Patent Publication Number: US-11647976-B2

Title: Imaging systems and methods

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 15/716,099 filed Sep. 26, 2017 (now U.S. Pat. No. 11,006,921), which is a continuation of U.S. application Ser. No. 15/706,018 filed Sep. 15, 2017 (now U.S. Pat. No. 10,076,302) which claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 62/394,909, filed Sep. 15, 2016; U.S. Provisional Patent Application Ser. No. 62/394,956, filed Sep. 15, 2106; U.S. Provisional Patent Application Ser. No. 62/471,191, filed Mar. 14, 2017; and U.S. Provisional Patent Application Ser. No. 62/504,876, filed May 11, 2017; wherein the entire contents of each application is incorporated herein by reference. This application also incorporates PCT application PCT/US2017/051774 filed Sep. 15, 2017 by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally x-ray and fluoroscopic image capture and, in particular, to a versatile, multimode imaging system incorporating a hand-held x-ray emitter operative to capture digital or thermal images of a target; a stage operative to capture static x-ray and dynamic fluoroscopic images of the target; a system for the tracking and positioning of the x-ray emission; a device to automatically limit the field of the x-ray emission; and methods of use. 
     BACKGROUND OF THE INVENTION 
     Current fluoroscopic machines for orthopedic surgery tether a radiation source to an image intensifier by way of a large, fixed ‘c-arm.’ Manipulation of these larger, less portable machines is difficult and time consuming. It is frequently necessary to reposition the subject to fit the attainable field of view, which can be problematic during sensitive stages of a procedure. Thus, while c-arms are ergonomically suitable for surgical treatment of the spine and larger joints, existing units are heavy and cumbersome with respect to hand/wrist/arm and foot/ankle/leg extremity surgery, where relevant anatomy is smaller and more moveable by the surgeon. Existing fluoroscopic machines are also expensive, and emit large doses of radiation. In many cases, these larger radiation doses are not required for more delicate procedures, on extremities, for example, unnecessarily exposing the patient and surgeon to these higher doses. 
     In today&#39;s surgical environment, digital pictures and video are often needed to document relevant surgical anatomy or pathology. Thermal imaging can also be a useful tool, particularly for the extremity surgeon. Thermal imaging may be used to help determine if blood supply to an extremity or digit is threatened, and if a revascularization procedure is required. The addition of thermal imaging provides a quick and simple tool to guide intra-operative decisions. However, because existing fluoroscopic machines only capture x-ray images, the need to switch between digital and/or thermal image capture devices may create a delay in the completion of the surgery. Further, in a number of situations, the digital or thermal camera is not a sterile device, forcing the surgeon to either violate the surgical field, take a picture and then scrub back in, or have an assistant take the picture, which can create confusion about image correlation. 
     There is an outstanding need, therefore, for a small, lightweight system and method that allows the surgeon to capture x-rays without repositioning equipment. 
     SUMMARY OF THE INVENTION 
     The invention relates to an improved versatile, multimode radiographic systems and methods, allowing the surgeon to operate on a patient without interference, and capture static and dynamic x-rays and other still and video imagery without repositioning equipment, the subject or the surgeon. 
     Both x-ray emitters and detectors are described. One variation of a novel emitter allows for portable control of the emitter. Such an emitter can be lightweight and extremely maneuverable. Variations include that the portable emitter that is a handheld unit. Alternatively, the portable emitter can be affixed to a mounting structure that is either automated/controllable or simply bears the weight of the emitter to prevent the user from constantly holding the emitter. In additional variations, the emitter can be designed so that it is releasably coupleable with a mounting structure, which allows improved portability when needed and coupling to a mounting structure when desired. The emitter may include both an x-ray emitter along with at least one additional imaging modality such as a digital camera for producing a visual image, a thermal image, and an infrared image of a patient for the purposes of aiding diagnostic, surgical, and non-surgical interventions. Clearly, the systems and methods described herein can be used for non-medical applications where non-invasive imaging is desirable. 
     Ergonomic controls make acquisition of images easier and faster and a built-in display facilitates easy-to-use control functions. The device senses its distance from the subject and will block the activation and discharge of radiation if the x-ray tube is not at a safe distance; i.e., too close to the patient. The minimum distance can be defined in software and is adjustable based on intended use and other factors. The system automatically and intelligently manages its power state through the implementation and use of an inertial measurement unit (IMU) and various timing components. 
     The x-ray emitter may be used with available x-ray detector. One option is to mount the emitter in a fixture including a properly aligned detector plate, much like a traditional c-arm, though much smaller and more capable. An alternate variation is described herein and includes use of an emitter with a distinct x-ray capture stage, disclosed in detail, which automatically pivots, orients and aligns itself with the emitter to maximize exposure, quality and safety. 
     The inventive x-ray stage comprises a statically fixed platform, positioned during the outset of surgery, with an open cavity containing an x-ray sensor, an x-ray sensor positioning system, an emitter tracking system, a shielding system and a control unit. Optionally, the system can utilize an external display monitor or any other method for reviewing the captured image. 
     A variation of the improved systems described can include a non-invasive imaging system for examining an object for medical and non-medical inspections. Such a non-invasive imaging system can include an emitting apparatus configured to emit energy; an imaging sensor configured to generate an imaging signal upon the receipt of the energy when the emitting apparatus and imaging sensor are in an operationally aligned position; a platform having an external surface for positioning of the object and comprising at least one positioning mechanism located adjacent to the external surface; at least one positioning mechanism coupled to the imaging sensor allowing for movement of the imaging sensor adjacent to the external surface; at least one position tracking element affixed relative to the platform; where the emitting apparatus is moveable relative to the external surface of the platform; and a control system configured to determine a first coordinate measurement between the at least one position tracking element and the imaging sensor, the control system configured to determine a second coordinate measurement between the emitting apparatus and the at least one position tracking element, where the control system uses the first coordinate measurement and the second coordinate measurement to control actuation of the positioning mechanism moving the imaging sensor into the aligned position during or after movement of the emitting apparatus. 
     A variation of the improvements described herein also includes an improved method for non-invasively imaging an object. For example, such a method can include moving an emitting apparatus to a location relative to the object; determining a position of the emitting apparatus relative to at least one position tracking element; relaying the position of the emitting apparatus to a motor system that adjusts an imaging sensor into an operative alignment with the emitting apparatus; emitting energy from the emitting apparatus when the imaging sensor is in operative alignment with the emitting apparatus; and transmitting an image signal from the imaging sensor to a display. 
     Another variation of the method can include non-invasively imaging an object, by moving an emitting apparatus to a location relative to the object; emitting energy from the emitting apparatus to the object such that the energy is received by an imaging sensor configured to generate an image data; determining a position and orientation of the emitting apparatus relative to at least one position tracking element located in a fixed position relative to the image sensor; adjusting an image data based using the position and orientation of the emitting apparatus; and transmitting the image data to a display. 
     Variations of the system can include platforms that have a planar surface allowing for positioning of the object. Alternatively, a platform can include a support frame that allows securing of the object over a free-space such that the portion of the object located in the free-space can be viewed or inspected either entirely or substantially around the perimeter of the object. 
     In the systems, devices and methods described herein, which position the emitter and sensor in alignment or operative alignment, the degree of alignment can include any industry specifications that dictate alignment. For example, for medical applications, alignment of the systems and methods described herein can include a degree of alignment required to comply with the U.S. Code of Federal Regulations applying to the FOOD AND DRUG ADMINISTRATION DEPARTMENT OF HEALTH AND HUMAN SERVICES (e.g., 21 C.F.R. part 1020 incorporated by reference herein.) E.g., under 21 C.F.R. Neither a length nor a width of the x-ray field in the plane of the image receptor (sensor) shall exceed that of the visible area of the image receptor (sensor) by more than 3 percent of the source-to-image receptor distance (SID) and the sum of the excess length and the excess width shall be no greater than 4 percent of the SID and any error in alignment shall be determined along the length and width dimensions of the x-ray field which pass through the center of the visible area of the image receptor. In other applications, or alternate jurisdictions, the alignment discussed herein can vary to meet the respective requirements. Alternatively, variations of the systems, devices, and methods can include such metrics as obtaining a near orthogonal positioning between an emitter and receptor. 
     As with alignment, a minimum or maximum distance between an emitter and receptor can be established by industry standards. In one example, using the above FDA regulations, a maximum source-image receptor distance of less than 45 cm and means shall be provided to limit the source-skin distance to not less than 19 cm. 
     In use, the stage precisely tracks the position and angle of the x-ray emission, positioning and tilting the embedded sensor exactly to capture a precise, high quality x-ray image. The stage uses less power, corrects for any skew or perspective in the emission, allows the subject to remain in place, and allows the surgeon&#39;s workflow to continue uninterrupted. 
     In a “clinical” embodiment, an x-ray capture stage is statically positioned, with the emitter using the positioning to ensure the emission is only fired when the emission can be positively captured by the active area of the capture stage. Firing is also immediately terminated if acquisition of this positive capture is lost. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1 A  depicts an example of an operating room layout for use of the x-ray imaging system in a standard surgery of an extremity case. 
         FIGS.  1 B and  1 C  depict an alternate example of an operating room layout for use of the imaging system with a specialized operating table that improves access to an area of a patient. 
         FIG.  2    is a simplified, schematic representation of an x-ray emitter according to the invention. 
         FIG.  3    illustrates one embodiment of a control panel for use with an emitter. 
         FIG.  4    shows a safety lockout procedure for an x-ray emitter. 
         FIG.  5    depicts a representative sequence for emitter power management. 
         FIG.  6    illustrates a process by which a device captures concurrent images at the request of a user. 
         FIG.  7    is a drawing that illustrates the overall components of a preferred embodiment of a capture stage. 
         FIG.  8 A  is an oblique view of a sensor positioning system. 
         FIG.  8 B  illustrates infrared (IR) positioning tiles. 
         FIG.  9    is diagram that shows x, y movement of a sensor tray viewed from above. 
         FIG.  10 A  is an oblique diagram showing a band-operated image capture stage. 
         FIG.  10 B  is a schematic diagram of a band-operated stage with an identification of important components. 
         FIG.  11 A  is a side view showing a sensor tilt operation. 
         FIG.  11 B  is a side view showing a sensor panning operation. 
         FIG.  12 A  illustrates an arrangement whereby emitter need not be provided on an image stage platform. 
         FIG.  12 B  illustrates additional arrangements of the imaging system where a sensor can be configured to capture lateral views by moving above a plane of the table. 
         FIG.  13    is a view of an infrared emission device emitting infrared from 5 points allowing for relative position calculation in 3-dimensional space. 
         FIG.  14    illustrates a safety lockout of the capture stage based upon the disposition of the emitter. 
         FIG.  15    illustrates the capture of a fluoroscopic image. 
         FIG.  16    is a view showing the x-ray emission device with an aperture creating the widest cone. 
         FIG.  17    a view showing the x-ray emission device with an aperture creating a narrow cone. 
         FIG.  18    shows a control unit operative to adjust the aperture and cone. 
         FIG.  19    is a labeled view illustrating relative distances. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG.  1 A  depicts an example of operating room layout for use of an imaging system in a standard surgery of an extremity case. In this example, the surgeon  102  is operating on the patient&#39;s left hand. The patient  104  is lying in the supine position with the left upper extremity prepped and draped on a hand table  105  in the abducted position. The surgeon sits adjacent to the patient&#39;s side while a surgical assistant  106  sits across the hand table adjacent to the patient&#39;s head. Surgical instruments and equipment are laid out on the back table  108  immediately behind the surgical assistant. 
     In one variation, the imaging system uses x-ray imaging. As such, a sterilized x-ray emitter  110  according to the invention is placed on the surgical hand table  105  for use. A monitor  112  is positioned on a stand immediately adjacent to the hand table whereby x-ray, fluoroscopic, thermal and digital images can be wirelessly transferred from the x-ray imaging system to the screen for surgeon view. The emitter  110  allows the surgeon to hold it with one hand while operating another instrument such as a drill in the other hand. A detector stage according to the invention may be placed on or in the table  105  to gather radiographic imagery for storage and/or viewing on an external monitor such as device  112 . As discussed herein, the emitter can be handheld or can be affixed to a mounting structure that is either automated/controllable or simply bears the weight of the emitter to prevent the user from constantly holding the emitter. 
       FIG.  1 B  illustrates an additional variation of a system including a sensor  706  and an emitter  710  for use with a specialized operating table  300 . As shown, the operating table  300  includes structures  302  that stabilize the patient while allowing increased access around the patient&#39;s organs since a portion of the organ is suspended in free space. In this variation, a shell  707  containing the sensor  706  (as discussed below) is coupled to a first boom or arm  716 . The arm/boom  716  allows for movement of the sensor  706 . In an alternate variation, the boom  716  can be automated such that the sensor  706  is coupled directly to a controllable boom  716 . Likewise, the emitter  710  is coupled to a second arm or boom  714  that can be affixed to a wall, ceiling or portable frame structure.  FIG.  1 C  illustrate positioning of the sensor  706  and boom  716  adjacent to a body part of the patient  104  such that the emitter  710  can be positioned as desired by the operator or medical practitioner. In variations of the system, the boom or arm can also house components of the device, such as a heat sink, power supply, etc. allowing for a more compact and easy to maneuver emitter. In addition, either boom can be designed with features to aid the physician in performing the procedure. For example, the boom can incorporate a locking system so that the physician can position either the sensor  706  and/or emitter  710  and then lock the associated boom into position. Additionally, or in combination, booms can incorporate memory positioning such that the boom can automatically retract away from the surgical space to a pre-determined location such that it automatically moves out of the way of the physician when performing a procedure. In addition, memory locations can include the “last location” of the emitter or sensor, such that the system can automatically reposition the components in their last position prior to being moved away from the surgical space. 
       FIG.  2    is a simplified, schematic representation of an x-ray emitter according to the invention. The general configuration of the device is to be hand held, lightweight and extremely portable. The device preferably has a rounded, contoured handle to ergonomically fit the surgeon&#39;s hand and better direct fluoroscopy, digital and thermal imagery to the extremity and surgical field. Note that the drawing of  FIG.  2    is not intended to depict any particular ornamental appearance. 
     The back of the emitter  110  has a control panel whereby at least three different modes of operation can be activated: fluoroscopic mode, digital picture mode, or infrared thermal imaging mode. Once activated, each mode is controlled in the front of the device by a trigger  202 . Pressing the trigger once activates the device to take a single image (i.e., single x-ray or digital picture). Different modes of operation may be activated in different. As one example, holding the trigger  12  down may activate live fluoroscopy, digital video, or infrared thermal imaging.  FIG.  2    also illustrates the emitter  110  as being coupled to a power supply  221 . The power supply can be a battery  221  located remote from or within the emitter  110 . Alternatively, or in combination, the power supply  221  can be coupled via wiring between the emitter  110  and power supply  221 . In an additional variation, the battery  221  can be positioned within the emitter  110  and used in addition to a remote power supply  221  such that the emitter  110  can be disconnected from the external power supply temporarily with the internal battery  221  being used to provide power. 
       FIG.  3    illustrates one embodiment of the control panel for use with the emitter. The control panel is located on the rear of the emission handle and controls the various inputs and outputs of the system. The control panel is easily accessible for the user and is ergonomically designed to ease the manipulation of the emitter. The control panel comprises a large, clear screen  204  (i.e., LCD or OLED), a control button  302  located on the left of the unit, a control button  304  located on the right of the unit, and a center, clickable toggle button  206  located in the center. 
     Display screen  204  displays images and a digital control panel to control fluoroscopic, digital camera and infrared settings. The control panel may include a touch screen. Toggle button  206  controls power input in fluoroscopic and infrared modes, and digital zoom in the picture mode. The preferred emitter configuration houses a dynamic x-ray collimating cone  210 , digital camera lens  212 , infrared camera  214  and distance sensor  216 . The digital and infrared cameras preferable use charge-coupled device (CCD) technology. The distance sensor may be infrared, acoustic or other operative technology known to those of skill in the art of proximity and distance measurement. The sensor  216  continuously senses its distance from the patient and will block the activation and discharge of radiation if the x-ray tube is too close, for example, if less than 19 centimeters directly from patient. In addition, the system can include any number of auditory, visual, or tactile indicators to allow a physician or user of the system to determine that the sensor is within an acceptable distance or ready to fire. In additional variations, the auditory, visual, and/or tactile indicators are positioned such that the operative state of the system is identifiable without the need for the user to remove his/her focus from the object being examined. In one example, a visible indicator (e.g., one or more LEDs) is positioned on the emitter, which provides clearly distinguishable feedback regarding the distance, alignment, or any other operational conditions of the system. 
     The handle  200  tapers to the bottom of the device, which may house high-voltage power supply  218 , external charging port  220  and battery docking station  222 . Upon activation of the trigger  202  in x-ray or fluoroscopic modes, high voltage from power supply  218  is fed to x-ray generation unit  230  via the high voltage connector assembly  228 . Power produced by power supply  218  is converted to a suitable input voltage that can be used by the x-ray generation unit  230 . This power ranges from 1 kV to 120 kV, but typically ranges between 30 kV to 90 kV in conjunction with clinical application. 
     The x-ray generation unit  230  is based upon existing high-voltage emitters, though custom designed for small size required of the instant application. A suitable thickness of electrical insulating material surrounds the high voltage power supply  218 , connector assembly  228  and the x-ray generation unit  230  to prevent radiation loss and preserve good beam quality. All three components  218 ,  228 ,  230  are placed immediately adjacent to each other to minimize high voltage leakage and possible interference with low voltage components in the system. In an alternative embodiment, components  218 ,  228 ,  230  may be disposed in an external control unit (not shown). 
     A suitable layered combination of silicone rubber and epoxy encapsulates the x-ray generation unit  230  (except where x-rays are emitted into collimator) in order to shield radiation losses and dissipate high temperatures generated by x-ray tube operation. Radiation is produced by the x-ray tube and transmitted via the collimating cone  210  at the head of the device. Fluoroscopic settings including peak kilovoltage (kV), amperage (mA), and digital brightness, which are controlled by the digital control panel on the back of the neck. 
     The digital camera lens  212  and infrared thermal camera  214  are immediately adjacent to the collimating cone  210 , and these components are also shielded by insulation. The digital camera  214  is controlled by the placing the device in digital mode using the control panel. Pictures are generated via the trigger  202  located on the device handle. 
     Similarly, the infrared thermal camera  214  is controlled by the placing the device in infrared mode using the control panel. Live, infrared thermal imaging is generated by holding the trigger down. Digital x-rays, traditional digital visible and thermal images may be transferred and displayed on the external screen  112  shown in  FIG.  1   . Depending upon the level of cooperation between the emitter and the detector described herein below, x-ray images may be transferred directly to the external monitor for viewing. A memory  233  may be used to store any type of gathered image, and such images may be encrypted upon capture in accordance with co-pending U.S. patent application Ser. No. 15/466,216, the entire content of which is incorporated herein by reference. An audio pickup  235  may be provided for procedure memorialization or other purposes, and the recordings may also be stored in memory  233 , optionally in encrypted form as well. 
     The device is powered by an external, plugin power supply with external charging port  220 . The digital display, control interfaces, and trigger are controlled via the control system microprocessor electronic control unit  232  powered by a low voltage power amplifier system  234 . The low voltage amplifying system  234  and the microprocessor control system  232  are also conveniently located away from the high voltage power supply to further minimize interference. 
     The following Table lists the various control modes associated with the emitter using the buttons and toggle switch on the control panel of  FIG.  3   : 
     
       
         
           
               
               
            
               
                   
               
               
                   
                 Mode 
               
            
           
           
               
               
               
               
            
               
                 Control 
                 X-Ray 
                 Digital 
                 Thermal 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Center 
                 (206) 
                 Switch to Digital 
                 Switch to 
                 Switch to X- 
               
               
                   
                   
                   
                 Thermal 
                 Ray 
               
               
                 Left Button 
                 (302) 
                 Increate Output 
                 Toggle Macro 
                 Decrease 
               
               
                   
                   
                 Power 
                   
                 Exposure 
               
               
                 Right Button 
                 (304) 
                 Decrease Output 
                 Zoom In 
                 Increase 
               
               
                   
                   
                 Power 
                   
                 Exposure 
               
               
                   
               
            
           
         
       
     
     For a variety of reasons, both practical and certification, it is important to maintain a minimum distance between the subject and the x-ray generator. This distance can change depending on a number of factors and can be configured in the emitter&#39;s software.  FIG.  4    shows a process by which the device manages a safety lockout procedure of the x-ray emitter. The process to determine the safety lockout is as follows: 
       402 . The user initiates the x-ray emission process by depressing the trigger while in x-ray mode. This could be for either a fluoroscopic or still x-ray image. 
       404 . A distance setting is retrieved from the emitter&#39;s distance setting database. 
       405 . The distance measurement unit is activated and captures the distance between the end of the emitter and the subject directly in front of the emitter. 
       406 . The distance setting and distance measurements are relayed to the emitter&#39;s ECU Computation unit. 
       408 . At  408 , the ECU Computation unit uses the distance measurement, distance setting and an internal generator offset to determine if the emitter should fire. 
       410 . The fire/warn decision at  410  is determined by the ECU and relayed to the hardware units. 
       412 . At  412 , if the ECU determines that the subject is too close to the emitter, the unit will activate a warning procedure, displaying a message on the LCD panel and activating any lockout warning lights. 
       414 . If at  414  the ECU determines that the subject is at a safe distance, the emitter will begin the x-ray generation and emission process, signaling all internal and external components. 
     Due to the fact that the device can move freely in 3-dimensional space, the projected cone from the x-ray emitter varies in size based on the distance to the target. As such, the invention allows managed control over the cone size based on the distance of the x-ray emission device from a sensor positioned on the stage. 
       FIG.  16    illustrates a simplified rendition of an applicable x-ray source, which includes an anode  1602  and cathode  1604 . The anode typically includes a tungsten or molybdenum target  1606 . High voltage across the anode and cathode causes x rays to be produced at the target, which forms a cone  1608  that exits through an aperture  1610  in casing  1612 . 
     One aspect of the invention includes a telescoping chamber positioned in the direction of the aperture and sensor. The distance from the x-ray source to the output aperture can be increased or decreased by rotating the exterior chamber along a threaded interior mount. Moving the aperture closer to the source creates a wider angle, while moving it farther from the source reduces the angle, as shown in  FIG.  17   . 
     Making reference to  FIG.  18   , a control unit  1802  in the hand-held emitter controls the telescoping aperture. Based upon the process below, the control unit  1802  rotates a threaded shaft  1804 , whereupon the threads engages with grooves  1806  in telescoping chamber  1602 , causing aperture  1610  to toward and away from the x-ray source. 
     Referring to  FIG.  19   , the control methodology is as follows. First, the distance between the device&#39;s x-ray origin and the x-ray sensor is calculated. If the distance is outside an acceptable range of x-ray emission then no x-rays will be emitted. However, if the distance between the x-ray origin and the sensor (d s ) are within the acceptable range, the aperture will be automatically moved into place. The distance between the x-ray origin and the aperture (d a ) is then calculated and the control unit rotates the aperture chamber to the correct distance. 
     If R s  represents the radius of the x-ray emission as it contacts the sensor, then the angle between the normalized vector of the sensor plate and the dispersion cone can be represented as θ=tan −1 (R s /d s ). The distance that the aperture will need to be located from the emission origin to emit the correct dispersion of x-rays can calculated as d a =R a /tan(θ) where R a  represents the radius of the aperture. The control unit then allows the x-ray emission device to emit an x-ray which projects a cone at an angle θ onto the sensor. 
     While the telescoping cone adjustment mechanism described with reference to  FIGS.  16 - 19    is preferred, those of skill in the art will appreciate that a more conventional adjustable aperture (i.e., with translatable x-ray absorbing or blocking blades) may instead be used. The same math used above is applicable to this embodiment; that is, if the distance is outside an acceptable range of x-ray emission then no x-rays will be emitted. Conversely, if the distance between the x-ray origin and the sensor (d s ) are within the acceptable range, the aperture will be automatically opened or closed to facilitate firing of the source. 
     Different markets have different safety requirements. Additionally, depending on the subject (elderly, pediatric, otherwise healthy) the lockout may be adjusted to ensure that there are no safety issues associated with the emission. The device also preferably includes the capability to intelligently conserve power by utilizing the inertial measurement unit (IMU), distance sensor unit, as well as the operator initiated command inputs. The various durations for the power stages of the unit are user configurable so that the device can match the user&#39;s specific style and cadence. 
     The systems and methods described herein can also use multiple sensors for error correction and/or to improve positioning. For example, if an emitter and detector/sensor are in a given position and the system loses tracking of one or more sensors on the platform ordinarily the loss in tracking might cause a reduction in the frames per second (FPS) of the output image. To address this situation, the emitter can include one or more inertial measurement units that can track movement of the emitter to adjust the intervening frame especially when needed. The IMU will then be used to adjust the intervening frames to increase the FPS of the output. In some variations, with IMU&#39;s of sufficient accuracy, the IMU can be used in place of or in addition to sensors on the platform. 
     A representative sequence for power management is shown in  FIG.  5   . 
       502 . The user initiates the power sequence on the device by pushing a physical button (i.e.,  208  in  FIG.  2   ) on the emitter. This engages the device&#39;s electronics and moves the device into ON mode. 
       504 . Picking up the device is detected by the IMU in the emitter and immediately raises the power level to STANDBY. This STANDBY state initializes all power systems and raises the charge of the power supply to a medium level. 
       505 . If the user sets the device down or is otherwise not interacted with, either through movement of the emitter or through the initiation in the control panel or control computer, the device will automatically power down to the OFF stage after a duration of t0. 
       506 . The user has picked up the unit and has engaged the unit, either through altering of settings on the control panel itself or by bringing the device within range of a subject as detected by the onboard distance sensor. This further elevates the power level of the device by fully charging the power system to a state where the device is ready to fire, bringing the device into READY mode. 
       507 . If, after a duration of t1 without actively engaging the unit, the emitter will power itself down to the STANDBY level. 
       510 . The user initiates an x-ray capture by depressing the trigger  202  on the emitter. Assuming that all other safety checks are cleared, this further engages the power supply and emits the stream of x-ray photons at the subject until a state of  511 , at which time the emission is complete. The user can continue to emit x-ray photons indefinitely at  510 ′,  511 ′, however, as the device returns to READY mode. 
       511 . After a duration of t2 during which time the emitter has not been fired, the device will automatically power itself down to the STANDBY level at  520 . 
     As shown with points  508 ,  522 ,  524 , the device will follow the above timings to transition the device from the ON stages and finally to the OFF stage as the various durations elapse without positive engagement to maintain or change the power state. By utilizing these steps, the device can conserve power while maintaining in a ready state without any interaction from the user. 
       FIG.  6    illustrates a process by which the device captures concurrent images at the request of the user. Using the settings on the emitter&#39;s control screen, or by specifying a concurrent capture in the control unit, the emitter will initiate a process to capture any combination of x-ray, traditional digital and/or thermal images. The process to capture the images is as follows: 
       602 . The user initiates the capture sequence on the device by pulling the trigger of the emitter. This begins the capture process and concurrent imaging process for whatever grouping of sensors is enabled. 
       604 . The emitter immediately engages the X-Ray standby mode, preparing to fire the x-ray generator. 
       604 ′. Concurrently, if enabled, the traditional camera component focuses on the desired subject. This preferably occurs as soon as the trigger is depressed. 
       604 ″. Concurrently, if enabled, the thermal camera is powered on and begins its start sequence. This also preferably occurs as soon as the trigger is depressed. 
       606 . The x-ray system begins its safety checks, as illustrated in  FIG.  4   . 
       608 . The digital imaging camera captures a traditional image of the subject. The image is preferably automatically transferred to the control unit for display on an external monitor. 
       610 . The thermal camera captures a thermal image of the subject. The image is preferably automatically transferred to the control unit for display on an external monitor. 
       620 . In the preferred embodiment, after both  608  and  610  have completed, and all safety checks from  606  have been verified, the x-ray unit will fire an emission, generating an x-ray image in the sensor. The image is preferably automatically transferred to the control unit for display on an external monitor. Thus, the x-ray system will charge, verify safety, and discharge the x-ray only after all other systems have executed to minimize operational interference. 
     X-Ray Detector Implementations 
     The emitter described herein must be used in conjunction with an x-ray detector to gather radiographic imagery. The emitter is not limited in terms of detector technology, and may be used with any available flat-panel detector, even film. However, given fully portable nature of the emitter, steps should be taken to ensure that the emitter is properly oriented with respect to the detector to gather clear imagery while avoiding spurious or unwanted x-ray emissions. One option is to mount the emitter in a fixture including a properly aligned detector plate, much like a traditional c-arm though much smaller and more capable. A preferred option, however, is to use the emitter with the x-ray capture stages described below, one of which includes an embedded sensor that automatically pivots, orients and aligns itself with the emitter to maximize exposure quality and safety. 
     The preferred x-ray capture stage includes a statically fixed platform, positioned during the outset of surgery, with an interior cavity containing an x-ray sensor, an x-ray sensor positioning system, an emitter tracking system, a shielding system and a control unit. The x-ray capture stage is adapted to receive an x-ray emission from a separate emitter device, including the portable, hand-held unit described herein. The x-ray capture stage preferably also incorporates wireless (or wired) communications capabilities enabling review of a captured x-ray or fluoroscopic image to reviewed on an external display monitor or any other arrangement for the captured image including external storage. 
     There are broadly two capture stage embodiments. In a clinical embodiment, the stage tracks the emission and simply locks out the x-ray firing if it is not in line. A tracking stage embodiment also permits or locks out emission in accordance with alignment, but also precisely tracks the position and angle of the x-ray emission, positioning and tilting the embedded sensor to capture a precise, high quality x-ray image. This arrangement uses less power, corrects for any skew or perspective in the emission and allows the subject to remain in place, thereby enabling the surgeon&#39;s workflow to continue uninterrupted and capture x-rays without repositioning equipment, the subject or the surgeon. 
       FIG.  7    is a simplified view of a preferred embodiment of the x-ray capture stage, which includes a platform  702  with a hollow cavity including the embedded sensor  706 . In one configuration, the stage might have legs  703  and be used as a table. In another configuration, the stage might be wrapped in a bag and positioned underneath a patient. Thus, the platform  702  can be wrapped in a sterile drape and surgical procedures can be performed upon a platform such as table  105  in  FIG.  1   . 
     The capture stage cooperates with a separate x-ray emission device  710 . There are a number of different configurations and implementations of the x-ray emission device besides the hand held unit described in detail above, including wall-mounted, armature-mounted, and floor-mounted. Any implementation is compatible with the operative x-ray stage as long as the electronic systems of the emitter can communicate with the interface of the operative x-ray stage central control unit to provide for pivoting, orientation or alignment. 
     The platform  702  is in electrical communication with a central control unit  704 . A display monitor  712 , electronically connected to the control unit  704 , which may be used to both display images and provide overall system control. Generally, a user will interact with the emitter  710 ; however, in some cases, a user may interact with the central control unit  704  directly to manipulate images, setup specific capture scenarios, control parameters or adjust other settings. The system may also use a tablet, mobile phone or any other display device electronically connected to the central control unit for display purposes. The central control unit  704  and display may be combined in a single device, such as a laptop computer or other mobile computing device. Optionally, the central control unit can be electronically connected to multiple display units for educational or other purposes. 
       FIG.  8 A  is an oblique view of an x-ray capture stage according to the invention. In one specific arrangement the stage comprises is a hollow, sealed, shell that is roughly 20″×30″, although the overall size of the invention can be changed to conform to other surgical applications. The shell creates a cavity  800  housing an x-ray detection sensor  706  operative to capture an x-ray emission from an x-ray emitter. Suitable x-ray sensors are available from a variety of commercial manufacturers. The sensor  706  is attached to a motorized movement system used to pan and tilt the sensor within the cavity. This motorized system ensures that the sensor is precisely positioned for maximum image quality and capture view. 
     The x-ray sensor  706  is preferably mounted to a movable tray  802  that travels under controlled movement within the cavity  800 . The tray and sensor can move in the x-y direction and tilt along both axes as described below.  FIG.  9    is a diagram of a capture stage seen from above. The sensor  706  in tray  802  is mounted to translate on a series of motorized rails  720 ,  722 , allowing the sensor to position itself anywhere along the x and y axis within the shell. At least one of the x and y tracks may be a threaded rod, for example, each being driven by a motor for precise lateral movement of the tray  802  in the x and y dimensions. As a further alternative the x-y movement of the tray may be controlled with bands  1002 ,  1004  in  FIG.  10 A . Such bands are precisely controlled by rods  1006 ,  1008 , causing tray supports  1110 ,  1112  to translate tray  808 . Note that while four tray supports  902 ,  904  are depicted in  FIG.  9   , single supports  1110 ,  1112  may alternatively be used as shown in  FIG.  10 A . 
       FIG.  10 B  is a schematic diagram of a band-operated stage with an identification of important components. The X-ray detector is shown at  1030 , and the detector carrier is depicted at  1032 . This particular embodiment is driven by an H-shaped belt  1040 . Items  1042  and  1044  are small and large offset bearings, respectively. The belt is driven by motors  1050 ,  1052 . The stage housing is shown at  1060 , and power is brought in via cable  1062 . The detector tilt motors are indicated at  1070 ,  1072 . IR positioning tiles and IR emitters described with reference to  FIG.  8 B , are shown at  850  and  852 , respectively. The typical IR emitters described herein are active beacons since they actively emit a signal or energy that is received by the emitter to aid in determining a position of the emitter. Alternatively, or in combination, additional variations of the methods, systems and devices described herein can include passive markings or objects to aid in determining orientation of the emitter. The systems, devices and method can include camera or emitter that simply record a specific pattern (e.g., a QR symbol or some unique object in the surgical area such as a clock, table, fixture, etc.). The system will then rely on a computer to use these patterns in place of, or in combination with, IR beacons to determine a position of the emitter. In this latter case, the emitter position is calculated by the computer or other processing unit. 
     In all stage embodiments, the upper cover of the platform or shell is covered with a radiolucent material (i.e.,  1018  in  FIG.  10 A ). However, the lower base of the platform (i.e.,  1020  in  FIG.  10 A ) is preferably coated with an x-ray absorbing material such as lead. This coating prevents the excess x-rays from penetrating through the field and being absorbed by the operator of the emitter. This x-ray absorbing undercoating also prevents excess x-ray emission from bouncing off the floor and scattering throughout the facility. The sides of the platform may be constructed from a radio-opaque material as well. 
       FIGS.  11 A,  11 B  are diagrams that show a pan and tilt mechanism. In  FIG.  11 A , the sensor tray  802  is positioned within the cavity and the sensor  706  is tilted around the y-axis. In  FIG.  11 B , the sensor tray  802  is tilted along both the x-axis and the y-axes. This panning and tilting allows the sensor to be precisely positioned to capture an x-ray image while minimizing the distortion created by the offset angle of the emission device. That is, the capture stage and x-ray emitter are coordinated to minimize skew and maximize capture of both x-ray and fluoroscopic images. By moving the sensor within the stage, the user does not need to reposition the subject to get a clear, usable x-ray or fluoroscopic image. 
     In the case of a handheld emitter, wherein the emission device is physically decoupled from the stage, it is important to position the sensor relative to the emitter for quality and safety reasons. Different techniques may be used to accomplish this goal. As shown in  FIGS.  8  and  10   , a plurality of position tracking implements  830  may be mounted to the ends or corners of the tray. While these implements may be used in all four corners, only one is necessary for accurate triangulation. These implements may be based upon ultrasonic tone generation or infrared emission. In these embodiments, acoustic or infrared signals generated in the platform are detected by the emitter device, causing the sensor to translate and tilt to maximize capture. A further embodiment may utilize magnetic position and orientation sensors and detectors of the type used in surgical navigation to orient the tray and x-ray sensor. 
     The emitters  830  are used to measure the distance from a point  810  on the hand-held unit  710  to three (or more) fixed points  830  attached the stage. These distances are depicted as D 1 , D 2  and D 3  in  FIG.  8 A . Based upon these distances, the system employs a tracking method to precisely locate a center point  801  on the sensor  706  and angle (θ 5 ) of the emission from the source to the platform. An exemplary implementation of this tracking system would include a combination of infrared sensors within the platform and the hand-held unit, as well as a gyroscope in the stage and hand-held unit to detect the angle θ 5 . 
     The positioning of the detector uses a number of sensors in concert. When the user picks up the hand-held unit, the system enters a ready state. The infrared beacons on the corners of the table illuminate. The positioning tracking camera on the hand-held unit immediately starts analyzing the infrared spectrum captured within a 140-degree field of view. The camera is searching for patterns of infrared light. Each corner  830  has a specific pattern that determines which corner of the stage the infrared camera in the hand-held unit is looking at. 
     Making reference to  FIG.  8 B , an IR positioning emitter tile  850  sits at each corner of the operative or clinical stage. The diagram is an example of four unique tiles. When using the mounted positioning beacons, the pattern will be different. These tiles contain a number of infrared emitters  852 , usually five individual emitters, arranged in a specific pattern. Each tile contains a different pattern of the five IR emitters. As the operator moves the x-ray emitter around the stage, the IR positioning camera captures and analyses the IR emissions from the tiles. Because each tile has a unique pattern, the camera is able to determine its exact position in relation to the table. Additionally, because each tile has a unique pattern of multiple lights, the system can determine the exact position from the tile in XYZ space. 
     Optionally, or in addition to this unique IR layout, the IR emitters can flash in a syncopated manner. By modulating the frequency of the flashes, it is possible to add an additional uniqueness signature to each tile, allowing patterns to repeat in a scenario with a large number of tiles. Because of this unique arrangement, only a single corner of the unit, or single positioning beacon, needs to be visible to the emitter to allow the system to fully function. That is, due to the layout of the pattern, the camera can triangulate its position in space relative to each corner. By using the triangulation data, as well as the orientation data from the IMU unit on the emitter, the system can determine the center point of the emission. The stage will then move the center point to that area of the stage and tilt the detector to be as perpendicular to the emission as possible. While the sensor is moving itself into position, the collimator on the emitter adjusts the output of the beam to insure ensure that it is illuminating the detector panel only. 
     The position information from the combination of the sensors  830  is routed through the control unit (i.e.,  704  in  FIG.  7   ), which interpolates the raw sensor data into an aim point on the platform. The platform then moves the sensor tray  802  to the specified point. The platform then tilts the sensor into the correct orientation ( 05 ) to remove as much skew as possible. Stated differently, assuming the x-ray source in emitter  710  emits radiation with respect to an axis  803 , the goal is to place the axis  803  as close as possible to the center point  801  of the sensor, with the plane of the sensor being as perpendicular as possible to the axis  201  to minimize skew. 
     The x, y, pan and tilt positioning of the tray and sensor may be accomplished without position emitters in the platform portion of the system.  FIGS.  12 A and  13    illustrate an alternative system and method of position calculation that removes the dependency of having position emitters embedded in the table. Instead, the position of the x-ray emitter in relation to the capture stage and x-ray detection sensor can be calculated based on external position emitters. As noted above, the emitter can be purely hand-held to allow a practitioner to move the emitter in free-space. Alternatively, the emitter can be moveable with (or coupleable to) a support structure that maintains the emitter in position relative to the object without requiring the physician to continuously hold the emitter. 
     The process to determine the location of the x-ray emission device in accordance with this embodiment is as follows: 
     The external positional emission device(s) are installed onto a fixed location and contain a series of infrared emitters. This emission device releases infrared patterns from 5 sides of a cubic object  1202  resulting in infrared energy being sent out from slightly different origins. 
     The stage detects the infrared pattern and calculates the relative position from the stage to the center of each infrared emitter in 3-dimensional space. This position will be considered [xsi, ysi, zsi]=[−xei, −yei, −zei] with s representing the stage, e representing the infrared emission device, and i representing the index of the infrared emission device (if leveraging multiple infrared emitters). 
     The x-ray emission device continually detects the infrared signal patterns and determines the relative location of the emission device to the center of each infrared emitter in space. This relative position is relayed to an emission position control unit for each emitter. This position may be considered [xhi, yhi, zhi]=[−xei, −yei, −zei], with h representing the x-ray emission device, e representing the infrared emission device, and i representing the index of the infrared emission device. 
     The emission position control unit will receive the relative positions of the x-ray emission device ([xhi, yhi, zhi]). Using these relative positions, the emission position control unit calculates the position of the x-ray emission device relative to the stage ( FIG.  13   ), resulting in [xhi−xsi, yhi−ysi, zhi−zsi]. This operation is performed for each infrared emission device (i), which can then be used to deduce the margin of error. 
     After the stage applies the position along with the other pieces of data as mentioned in the original filing, the stage moves and rotates the x-ray sensor plate into the correct position to capture the x-ray image. 
       FIG.  12 B  illustrates a variation where an emitter  710  can apply energy to a sensor/detector  706  that is configured to move as discussed herein but can also move to enable a lateral image. In the illustrated variation, the sensor/detector  706  moves outside of the center X axis of the table  105  to capture lateral views of the patient  104 . However, variations of the sensor  706  can include configurations where the table is non-planar and is configured to receive the sensor  706  above a plan in which the patient is positioned.  FIG.  12 B  also illustrates an additional concept where multiple detectors  706  are used as described herein. In such a variation, the sensors  706  would be moved as described herein, but the sensor having the best operational alignment would be used to generate a signal. 
     Safety Lockout Procedures 
     Just as it is important to limit emissions from the emitter to specific target distances, for a variety of reasons, both practical and certification, it is important to only fire the x-ray generator when the emitter is properly aimed at the capture stage. By preventing the x-ray generator from emitting photons while not pointed at the stage, the safety of the system is improved and the performance of an emitter is increased.  FIG.  14    illustrates the process by which the device manages the safety lockout of the emitter and captures an x-ray image, with the numbers corresponding to the numbers in  FIG.  14   : 
     1. User initiates the capture process by signaling through the emission device  110 , typically by depressing a trigger. The emitter sends a data packet (D) to the controller containing the request for capture, the distance measurements (d1, d2, . . . ) and the angle of the emitter. 
     2a. The Controller validates that the emitter is in a safe orientation. 
     2b. If the Controller discovers that the emitter is not in a safe, valid orientation, the controller sends an error message to the emitter. This prevents the emitter from firing and signals to the user that there is a problem. 
     3. The stage positions the sensor in accordance with the position of the emitter. The stage will tilt the sensor so that it is in the correct orientation to capture a clear image. The orientation will be as close to the complementary angle of the emission as possible. 
     4. The stage then sends a confirmation message to the controller after the position has been established. 
     5. The controller forwards the start message to the emitter. The emitter will then execute any additional safety or preparation tasks. If the emitter believes the environment is safe to fire, the emitter will then fire the x-ray. 
     6a. The emitter fires a pulse of x-ray photons at the stage for the requested amount of time. 
     6b. During the emission of the x-ray photon stream, the emitter constantly streams any updates to the position and angle to the central controller. 
     6c. The controller records these positional updates and relays them to the stage. 
     6d. The stage will rapidly and constantly update the position and angle of the sensor to optically stabilize the x-ray image. 
     7. The sensor captures the emission of x-ray photons from the emitter and builds an image. 
     8. Upon completion of the x-ray emission, the sensor relays the data to the control unit. 
     9. The control unit then cleans up the image from the sensor using a variety of know optical enhancement techniques. If applicable, the control unit will leverage the stored movement data from the emitter to further enhance the output. 
     The above process allows the emitter to ensure that the emission will be directed at the sensor and the stage as opposed to any other arbitrary target. By moving the sensor into place below the emission target, the user can create a resolute, flexible image of the exact desired portion of the subject without having to reposition the subject. 
       FIG.  15    illustrates the process by which the device captures a fluoroscopic image. The process for capturing a fluoroscopic image is very similar to capturing a static x-ray image; however, the fluoroscopic process will repeat several emissions and image captures to create a moving image. The process to ensure the safe emission as well as capture the fluoroscopic image, with the numbers corresponding to the numbers in  FIG.  15   : 
     1. User initiates the capture process by signaling through the emission handle, usually by depressing a trigger. The emitter sends a data packet (D) to the controller containing the request for capture, the distance measurements (d1, d2, . . . ) and the angle of the emitter. 
     2a. The Controller validates that the emitter is in a safe orientation. 
     2b. If the Controller discovers that the emitter is not in a safe, valid orientation, the controller sends an error message to the emitter. This prevents the emitter from firing and signals the user that there is a problem. 
     3. The stage positions the sensor in accordance with the position of the emitter. The stage will tilt the sensor so that it is in the correct orientation to capture a clear image. The orientation will be as close to the complementary angle of the emission as possible. 
     4. The stage then sends a confirmation message to the controller after the positioning. 
     5. The controller forwards the start message to the emitter. The emitter will then execute any additional safety or preparation tasks. 
     In the fluoroscopic mode, the emitter will repeat the following steps while the emitter device continues to request additional fluoroscopic frames, as follows: 
     6a. The emitter fires a pulse of x-ray photons at the stage for the requested amount of time. 
     6b. During the emission of the x-ray photon stream, the emitter constantly streams any updates to the position and angle to the central controller. If at any time during the fluoroscopic process, the operative stage detects the emission is not aimed at the stage, the stage will send a termination signal to the emission device and skip directly to step  9 . 
     6c. The controller records these positional updates and relays them to the stage. 
     6d. The stage rapidly and continuously updates the position and angle of the sensor to optically stabilize the x-ray image. 
     7. The sensor captures the emission of x-ray photons from the emitter and builds an image. 
     8. The sensor immediately transfers the image to the control unit. At this time, a brief cleanup process is executed and the image is displayed on the external viewing device. This fluoroscopic frame is saved to memory. 
     The constant repetition of this process creates a moving image on the external display. The process will repeat until the user releases the trigger of the emission device. 
     9. Once the user releases the trigger of the emission device, the control unit “cleans up” the stored frames from the sensor using a variety of known enhancement techniques. If applicable, the control unit will also apply any stored movement data from the emitter to further enhance the output. The control unit will then combine the fluoroscopic frames into a single video for repeated playback. 
     The above process allows the user to see a live fluoroscopic view of the subject in real time. By storing the images and reprocessing after the capture is complete, the device can create a high quality, single fluoroscopic video for display and review at a later time. 
     While the above descriptions provide exemplary details of the invention in order to provide an understanding of the invention, routine engineering adjustments may be employed to practice the invention without departing from the spirit or scope of the invention. Further, while the invention is described for use in x-ray imaging for surgical purposes, it could be used in other medical applications such as general medical imaging, veterinary and bone densitometry. The system and method may also be used for non-medical applications such as industrial imaging, metal fatigue inspections, weld-inspection, for security inspections, and the like.