first step of the method involves providing an apparatus  8  that includes an X-ray generator  10  operable to generate and project X-rays  34 , and a digital X-ray sensor  12  operable to receive X-rays  34  projected by the X-ray generator  10 . For ease of description, the method will be described as being performed using the apparatus  8  described above. The method is not limited to use with this apparatus, however. 
         [0022]    The second step involves confirming the operability of the X-ray sensor  12 . This step may be performed as described above; e.g., the X-ray generator transmitter  16  may send, and the X-ray sensor receiver  28  may receive, communications requesting that the X-ray sensor  12  confirm the operability of the X-ray sensor  12 , etc. In one example, the operability of the X-ray sensor  12  is confirmed, for example, by checking to make sure that the battery  30  is providing sufficient electricity to power the X-ray detector plate  20 , the image scanner  22 , the processor  24 , the transmitter  26 , and the receiver  28 . If the battery  30  is providing insufficient electricity, this may be detected by the absence of a signal transmitted from the X-ray sensor  12  to the X-ray generator  10 . Alternatively, the X-ray sensor  12  may continuously or periodically transmit a battery voltage measurement to the X-ray generator  10  for processing. This alternative approach may be preferred, as it allows the digital radiography technician to replace the battery  30  prior to failure. In another example, the operability of the X-ray sensor  12  may be confirmed by checking to make sure the X-ray sensor  12  is proximate to the X-ray generator  10 ; i.e., checking to make sure the X-ray sensor  12  is present and not, for example, outside of operable range (e.g., in another room). The X-ray generator  10  may check the proximity of the X-ray sensor  12  by detecting the presence of, and/or measuring the strength of, distance-limited radio-frequency communications transmitted by the X-ray sensor  12 . The X-ray generator  10  may additionally or alternatively be configured to check the proximity of the X-ray sensor  12  to a desired position; e.g., a position such as the examination chair/table on which the patient is positioned during digital radiography. The X-ray sensor  12  and/or the X-ray generator  10  may also include directional antenna that are operable to ensure that the X-ray sensor  12  is not only proximate to the X-ray generator  10 , but also correctly positioned relative thereto; e.g., the directional antenna may enable the X-ray generator  10  to confirm that the X-ray sensor  12  is within the path of the X-rays projected by the X-ray generator  10 . In yet another example, the operability of the X-ray sensor  12  is confirmed by checking to make sure that a digital identity of the X-ray sensor  12  matches an identifier stored within the X-ray generator  10 . This ensures that the X-ray generator  10  does not generate and project X-rays onto an unintended X-ray sensor  12  (e.g., an X-ray sensor  12  in use in an adjacent room). 
         [0023]    The third step involves using the X-ray generator  10  to generate and project X-rays  34  through a subject target area. This step may be controlled by the X-ray generator processor  14 , as described above. 
         [0024]    The fourth step involves using the X-ray sensor  12  to receive the projected X-rays  34  after they have transversed the subject target area. This step may be controlled by the X-ray sensor processor  24 , as described above. 
         [0025]    While the invention has been described with reference to an exemplary embodiment, 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(s) disclosed herein as the best mode contemplated for carrying out this invention.