The subject matter disclosed herein generally relates to X-ray imaging systems. More specifically, the subject matter relates to systems and methods for determining X-ray exposure parameters.
X-ray systems, such as digital radiography (RAD) systems, mammography systems, computed tomography systems, and the like are used to generate images showing internal features of a subject. In the medical context, such systems are used for viewing internal anatomies and tissues, such as for diagnostic purposes. In modern projection X-ray systems, for example, X-rays are generated by an X-ray source and are directed towards a patient or other subject. The X-rays transfer through the subject, and are absorbed or attenuated by internal features. The resulting X-rays impact a digital detector where image data is generated. Collecting the image data allows for reconstruction of a useful image. Similar techniques are used for mammography, computed tomography, fluoroscopy and tomosynthesis image generation.
It is a general goal in radiography to acquire sufficient image data for reconstruction of a useful image, while optimizing, and often minimizing the dosage of radiation to the patient. Various techniques have been developed for estimating or controlling the imaging process to obtain these goals. The exposure parameters, e.g., peak kilovoltage and milliampere second values, that define the X-ray beam generated by the X-ray source directed towards the patient are normally either determined manually by default protocol selection or further adjusted by an operator. Exposure time could also be controlled by a computing device using, for example, automatic exposure control (AEC) methods.
The technique of manual determination employs a fixed time exposure using parameters manually defined by the operator, and as such is very dependent on operator skill and on the subjective estimation of the exposure needed to realize a clinically useful image and image quality. However, manual methods often generate low quality images (e.g., images with low signal to noise ratio), precisely because the determination of the exposure parameters is subjective. Further, in addition to producing low quality images that often require a retake, the manual method can result in over-exposure of the area or region of interest (ROI) within the patient. In either situation, or when both situations occur, the result is an unnecessary increase of the radiation dose to the patient, which is highly undesirable.
In an attempt to minimize the radiation dose to a patient, with regard to the operation of ACE systems and methods, a computing device controls the exposure parameters based on information received from sensors in the form of one or more dose sensors, such as ion or ionization chambers or solid-state sensors, coupled with the X-ray detector which measure radiation exposure. Current digital radiography systems using AEC or photo-timing to control exposure (and consequently dose) to the patient rely on proper alignment of patient anatomy with respect to fixed locations on the digital RAD system, i.e., the positions on the detector where the sensors/ionization chambers are located.
Problems arise, however, in situations where it is difficult to align body parts with the fixed locations on the system, especially when these fixed locations or sensors are not properly adapted to the patient anatomies, patient sizes, and so forth. By way of example, pediatric imaging is especially challenging because it is often difficult to align smaller body parts with the ion chambers of the imaging system. Extremity imaging, both adult and pediatric, faces similar challenges. Because the exposure measurement devices, such as ion chambers, serve as integrators of received radiation, misalignment of the anatomy being imaged relative to the ionization chambers/sensors may result in under or over-estimating the radiation actually applied to the anatomy or region of interest (ROI).
Further, certain radiography and digital radiography (RAD) systems, such as mobile RAD systems, cannot employ AEC systems and methods due to the lack of ionization chambers associated with the detector in these mobile RAD systems.
In addition, on many occasions the RAD system is utilized to obtain multiple images of a patient anatomy that are subsequently stitched or pasted together, i.e., an image pasting process, in order to form a larger image for diagnostic purposes. The differences in the shape of the different portions of the anatomy to be imaged create difficulties with regard to the alignment of those different portions of the anatomy with the sensors/ionization chambers utilized with AEC systems and methods, such as described previously.
Further, due to a thickness variation across different portions of anatomy being imaged, it is not optimal to use a single fixed technique for all acquisitions due to the differences between the ROIs, i.e., the thickness of the ROIs and/or the surrounding tissues across the anatomy being imaged. To avoid dose variation to the ROIs, typically AEC is used in order to determine the exposure parameters for the ROIs. However, AEC sensors have fixed locations which are often shifted from the positions of the ROIs in the various portions of the anatomy being imaged, such as shown in
As an alternative to either manual or AEC systems and methods for exposure optimization, the use of a preliminary low dose X-ray image, i.e., a preshot, can be utilized to determine the imaging parameters. One of advantages with preshot is the automatic identification of anatomical area or area or region of interest (ROI) in anatomy on the image from the preshot. Then, based on signal estimated from those regions of the detector in alignment with the ROI, an appropriate technique and/or imaging parameters can be set for main shot/X-ray image to achieve desired dose level and image quality for main shot image. One example of a suitable process of this type is disclosed in U.S. Pat. No. 6,795,526, entitled Automatic Exposure Control For A Digital Image Acquisition System, the entirety of which is expressly incorporated by reference herein for all purposes.
However, due to the short time between exposures in RAD systems, and in particular regard to the timing of the images obtained in the process of image pasting performed with RAD systems required to minimize movement of the patient between images, the ability to use prior art preshot techniques in image pasting processes on RAD systems is not applicable.
Therefore, with regard to each of the aforementioned shortcomings of prior art imaging systems concerning the ability of those imaging systems to detect ROIs and provide exposure parameters for effective imaging of the ROIs in image pasting processes performed on RAD systems, it is desirable to develop an improved system and method for the detecting the ROIs and providing appropriate exposure parameters with the speed necessary to accommodate an image pasting process on a RAD system.
According to one aspect of an exemplary embodiment of the disclosure, a method for determining the location of one or more regions of interest (ROIs) within one or more preshot images taken of an anatomy includes the steps of providing an imaging system having a radiation source, a detector alignable with the radiation source, the detector having a support on or against which a subject to be imaged is adapted to be positioned, a camera aligned with the detector, a control processing unit operably connected to the radiation source and detector to generate image data in an imaging procedure performed by the imaging system, and to the camera to generate camera images, the controller including a central processing unit and interconnected database for processing the image data from the detector to create preshot images, a display operably connected to the controller for presenting information to a user, and a user interface operably connected to the control processing unit to enable user input to the control processing unit, positioning the subject between the radiation source and the detector, operating the radiation source and detector to generate one or more preshot images, operating the camera to generate a camera image, determining a location of an ROI within at least one of the camera image and the one or more preshot images, and adjusting exposure parameters for the operation of the radiation source to obtain one or more main shots of the subject corresponding to the image data for the ROI from the one or more preshot images.
According to another aspect of an exemplary embodiment of the disclosure, a radiography imaging system includes a radiation source, a detector alignable with the radiation source, a camera alignable with the detector, a control processing unit operably connected to the radiation source, the detector and the camera to generate image data and camera images, the control processing unit including image processing circuitry and an interconnected database for processing the image data from the detector, a display operably connected to the controller for presenting information to a user and a user interface operably connected to the controller to enable user input to the controller, wherein the image processing circuitry is configured to determine a location of an ROI within at least one of the camera image and the one or more preshot images of a subject, and to adjust exposure parameters for the operation of the radiation source to obtain one or more main shots of the subject corresponding to the image data for the ROI from the one or more preshot images.
These and other exemplary aspects, features and advantages of the invention will be made apparent from the following detailed description taken together with the drawing figures.
These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings that illustrate the best mode currently contemplated of practicing the present disclosure and in which like characters represent like parts throughout the drawings, wherein:
One or more specific embodiments will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
When introducing elements of various embodiments of the present invention, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Furthermore, any numerical examples in the following discussion are intended to be non-limiting, and thus additional numerical values, ranges, and percentages are within the scope of the disclosed embodiments.
As used herein, “electrically coupled”, “electrically connected”, and “electrical communication” mean that the referenced elements are directly or indirectly connected such that an electrical current may flow from one to the other. The connection may include a direct conductive connection, i.e., without an intervening capacitive, inductive or active element, an inductive connection, a capacitive connection, and/or any other suitable electrical connection. Intervening components may be present.
Referring to
A control processing system/processing unit/processor 26 is coupled to both the radiation source 18 and the detector 24. In general, this system 26 allows for regulation of operation of both the source 18 and the detector 24, and permits collection of information from the detector 24 for reconstruction of useful images. In the illustrated embodiment, for example, the control and processing unit/system 26 includes system control and image processing circuitry 28. Such circuitry 28 will typically include a programmed processor, supporting memory/database 29, specific applications executed by the processor during operation, which may be stored in memory/dataset 29 along with executable instructions for the operation of the control processing unit 26, and so forth. The circuitry 28 will be coupled to X-ray source control circuitry 30 that itself allows for control of operation of the X-ray source 18. The X-ray source control circuitry 30 may, for example, under the direction of the system control and image data processing circuitry 28, regulate the current and voltage applied to the X-ray source 18, alter the configuration of the collimator 20, trigger the generation of X-rays from the source 18, trigger startup and shutdown sequences of the source, and so forth.
The system control and image data processing circuitry/processing unit/processor 28 is further coupled to detector interface circuitry 32. This circuitry 32 allows for enabling the digital detector 24, and for collecting data from the digital detector 24. As will be appreciated by those skilled in the art, various designs and operations of such detectors 24 and detector interface circuitry 32 are known and are presently in use. Such designs will typically include detectors 24 having an array of discrete pixel elements defined by solid state switches and photodiodes. The impacting radiation affects the charge of the photodiodes, and the switches allow for collection of data/information regarding the impacting radiation (e.g., depletion of charge of the photodiodes). The data/information may then be processed to develop detailed images in which gray levels or other features of individual pixels in an image are indicative of the radiation impacting corresponding regions of the detector 24.
The control processing unit 26 is also illustrated as including an operator workstation interface 34. This interface allows for interaction by an operator who will typically provide inputs through an operator interface computer 36. The operator interface computer 36 and/or the system control and image data processing circuitry 28 may perform filtering functions, control functions, image reconstruction functions, and so forth. One or more input devices 38 are coupled to the operator interface computer 36, such as a keyboard, a stylus, a computer mouse, combinations thereof, among other suitable devices. The operator interface computer 36 is further coupled to a display or monitor 40 on which images may be displayed, instructions may be provided, regions of interest (ROIs) may be defined as discussed below, and so forth. In general, the operator interface computer 36 may include memory and programs sufficient for displaying the desired images, and for performing certain manipulative functions, in particular the definition of a region of interest (ROI) for image exposure control.
It should be noted that, while through the present discussion reference is made to an X-ray system 10 in the medical diagnostic context, the present invention is not so limited. For example, the invention may be used for other radiological applications, such as fluoroscopy, computed tomography, tomosynthesis and so forth. The system 10 may be used in other application contexts as well, such as part and parcel inspection, screening and so forth. Moreover, in certain contexts, and certain aspects of the detectors may be used with non-digital detectors, such as conventional film.
The system illustrated in
Additionally, the steps 304-308 can be performed individually for each preshot 48,50,52 to be obtained, or can be performed collectively, e.g., all three preshots 48,50,52 being taken in step 304 prior to sending the image data to the image data processing circuitry 28 in step 306.
After determination of the updated technique/exposure parameters optimized for the ROI(s) 56, the image data processing circuitry 28 outputs this updated technique to the control and processing system 26 in step 310. This updated technique/exposure parameters are then employed by the control and processing system 26 in step 312 to obtain the main shot image(s). After obtaining the main shot image(s) in step 312, the method 300 can terminate, or can reset to step 302 to prepare to obtain another set of one or more preshots 48,50,52.
With regard to the steps 308 and 310 of the method 300, after the determination of the location and form, e.g., shape and thickness, of the ROIs 56,70 in the preshot images 48,50,52, the image data processing circuitry 28 can optimize the parameters and/or technique for the main shot images to be taken corresponding to the preshot images 48,50,52 including each of the ROIs 56,70. The optimization of the parameters and technique based on the data from the preshot images 48,50,52 can include, but is not limited to kVp, mA, ms, filter, and the FOV for each corresponding main shot, with the image data processing circuitry 28 configured to automatically adjust any one or more of these parameters.
Referring now to
In order to determine the optimized exposure parameters for one or more regions of interest (ROI) 56 on the subject 14 according to step 308 in the method 300, in one exemplary embodiment, as an integral part of step 306 or as a separate step 307 (
In an alternative embodiment, as opposed to registering the camera image 46 to the preshot images 48,50,52/pasted image 54, or in addition to the registration, the camera image 46 can be presented as an overlay directly on the preshot images 48,50,52/pasted image 54 for identification of the ROI(s) 56.
With regard to the manner in which the ROI(s) 56 are identified on the images 46,54 in step 306/307, referring now to
After or simultaneously with the designation of the point(s) 58 and/or area(s) 60 in the camera image 46 by the operator, the point(s) 58 and/or area(s) 60 can be applied to the preshot images 48,50,52/pasted image 54 as shown in
In addition, as best shown in
After the designation of the point(s) 58 and/or area(s) 60 in the above manner constituting an exemplary embodiment of step 306/307, the image data processing circuitry 28 can then determine in step 308 the optimal exposure parameter/imaging technique for the selected the point(s) 58 and/or area(s) 60 for use in updating the technique in step 310 and obtaining the main shot of the point(s) 58 and/or area(s) 60 in step 312.
Further, while the altered or updated preshot images 48,50,52/pasted image 54 including the designated point(s) 58 and/or area(s) 60
Referring now to
In addition, in another exemplary embodiment, for an anatomy or imaging procedure that includes a symmetrical anatomy, such as shown in
Looking now at
With reference now to
With the camera image 46 as shown schematically in
In one exemplary embodiment of the system and process or method in which the image data processing circuitry 28 can automatically identify the ROIs 56,70 in the preshot images 48,50,52/pasted image 54, referring now to
In a particular exemplary embodiment of the structure and operation of the AI model 100 in
According to another exemplary embodiment of the ROIs 56,70 can be dynamically segmented/identified per anatomy/view change during image pasting and other imaging procedures performed utilizing the imaging system 10 including the image data processing circuitry 28 and/or AI model 100. Further, the image data processing circuitry 28 and/or AI model 100 can be combined with a traditional segmentation methods to cover all applications for use of the system 10 including the image data processing circuitry 28 and/or AI model 100, including both dual energy and single energy imaging applications.
Finally, it is also to be understood that the system 10 may include the necessary electronics, software, memory, storage, databases, firmware, logic/state machines, microprocessors, communication links, displays or other visual or audio user interfaces, printing devices, and any other input/output interfaces to perform the functions described herein and/or to achieve the results described herein. For example, as previously mentioned, the system may include at least one processor and system memory/data storage structures, which may include random access memory (RAM) and read-only memory (ROM). The at least one processor of the system 10 may include one or more conventional microprocessors and one or more supplementary co-processors such as math co-processors or the like. The data storage structures discussed herein may include an appropriate combination of magnetic, optical and/or semiconductor memory, and may include, for example, RAM, ROM, flash drive, an optical disc such as a compact disc and/or a hard disk or drive.
Additionally, a software application that adapts the controller to perform the methods disclosed herein may be read into a main memory of the at least one processor from a computer-readable medium. The term “computer-readable medium”, as used herein, refers to any medium that provides or participates in providing instructions to the at least one processor of the system 10 (or any other processor of a device described herein) for execution. Such a medium may take many forms, including but not limited to, non-volatile media and volatile media. Non-volatile media include, for example, optical, magnetic, or opto-magnetic disks, such as memory. Volatile media include dynamic random access memory (DRAM), which typically constitutes the main memory. Common forms of computer-readable media include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, any other magnetic medium, a CD-ROM, DVD, any other optical medium, a RAM, a PROM, an EPROM or EEPROM (electronically erasable programmable read-only memory), a FLASH-EEPROM, any other memory chip or cartridge, or any other medium from which a computer can read.
While in embodiments, the execution of sequences of instructions in the software application causes at least one processor to perform the methods/processes described herein, hard-wired circuitry may be used in place of, or in combination with, software instructions for implementation of the methods/processes of the present invention. Therefore, embodiments of the present invention are not limited to any specific combination of hardware and/or software.
It is understood that the aforementioned compositions, apparatuses and methods of this disclosure are not limited to the particular embodiments and methodology, as these may vary. It is also understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only, and is not intended to limit the scope of the present disclosure which will be limited only by the appended claims.