The subject matter disclosed herein relates to X-ray imaging systems and more particularly to X-ray imaging systems using digital detectors having photovoltaic devices.
The advent of digital X-ray detectors has brought enhanced workflow and high image quality to medical imaging. However, many of the earlier radiographic imaging systems employ conventional X-ray imaging using film as the X-ray detection media. In order to obtain images from these systems, the imaging medium must be transported and processed after each exposure, resulting in a time delay in obtaining the desired images. Digital radiography provides an alternative that allows the acquisition of image data and reconstructed images on the spot for quicker viewing and diagnosis, and allows for images to be readily stored and transmitted to consulting and referring physicians and specialists. However, the cost of replacing the earlier conventional radiographic imaging systems with digital radiographic imaging systems may be imposing to a hospital or tertiary care medical center. Hence, there is a need to retrofit the earlier radiographic imaging systems for digital radiography in a cost effective manner involving as few components of the systems as possible.
In accordance with a first embodiment, an X-ray imaging system is provided. The X-ray imaging system includes an X-ray radiation source. The X-ray imaging system also includes a source controller coupled to the source and configured to command emission of X-rays for image exposures. The X-ray imaging system further includes a digital X-ray detector configured to acquire X-ray image data without communication from the source controller, wherein the digital X-ray detector includes a photovoltaic device, and the digital X-ray detector is configured to determine one or more of a beginning, end, or duration of an image exposure via the photovoltaic device.
In accordance with a second embodiment, a digital X-ray detector is provided. The detector includes circuitry configured to acquire X-ray image data without communication from an X-ray source controller. The detector also includes a photovoltaic device, wherein the circuitry is configured to determine one or more of a beginning, end, or duration of an image exposure via the photovoltaic device.
In accordance with a third embodiment, an X-ray imaging method is provided. The method includes monitoring a voltage or current level of a photovoltaic device of a digital X-ray detector. The method also includes commanding an X-ray radiation source to perform an X-ray exposure via a source controller coupled to the source, the source controller not being in communication with the X-ray detector. The method further includes determining one or more of a beginning, end, or duration of the X-ray exposure based on the voltage level of the photovoltaic device.
These and other features, aspects, and advantages of the present subject matter will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
Referring generally to
In the embodiment illustrated in
In one embodiment, the imaging system 12 may be used in concert with one or both of a patient table 28 and a wall stand 30 to facilitate image acquisition. Particularly, the table 28 and the wall stand 30 may be configured to receive detector 22. For instance, detector 22 may be placed on an upper, lower or intermediate surface of the table 28, and the patient 20 (more specifically, an anatomy of interest of the patient 20) may be positioned on the table 28 between the detector 22 and the radiation source 16. Also, the wall stand 30 may include a receiving structure 32 also adapted to receive the detector 22, and the patient 20 may be positioned adjacent the wall stand 30 to enable the image data to be acquired via the detector 22. The receiving structure 32 may be moved vertically along the wall stand 30.
Also depicted in
The portable detector control device 40 is also configured to communicate instructions (e.g., detector operating mode) to the detector 22 for the acquisition of X-ray image data. In turn, the detector 22 is configured to prepare for an X-ray exposure in response to instructions from the portable detector control device 40, and to transmit a detector ready signal to the device 40 indicating that the detector 22 is prepared to receive the X-ray exposure. The device 40 may also be configured to communicate patient information or X-ray technique information to the detector 22. Similar to the detector 22, the device 40 may be without communication from the controller of the X-ray source 16. Further, the portable detector control device 40 is configured to receive X-ray image data from the detector 22 for processing and image reconstruction. Indeed, both the detector 22 and the portable detector control device 40 are configured to at least partially process the X-ray image data. However, in certain embodiments, the detector 22 and/or the portable detector control device 40 are configured to fully process the X-ray image data. Also, the detector 22 and/or the device 40 is configured to generate a DICOM compliant data file based upon the X-ray image data, patient information, and other information. Further, the detector 22 and/or the device 40 is configured to wirelessly transmit (or via a wired connection) processed X-ray image data (e.g., partially or fully processed X-ray image data) to an institution image review and storage system over a network 42. The institution image review and storage system may include a hospital information system (HIS), a radiology information system (RIS), and/or picture archiving communication system (PACS). In some embodiments, the institution image review and storage system may process the X-ray image data. In one embodiment, the workstation 34 may be configured to function as a server of instructions and/or content on a network 42 of the medical facility. The detector 22 and/or device 40 are also configured to transmit, via a wired or wireless connection, processed X-ray images to the printer 37 to generate a copy of the image.
The portable detector control device 40 includes a user-viewable screen 44 and is configured to display patient data and reconstructed X-ray images based upon X-ray image data on the screen 44. The screen 44 may include a touch-screen and/or input device (e.g., keyboard) configured to input data (e.g., patient data) and/or commands (e.g., to the detector). For example, the device 40 may be used to input patient information and other imaging related information (e.g., type of source 16, imaging parameters, etc.) to form a DICOM image header. In one embodiment, the patient information may be transferred from a patient database via a wireless or wired connection from the network or the workstation 34 to the device 40. The detector 22 and/or device may incorporate the information for the image header with the X-ray image to generate the DICOM compliant data file. Also, the device 40 may be used to navigate X-ray images displayed on the screen 44. Further, the device 40 may be used to modify the X-ray images, for example, by adding position markers (e.g., “L”/“R”for left and right, respectively) onto the image. In one embodiment, metal markers may be placed on the detector 22 to generate position markers.
In one embodiment, the imaging system 12 may be a stationary system disposed in a fixed X-ray imaging room, such as that generally depicted in and described above with respect to
For instance, as illustrated in the X-ray system of
The source 16 is coupled to a power supply 52 which furnishes power for examination sequences. The source 16 and power supply 52 are coupled to a source controller 54 configured to command X-ray emission of X-rays for image exposures. As mentioned above, the detector 22 is configured to acquire X-ray image data without communication from the source controller 54. Also, the detector 22 is responsive to the portable detector control device 40 configured to communicate instructions the detector 22 for acquisition of the X-ray image data. In addition, the portable detector control device 40 is configured to receive the X-ray image data from the detector 22 for processing and imaging reconstruction.
The detector 22 includes a wireless communication interface 56 for wireless communication with the device 40, as well as a wired communication interface 58, for communicating with the device 40 when it is tethered to the detector 22. The detector 22 and/or the device 40 may also be in communication with the institution image review and storage system over the network 42 via a wired or wireless connection. As mentioned above, the institution image review and storage system may include PACS 60, RIS 62, and HIS 64. In certain embodiments, the detector 22 may also communicate with components of the imaging system 12 such as the operator workstation 34 via a wired or wireless connection. It is noted that the wireless communication interface 56 may utilize any suitable wireless communication protocol, such as an ultra wideband (UWB) communication standard, a Bluetooth communication standard, or any 802.11 communication standard. Moreover, detector 22 is coupled to a detector controller 66 which coordinates the control of the various detector functions. For example, detector controller 66 may execute various signal processing and filtration functions, such as for initial adjustment of dynamic ranges, interleaving of digital image data, and so forth. The detector controller 66 is responsive to signals from the device 40. The detector controller 66 is linked to a processor 68. The processor 68, the detector controller 66, and all of the circuitry receive power from a power supply 70. The power supply 70 may include one or more batteries. Also, the processor 68 is linked to detector interface circuitry 72.
The detector 22 converts X-ray photons received on its surface to lower energy photons such as light or optical photons (e.g., via a scintillator 77). The detector 22 includes a detector array 74 (e.g., imaging panel) that includes an array of photodetectors to convert the light photons to electrical signals. In certain embodiments, the detector array 74 also includes the scintillator 77. These electrical signals are converted to digital values by the detector interface circuitry 72 which provides the values to the processor 68 to be converted to imaging data and sent to the device 40 to reconstruct an image of the features within the subject 20. In one embodiment, the detector 22 may at least partially process or fully process the imaging data. Alternatively, the imaging data may be sent from the detector 22 to a server to process the imaging data.
The processor 68 is also linked to a voltage/current measuring device 73. The voltage/current measuring device 73 is coupled to a photovoltaic device 75. The photovoltaic device 75, via the photovoltaic effect or photoconductive effect (if reverse biased), generates a voltage or current in response to optical photons and/or X-rays received, e.g., from the scintillator, on a surface of the device 75. Thus, the voltage or current of the photovoltaic device 75 may be monitored to determine the beginning, end, and/or duration of an image exposure. In certain embodiments, the voltage or current of the photovoltaic device may be monitored to control an auto-exposure control. The voltage measuring device 73 measures the voltage or current generated by the photovoltaic device 75. The voltage/current measuring device 73 may include any type of data collecting or measuring device such as an analog-to-digital converter, field-programmable gate array, and so forth. The photovoltaic device 75 may include one or more solar panels as described in greater detail below. In certain embodiments, the solar panels may include semiconductor materials reactive to X-ray or visible light spectrum. In other embodiments, the device 75 may include a semiconductor device arranged to serve a similar function as the solar panels (i.e., collect the optical photons and/or X-rays to enable determining the beginning, end, and/or duration of an image exposure).
The processor 68 is further linked to an illumination circuit 76. The detector controller 66, in response to a signal received from the device 40, may send a signal to the processor 68 to signal the illumination circuit 76 to illuminate a light 78 to indicate the detector 22 is prepared to receive an X-ray exposure in response to the signal. Indeed, in response to a signal from the device 40, the detector 22 may be turned on or awoken from an idle state. Alternatively, the detector 22 may be turned on directly or awoken from an idle state by the user (e.g., pressing an on/off button located on the detector 22). As another alternative, the detector 22 may be awoken from an idle or lower-powered state upon detecting the beginning of an exposure via the photovoltaic device 75.
Further, the processor is linked to a memory 80. The memory 80 may store various configuration parameters, calibration files, and detector identification data. In addition, the memory 80 may store patient information received from the device 40 to be combined with the image data to generate a DICOM compliant data file. Further, the memory 80 may store sampled data gathered during the imaging mode as well as X-ray images. As mentioned above, in some embodiments, the device 40 may conduct the image processing and incorporate a DICOM header to generate a DICOM compliant data file. Still further, the processor 68 is linked to a timer 82 to monitor times for multiple purposes such as determining the duration of an exposure.
In a present embodiment, detector 22 consists of a scintillator that converts X-ray photons received on the detector surface during examinations to lower energy (light) photons. An array of photodetectors then converts the light photons to electrical signals which are representative of the number of photons or the intensity of radiation impacting individual pixel regions or picture elements of the detector surface. Readout electronics convert the resulting analog signals to digital values that can be processed, stored, and displayed, such as on device 40 following reconstruction of the image. In a present form, the array of photodetectors is formed of amorphous silicon. The array of photodetectors or discrete picture elements is organized in rows and columns, with each discrete picture element consisting of a photodiode and a thin film transistor. The cathode of each diode is connected to the source of the transistor, and the anodes of all diodes are connected to a negative bias voltage. The gates of the transistors in each row are connected together and the row electrodes are connected to the scanning electronics as described below. The drains of the transistors in a column are connected together and the electrode of each column is connected to an individual channel of the readout electronics. As described in greater detail below, the detector control circuitry 84 is configured to sample data from the discrete picture elements during receipt of X-ray radiation in response to the photovoltaic device 75 detecting the beginning of the exposure and to cease sampling upon detecting the end of the exposure.
Turning back to the embodiment illustrated in
In the illustrated embodiment, row drivers 94 and readout electronics 96 are coupled to a detector panel 98 which may be subdivided into a plurality of sections 100. Each section 100 is coupled to one of the row drivers 94, and includes a number of rows. Similarly, each column driver 96 is coupled to a series of columns. The photodiode and thin film transistor arrangement mentioned above thereby define a series of pixels or discrete picture elements 102 which are arranged in rows 104 and columns 106. The rows and columns define an image matrix 108, having a height 110 and a width 112.
As also illustrated in
It should be noted that in certain systems, as the charge is restored to all the picture elements 102 in a row simultaneously by each of the associated dedicated readout channels, the readout electronics is converting the measurements from the previous row from an analog voltage to a digital value. Furthermore, the readout electronics may transfer the digital values from rows previous to the acquisition subsystem, which will perform some processing prior to displaying a diagnostic image on a monitor or writing it to film.
The circuitry used to enable the rows may be referred to in a present context as row enable or field effect transistor (FET) circuitry based upon the use of field effect transistors for such enablement (row driving). The FETs associated with the row enable circuitry described above are placed in an “on” or conducting state for enabling the rows, and are turned “off” or placed in a non-conducting state when the rows are not enabled for readout. Despite such language, it should be noted that the particular circuit components used for the row drivers and column readout electronics may vary, and the present invention is not limited to the use of FETs or any particular circuit components.
The panel support 128 includes a surface 132 (e.g., front or top surface) and a surface 134 (e.g., rear or bottom surface) disposed opposite from each other. The backscattered X-ray blocking layer 126 and motherboard 130 are disposed on or coupled to surfaces 132, 134, respectively, of the panel support 128. In particular, surface 134 of the panel support 128 is disposed on or coupled to surface 136 (e.g., front or top surface) of the motherboard 130. Also, surface 138 (e.g., rear or bottom surface) of the backscattered X-ray blocking layer 126 is disposed on or coupled to surface 132 of the panel support 128. The motherboard 130 includes a circuit board and electronics including row drivers 94 and readout electronics 96 to acquire signals from the detector array 74. The backscattered X-ray blocking layer 126 may include lead to minimize X-ray backscattering. X-rays may pass through the detector array 74 and reflect back off whatever is found behind the detector array 74 such as the electronics or panel support 128. The reflected X-rays may be detected by the scintillator layer, converted to light, and detected by the photosensitive layer in the detector elements. The backscattered X-ray blocking layer 126 may absorb the X-rays passing through the detector array 74 and any backscattered X-rays.
The photovoltaic device 75 includes a surface 140 (e.g., front or top surface) and a surface 142 (e.g., rear or bottom surface) disposed opposite from each other. The detector array 74 and backscattered X-ray blocking layer 126 are disposed on or coupled to surfaces 140, 142, respectively, of the photovoltaic device 75. In particular, surface 142 of the photovoltaic device 75 is disposed on or coupled to the surface 144 (e.g., front or top surface) of the backscattered X-ray blocking layer 126. Also, surface 146 (e.g., rear or bottom surface) of the detector array 74 is disposed on or coupled to surface 140 of the photovoltaic device 75. The photovoltaic device 75 is disposed between the detector array 74 and the backscattered X-ray blocking layer 126 so that the photovoltaic device 75 does not obstruct X-ray detection by the detector array 74.
For illustrative purposes, the photovoltaic device 75 of
As depicted in
As mentioned above, the detector 22 is without communication from the source controller 54 and, thus, is without a priori knowledge of the beginning and ending times of an exposure. In one embodiment, the detector 22 is configured to automatically determine or detect the beginning, end, and/or duration of the exposure utilizing the photovoltaic device 75 without communication from the source controller 54 and/or detector control device 40.
Upon detecting the beginning of the exposure, the processor 68 sends a signal to the timer 82 to start timing (block 166) the duration or length of the exposure. Also, in certain embodiments, upon detecting the beginning of the exposure, if the detector 22 is in an idle or low power mode prior to and during the beginning of the exposure, the detector 22 switches from the idle mode to imaging power mode (block 168).
Further, upon detecting the beginning of the exposure, the detector 22 begins sampling image data from during the exposure (block 170). During the exposure, the voltage/current measuring device 73 continues to monitor the voltage or current of the photovoltaic device 75. Once the generated voltage or current returns to pre-exposure levels, this enables the processor 68 to determine or detect the end of the exposure (block 172). Upon detecting the end of the exposure, the processor 68 sends a signal to the timer 82 to end or stop timing (block 174) the duration or length of the exposure. Upon stopping the timer 82, the processor 68 determines the duration or length of the exposure (block 176).
Also, upon detecting the end of the exposure, the detector 22 ends sampling of image data obtained during the exposure (block 178). In certain embodiments, the device 40 at least partially processes the X-ray image data. In some embodiments, the device 40 completely processes the X-ray image data. Alternatively, the device 40 acquires completely processed X-ray image data from the detector 22. In other embodiments, neither the detector 22 nor the device 40 completely process the X-ray image data, but send the X-ray image data to the institution image review and storage system for subsequent processing. In either case, to obtain an X-ray image, the sampled X-ray image data is obtained and/or combined (block 180) from one or more imaging frames. The combined data may be further processed (e.g., offset-corrected) prior to generating an X-ray image (block 182).
Upon the determining the beginning of the X-ray exposure, the detector 22 continues to monitor the voltage or current level of the photovoltaic device 75 and compares the voltage or current level obtained from the photovoltaic device 75 to the baseline voltage or current to determine if the obtained voltage or current level has returned to or fallen below the baseline voltage or current (block 196). If the obtained voltage or current level from the photovoltaic device 75 has not returned to the baseline voltage or current, this indicates that the X-ray exposure is still occurring and the detector 22 continues to sample X-ray image data (block 194). If the obtained voltage or current level from the photovoltaic device 75 does return to the baseline voltage or current, this indicates the X-ray exposure has ended and the detector 22 ends sampling image data from during the exposure (block 198). The sampled X-ray image data may then be processed (block 200) as described above.
Technical effects of the disclosed embodiments include providing systems and methods to allow for the retrofitting of conventional X-ray systems by replacing cassettes with a digital X-ray detector. In retrofitting the X-ray systems, the digital X-ray detector 22 does not communicate with the X-ray imaging system 12. Since the detector 22 does not communicate with the X-ray imaging system 12, the detector 22 lacks data indicating the timing signals for an X-ray exposure. Thus, the detector 22 utilizes the photovoltaic device 75 to monitor the beginning, end, and/or duration of the X-ray exposure.
This written description uses examples to disclose the present subject matter, including the best mode, and also to enable any person skilled in the art to practice the present approaches, including making and using any devices or systems and performing any incorporated methods. The patentable scope is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.